Journal Of The American Association For Laboratory Animal Science[JOURNAL]
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200 papers
Armenian Hamsters (Nothocricetulus migratorius): A New Host Susceptible to Corynebacterium bovis Infection and Disease.
Cheleuitte-Nieves C, Miranda IC, Michelson A … +8 more , Walton K, Geist GE, Nickerson K, Wipf JR, Carrasco SE, Monette S, Mammone R, Lipman NS
J Am Assoc Lab Anim Sci · 2025 Jul · PMID 40695468 · Full text
Corynebacterium bovis causes skin disease in immunocompromised mice and possibly rats. In 2022, scaly skin and mortality were observed in 7- to 11-d-old neonates (n = 8) from a primiparous Armenian (Nothocricetulus migra...
Corynebacterium bovis causes skin disease in immunocompromised mice and possibly rats. In 2022, scaly skin and mortality were observed in 7- to 11-d-old neonates (n = 8) from a primiparous Armenian (Nothocricetulus migratorius) hamster breeding pair in a newly established colony. C. bovis was detected by culture and PCR, and affected animals had moderate to severe acanthotic, hyperkeratotic lesions with intralesional C. bovis confirmed by in situ hybridization. Intrafollicular Demodex cricetuli mites, an ectoparasite found in all laboratory-maintained Armenian hamsters, were also identified in affected animals. To elucidate the role of D. cricetuli on C. bovis-associated disease and maintain adult hamsters without the need for sustained mite treatment, a D. cricetuli-free colony was generated by treating breeding pairs and their 1- to 3-d-old neonates with topical fluralaner (35 mg/kg), and a prospective study was undertaken to compare C. bovis-associated pup mortality in D. cricetuli-free and D. cricetuli-infested hamsters. During the ensuing 22 mo, 4 of 96 (4.2%) litters born exhibited C. bovis-associated disease and/or mortality. The litters were born to 4 different nulliparous breeding pairs (n = 47, 9%). Of the 4 affected litters, 2 were D. cricetuli-infested while 2 were D. cricetuli-free. C. bovis was routinely cultured with a variable bacterial burden that had no association with mortality or skin lesion severity from all hamsters, independent of their D. cricetuli status. The severity of histologic pathology appeared to correlate with clinical presentation and mortality in neonates. Whole genome sequencing was performed on 4 hamster C. bovis isolates, which revealed a close genetic association among the isolates as well as with previously characterized mouse and rat C. bovis isolates.
Alfaxalone as a Total Intravenous Anesthesia Protocol in New Zealand White Rabbits (Oryctolagus cuniculus) Improves Cardiovascular Stability Compared to Isoflurane.
Tsai JY, Palomera EE, Kundo JP … +3 more , Jampachaisri K, Pacharinsak C, Reyes NL
J Am Assoc Lab Anim Sci · 2025 Jul · PMID 40695466 · Full text
Alfaxalone has been studied for anesthetic induction of rabbits with rapid onset and a short duration of action; however, it has been minimally evaluated as an option for anesthetic maintenance. This study compared alfax...
Alfaxalone has been studied for anesthetic induction of rabbits with rapid onset and a short duration of action; however, it has been minimally evaluated as an option for anesthetic maintenance. This study compared alfaxalone-based total intravenous anesthesia maintenance protocols against inhaled isoflurane, the current standard for anesthetic maintenance in rabbits. Twenty-four male New Zealand White rabbits were assigned to 1 of 3 treatment groups: isoflurane alone, alfaxalone with buprenorphine, or alfaxalone with midazolam. All rabbits were premedicated with buprenorphine HCl (0.02 mg/kg SC) and induced with alfaxalone (6 mg/kg IM). Following intubation and with supplementation of 100% O2, rabbits were maintained for 1 h on either isoflurane (2.5%) or alfaxalone continuous rate infusion (CRI) (0.2 mg/kg/min). For rabbits on the alfaxalone CRI, boluses of buprenorphine HCl (0.01 mg/kg IV or SC) or midazolam (0.1 to 0.3 mg/kg SC) were given upon induction or adjunctively as needed dependent on positive tail-pinch responses that were conducted at timepoints t0, t15, t30, t45, and t60. Heart rate, invasive blood pressure, respiratory rate, end-tidal CO2, percent O2 saturation, and temperature were recorded every 5 min. Surgical plane of anesthesia was characterized by lack of positive response to a tail clamp and was reached in all anesthetic groups. Results showed significant reduction in heart rate of the alfaxalone groups while there was no significant difference in mean arterial pressure compared with the isoflurane groups. However, respiratory rate in the alfaxalone groups was decreased with associated increases in end-tidal CO2 levels. There were no significant differences noted between alfaxalone treatment groups. The results confirmed that CRI alfaxalone (total intravenous anesthesia) should be considered as a potential anesthetic alternative to isoflurane anesthesia in rabbits, although special attention to respiratory monitoring and management is warranted.
Improved Detection of Murine Pathogens Using Sentinel-Free Media Compared to Live Animal Sampling.
Woolsey JM, Bonica J, Godbey S … +1 more , Washington IM
J Am Assoc Lab Anim Sci · 2025 Jul · PMID 40695465 · Full text
Health monitoring of rodent colonies has traditionally used live animal (LA) sampling by means such as the use of soiled bedding sentinels (SBS), with the associated expenditure of labor, supplies, and animals. In the sp...
Health monitoring of rodent colonies has traditionally used live animal (LA) sampling by means such as the use of soiled bedding sentinels (SBS), with the associated expenditure of labor, supplies, and animals. In the spirit of the 3Rs, sentinel-free (SF) approaches are becoming more common. PCR testing of environmental samples is replacing traditional SBS-based testing for routine health monitoring of rodent colonies. Passive sampling of in-cage media exposed to pooled, soiled bedding is effective for detecting some common rodent pathogens. We hypothesized that PCR testing of commercially available media exposed to soiled bedding would be as effective as sampling SBS, or SBS combined with samples from colony animals, for detecting several enzootic organisms of mice (Mus musculus) within our facility. Media were placed in IVC cages and exposed to pooled dirty bedding from all cages on a rack side at biweekly cage changes during a 3-mo period. PCR results of the SF soiled bedding-exposed media were compared with results from feces, pelt, and oral swabs from SBS with and without SBS combined with 10 randomly sampled colony animals from the same rack side over the same period. Detection rates were similar for murine norovirus and Staphylococcus xylosus using SF testing compared with SBS with and without direct colony samples. Five organisms, Proteus mirabilis, Rodentibacter heylii, Staphylococcus aureus, Klebsiella oxytoca, and Klebsiella pneumoniae, were detected by SF testing, but not by LA samples. Demodex musculi, Entamoeba, Proteus mirabilis, Helicobacter spp., and Rodentibacter heylii were detected at significantly higher rates by SF testing compared with SBS with and without colony animal samples. SF testing detected organisms of zoonotic concern (S. aureus, K. pneumoniae) that were undetected by LA testing. SF testing detected organisms at similar rates during 2 consecutive quarters. We conclude that PCR testing of media exposed to pooled soiled bedding effectively detects these common enzootic organisms.
From the Archives, in Recognition of the 75th Anniversary of AALAS: The History of Commercial Production of Laboratory Rodents (1980).
Otto G
J Am Assoc Lab Anim Sci · 2025 Jul · PMID 40695464 · Full text
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Detection and Remediation of Pneumocystis murina Infections by Environmental Health Monitoring.
Habenicht LM, Hamilton S, Hart ML … +4 more , Fink MK, Fong DL, Leszczynski JK, Manuel CA
J Am Assoc Lab Anim Sci · 2025 Jul · PMID 40695463 · Full text
The increased sensitivity of PCR testing for environmental health monitoring compared with soiled bedding sentinel (SBS) serology can identify rodent pathogens thought to be excluded from a research animal facility. Exha...
The increased sensitivity of PCR testing for environmental health monitoring compared with soiled bedding sentinel (SBS) serology can identify rodent pathogens thought to be excluded from a research animal facility. Exhaust dust testing for rodent pathogen surveillance revealed the presence of Pneumocystis murina in 3 colonies that was undetected in previous years of SBS serologic testing. This case series describes the process of follow-up testing used to identify and eliminate or isolate animals infected with P. murina. PCR testing of exhaust dust at the rack, row, and cage level on individually ventilated cage (IVC) racks was leveraged to identify all infected cages. Based on our experience, IVCs and standard cage handling practices are sufficient to contain this organism in mice with altered immune systems, which can harbor chronic P. murina infections. Institutions with an active mouse import program are at ongoing risk of accepting P. murina-positive animals from institutions still relying on SBS serology to identify this pathogen. PCR testing of rodent cage-generated dust can be used to pinpoint P. murina-infected mice housed on IVC racks.
Induction of Endometriosis in a Menstruating Mouse Model (Mus musculus): A Translational Animal Disease Model.
Howe CA, Coté JJ, Stoos CT … +3 more , Hallgren JJ, Bredehoeft MR, Gelineau-van Waes JB
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683665 · Full text
Improved animal models of endometriosis are needed to accurately represent the pathophysiology of human disease and identify new therapeutic targets that do not compromise fertility. There is tremendous heterogeneity amo...
Improved animal models of endometriosis are needed to accurately represent the pathophysiology of human disease and identify new therapeutic targets that do not compromise fertility. There is tremendous heterogeneity among published rodent models of endometriosis, and the etiology and pathogenesis of endometriosis remain undetermined. The vast majority of endometriosis is found in menstruating women; however, no published mouse models have induced endometriosis in a menstruating mouse, further limiting our understanding of the disease. Our goal was to develop a novel, translationally relevant mouse model of endometriosis in a menstruating mouse by transplanting donor menstrual endometrium into the peritoneal cavity of menstruating, immunocompetent, intact recipients. We initially compared 4 different experimental groups to optimize implanted menstrual tissue type and method of implantation into intact, normally cycling recipient mice. To further optimize this model, a novel fifth experimental group was compared in which discrete pieces of menstrual donor endometrium were implanted via laparoscopy into menstruating recipient mice. Lesions were confirmed to be endometriosis based on histopathology. The use of laparoscopy to place discrete fragments of menstrual phase endometrium intraabdominally was the most effective method for induction of endometriosis. This method was just as effective when used to induce endometriosis in menstruating recipient mice. Menstruating mice returned to normal estrus cyclicity after induction of disease, which can allow for assessment of therapeutic interventions on fertility. This is a novel translationally relevant mouse model of endometriosis in a menstruating mouse that can be used to explore and elucidate the etiology and pathogenesis of this disease.
Evaluation of Serum L-FABP as a Biomarker and Hepatoprotective Effect of L-FABP Using Wild-Type and Human L-FABP Chromosome Transgenic Mice.
Ohata K, Ryu K, Uno K … +5 more , Teoh SH, Sugaya T, Kamijo-Ikemori A, Suzuki-Kemuriyama N, Miyajima K
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683662 · Full text
Metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH) are the major prevalent liver diseases and growing public health problems worldwide. Because MA...
Metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH) are the major prevalent liver diseases and growing public health problems worldwide. Because MASLD/MASH is known as a risk for progression to cirrhosis and development of hepatocellular carcinoma, therapeutic approaches and biomarkers that reflect the presence and progression of the disease are needed. In recent years, the usefulness of serum L-FABP levels has been reported for monitoring of hepatocellular damage in various liver diseases including MASLD/MASH in humans. Furthermore, it is reported that hepatic L-FABP is a potential therapeutic target. The purpose of this study was to validate the usefulness of serum L-FABP as a liver damage biomarker in the mouse model of MASLD/MASH and to evaluate the function of L-FABP in the pathogenesis of MASLD/MASH. First, we evaluated the changes in serum L-FABP as a liver damage biomarker using a mouse model of MASLD/MASH fed a choline-deficient, methionine-lowered, amino acid-defined, high-fat diet. The results demonstrated that serum L-FABP levels in the MASLD/MASH model continuously increased with the progression of steatosis and correlated with histopathologic changes. Serum L-FABP may be a useful biomarker for liver disease with respect to translational research bridging between animal models and human clinical research. Further, we showed that in human L-FABP chromosomal transgenic mice L-FABP had a suppressive effect on the gene expression associated with oxidative stress, fibrosis, and inflammation in the MASLD/MASH model. L-FABP is not only a biomarker in the blood but also has the functional aspect of hepatoprotection against MASLD/MASH.
Influence of Multiple Factors on Rhesus Macaque (Macaca mulatta) Use of a Feeding Enrichment Device.
Cowan-Brown JM, Clay AW, Perlman J … +3 more , Lam C, Kramer A, Bloomsmith MA
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683661 · Full text
We studied the effect of different filler items on rhesus macaques' use of a feeding enrichment device called the 'browsing bowl.' We examined use of the device as affected by calories, sugar content, and volume of diffe...
We studied the effect of different filler items on rhesus macaques' use of a feeding enrichment device called the 'browsing bowl.' We examined use of the device as affected by calories, sugar content, and volume of different fillers as well as the presentation of each filler as 1) whole, loose, or smeared and 2) frozen or not frozen. In addition, we examined the impact of age and sex of the monkeys on use of the device. Fifty-eight macaques were observed across 30-min sessions with the device, with one session for each of 12 different fillers. Scans occurred every 2.5 min, at which point the monkeys were scored as interacting or not interacting with the device. Subjects were recorded as interacting with the device during 47.6% of all observed scans and during 80% of the first 2 scans per session. Frozen items were associated with a significantly higher mean engagement (ME; proportion of observed scans in which animals engaged with the device) than items that were not frozen items (t(57) = 12.91, P < 0.001). Whole presentations were associated with a significantly higher ME than for smeared (P < 0.001) or loose (P = 0.005) items. Loose items were associated with a significantly higher ME (P < 0.001) than for smeared items. Sugar and calorie content did not impact use of the device. Younger monkeys used the device more than for older monkeys, and female monkeys used the device more than did males. We conclude that some filler items encourage more foraging behavior than others, and that it is possible to generate relatively long (up to 30 min) foraging bouts by altering the presentation of foods rather than increasing calories or sugar content. Indeed, some fillers were still present and engaged with at the end of the observation session.
Using Comparative Transcriptomics and Histology to Identify Significant Differentially Expressed Genes Associated with Retained Placenta in Humans and Rhesus Macaques (Macaca mulatta).
Jasani S, Vaseeharan A, Singh A … +4 more , Washburn E, Stovall M, Atkins H, Covington D
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683660 · Full text
Retained placenta is an important reproductive complication that affects humans and nonhuman primates (NHPs). Accurate prediction of retained placenta in both species is a current challenge because the etiology is unknow...
Retained placenta is an important reproductive complication that affects humans and nonhuman primates (NHPs). Accurate prediction of retained placenta in both species is a current challenge because the etiology is unknown, biomarkers are inadequate, and data are heterogeneous. Through a comparative approach, this study identifies 34 significantly differentially expressed genes associated with retained placenta shared between humans and NHPs. Pathway enrichment revealed upregulation in innate and adaptive immunity in addition to pathways related to hemostasis. Retained placentas in NHPs had higher histologic evidence of inflammation as compared with human samples. These cross-species transcriptional results can serve as an initial step to guide NHP refinement as a model system and inform retained placenta biomarker discovery in both humans and NHPs.
Animal Research at a Crossroads: Strengths, Weaknesses, Opportunities, and Emerging Threats.
Thompson-Iritani SA, Newsome JT
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683658 · Full text
Research involving animals is pivotal to advancing biomedical and veterinary sciences, contributing to discoveries that have saved countless lives and improved global health. However, the field faces increasing scrutiny...
Research involving animals is pivotal to advancing biomedical and veterinary sciences, contributing to discoveries that have saved countless lives and improved global health. However, the field faces increasing scrutiny from ethical, scientific, and societal perspectives. This paper applies a strategic Strengths, Weaknesses, Opportunities, Threats (SWOT) analysis, adapted from traditional business planning, to critically evaluate the current landscape of animal research, offering a balanced perspective on its contributions and challenges. While typically used to assess organizational performance, here the framework is reinterpreted to provide a structured, holistic view of the internal and external factors shaping ethical, scientific, and societal aspects of animal research. Strengths include its foundational role in Nobel Prize-winning discoveries, medical advancements, and therapeutic safety. Key weaknesses, such as public mistrust, ethical concerns, resource limitations, and rigor and reproducibility, are examined. Opportunities lie in the advancement of study refinements, improved methodologies, and fostering stakeholder communication. Threats such as misunderstanding, regulatory complexities, and resource constraints are addressed through strategic recommendations, including investment in Replacement, Reduction, and Refinement (3Rs), effective public engagement, and global harmonization of standards. This paper concludes by presenting an actionable roadmap to ensure the continued ethical and impactful use of animals in research while embracing innovation and maintaining public trust.
Long-Term Storage of a Natural-Ingredient Diet within Variable Conditions of Temperature and Humidity.
Towns K, Horvath A, Darbyshire A
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683657 · Full text
Institutions with aging structures may face difficulties maintaining consistent temperature and humidity for feed storage due to continued daily use of older heating, ventilation, and air conditioning systems and mainten...
Institutions with aging structures may face difficulties maintaining consistent temperature and humidity for feed storage due to continued daily use of older heating, ventilation, and air conditioning systems and maintenance of structural integrity since the environmental efficiency of buildings often reduces as structures age. Consequently, institutions can face difficult financial decisions regarding whether repairs or new structures should be considered when compliance with standards is inconsistent. Replacing running or currently functioning heating, ventilation, and air conditioning systems that lack efficiency in comparison with newer systems is often not considered wise use of institutional resources. As this concern was faced and discussed during a recent campus AAALAC site visit to our institution, our IACUC requested additional information related to safe storage of feed in our current older buildings. Three test group environments of control/Guide for the Care and Use of Laboratory Animals (Guide)-recommended temperature/humidity, variable temperature/humidity, and high temperature/Guide-recommended humidity were used to store feed for a total of 6 mo. Full feed analysis, retinol levels, thiamine levels, and mold/yeast levels were evaluated at 0, 3, and 6 mo following storage. Study findings demonstrated that the nutritional content for feed remained relatively equivalent across the timespan as well as across the different storage conditions. More importantly, all storage conditions showed no increases in yeast/mold growth and acceptable levels of both thiamine and retinol at 6 mo. Our findings suggest that the diet tested was still usable for feeding animals after storage in the tested conditions that fall outside of Guide parameters and that other institutions may consider feed stability evaluation when addressing challenges with maintaining Guide parameters in feed storage spaces.
From the Archives, in Recognition of the 75th Anniversary of AALAS: Advances in Animal Care Technology at the National Center for Toxicological Research (1976).
Otto G
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683656 · Full text
Abstract loading — click title to view on PubMed.
Spontaneous Benign Thymoma in a 10-Week-Old Female ICR (CD-1) Mouse.
Kim D, Park SH, Sung M … +2 more , Lee HK, Lee S
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683655 · Full text
Thymomas are tumors originating from thymic epithelial cells and are uncommon in animals, including pets and domestic and laboratory animals. A 10-wk-old female ICR (CD-1) mouse in the control group of a toxicity study p...
Thymomas are tumors originating from thymic epithelial cells and are uncommon in animals, including pets and domestic and laboratory animals. A 10-wk-old female ICR (CD-1) mouse in the control group of a toxicity study presented a thymic mass consisting of epithelial and lymphocytic components. Histopathological evaluation showed epithelioid neoplastic cells intermixed with small lymphocytes and areas of hemorrhage. Immunohistochemistry revealed positivity for proliferating cell nuclear antigen and pan-cytokeratin (AE1/AE3), and negativity for S100 and vimentin. Based on these features, the mass was diagnosed as a benign thymoma. To the best of our knowledge, this is the first report of a thymoma in a laboratory mouse at such a young age.
Using Machine Learning and Predictive Artificial Intelligence to Determine Cage Change Frequency for Mice Housed in Individually Ventilated Cages and Drive Vivarium Operational Efficiency.
Collins JM, Singh B, Zwick ME … +4 more , Rosati G, Rigamonti M, Urdiales C, Eswaraka JR
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683654 · Full text
A standard 2-wk cage change frequency for individually ventilated mouse cages is used in many research facilities, with negligible effects on animal health and welfare. However, these techniques rely on subjective visual...
A standard 2-wk cage change frequency for individually ventilated mouse cages is used in many research facilities, with negligible effects on animal health and welfare. However, these techniques rely on subjective visual evaluations and often require spot changes. In this study, we describe the use and validation of digital monitoring technology to objectively determine the necessity of a cage change for mice. We used a machine learning/artificial intelligence algorithm that was trained by annotating human observations of soiled bedding to correlate with the Bedding Status Index (BSI), a digital measure quantifying bedding 'wetness.' Training of the algorithm was performed using various mouse strains of different age, sex, and cage densities to account for variability of these factors. Through constant user feedback and increased datasets, we were able to identify soiled cages with an accuracy >90% for cages with higher densities (for example, 5 animals per cage), while lower densities exhibited slightly reduced accuracy levels (the lowest accuracy was attributed to single-housed mice, at 76%). Our data show that the average change intervals for most average-sized mice ranged between 3 and 6 wk depending on the number of animals in the cage, which is significantly different from the standard 2-wk change used in our facility. Retired breeders and larger mice tended to have a shorter cage change interval as determined by the algorithm. These results show that the Bedding Status Index, which measures an intracage environmental variable, namely bedding wetness, can be used as a marker for cage change. The extended cage change schedule did not affect intracage ammonia, CO2 levels, mouse growth rates, or circadian rhythm metrics. Using digital alerts to determine the need for a cage change resulted in a 65% to 70% reduction in the number of cage changes needed, indicating that this method can improve operational efficiency by reducing cage changes, cage wash time, staff labor, and resource consumption.
Animals in Teaching and Research in the Americas: Analysis of Legislation.
Penha JCQ, Cruz ACM, Castro HC
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683653 · Full text
The use of animals in teaching and research dates back over 2,000 y BCE. However, animal protection laws and regulatory agencies only emerged in the 19th century CE. This study provides a qualitative comparative analysis...
The use of animals in teaching and research dates back over 2,000 y BCE. However, animal protection laws and regulatory agencies only emerged in the 19th century CE. This study provides a qualitative comparative analysis of legislation related to the use of animals in teaching and research activities across 35 American countries. The research evaluated key aspects, including the direct or indirect constitutional recognition of animal protection, the presence of specific or general laws, the establishment and regulation of animal care and use committees, adherence to the 3Rs (Replacement, Reduction, and Refinement) principle, and requirements for facilities, animal care, and personnel. The results revealed significant heterogeneity in regulatory frameworks, with only a few countries having specific laws (8 out of 35), while most rely on general animal protection laws (32 out of 35), with or without specific provisions on the subject. Animal care and use committees, despite their importance, are not universally mandatory, and their regulatory structures vary widely, with legislation explicitly regulating them found in only 9 of the 35 countries analyzed. The 3Rs principle is present in most countries, with "refinement" being the most commonly observed, followed by "replacement" and "reduction." In addition, legal provisions regarding requirements for facilities, housing and care of animals, and personnel responsible for their use and welfare were largely absent in the legislation analyzed, often supplemented by nonmandatory international guidelines. This study highlights the need for standardized regulations that can help achieve animal welfare, maintain ethical practices, and promote greater consistency in oversight mechanisms across the Americas.
Ultrasonography as an Early Evaluation Tool for Posttraumatic Osteoarthritis in Wistar Rats (Rattus norvegicus).
Maldonado Gomes E, Ribeiro DDM, Dos Santos EAP … +5 more , Collares LPP, Bazzan LAJ, Rios Lima Machado I, Oliveira MT, de Arruda Mestieri ML
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683652 · Full text
The aim of this study was to investigate the potential utility of ultrasound in identifying and evaluating early changes in hyaline cartilage during the development of posttraumatic osteoarthritis. To this end, the carti...
The aim of this study was to investigate the potential utility of ultrasound in identifying and evaluating early changes in hyaline cartilage during the development of posttraumatic osteoarthritis. To this end, the cartilages of the medial and lateral femoral condyles of the left and right hindlimbs of 42 male Wistar rats were evaluated by high-frequency ultrasound. The evaluations were carried out at 2 different times: prior to induction of osteoarthritis (US0) and 30 d after surgical rupture of the cranial cruciate ligament (US1) in the left stifle. The right stifle was considered the untreated control joint. Three regions of interest were measured in each cartilage, and the average value obtained was used for statistical comparison. Furthermore, ultrasound images of the left hindlimb were evaluated for the presence of changes in its structure. Cartilages of the left hindlimbs showed a significant increase in measurements obtained at US1 when compared with US0 measurements. On the other hand, the cartilages of the right hindlimbs, used as controla, did not show changes in thickness. Also, in US1, 109 of 168 structural changes, such as loss of hypoechoic characteristic, irregularity in the superficial edge of the cartilage, loss of surface sharpness, and subchondral bone irregularity, were observed in the cartilages of the left medial femoral condyle and 103 of 168 in the lateral cartilages. Therefore, the present findings corroborate the potential utility of high-frequency ultrasound evaluation for detecting and quantifying initial lesions in hyaline cartilage resulting from osteoarthritis.
Comparative Safety and Efficacy of Extended-Release Buprenorphine Formulations for Mouse Reproductive Surgeries under Tribromoethanol.
Gillis-Smith SR, Umana E, Chavarria TE … +2 more , Fabian NJ, Erdman SE
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683651 · Full text
Extended-release buprenorphine formulations are commonly used to control postoperative pain in rodents with minimal handling-related stress. An FDA-indexed formulation is now available that has been demonstrated safe and...
Extended-release buprenorphine formulations are commonly used to control postoperative pain in rodents with minimal handling-related stress. An FDA-indexed formulation is now available that has been demonstrated safe and effective with ketamine-xylazine and isoflurane anesthesia; however, safe use in combination with tribromoethanol, a nonpharmaceutical-grade anesthetic sometimes favored for short, high-volume procedures, has not been reported. Effects on pregnancy and offspring have also not been examined. In this study we compared the safety and efficacy of the FDA-indexed formulation at the labeled dose (3.25 mg/kg) to the compounded extended-release buprenorphine formulation used by the centralized Transgenic Core at our institution at the manufacturer-recommended dosage (1 mg/kg) in CD-1 mice under tribromoethanol anesthesia. A pilot (n = 5 females per drug) was initially conducted with anesthetic and analgesic in the absence of surgical manipulation, after which the formulations were compared in embryo transfer and vasectomy surgeries (n = 10 males or females per drug). Relative efficacy was assessed at 6, 24, 48, and 72 h after surgery using a cageside ethogram, frequency of rearing behavior compared with baseline, and weight change. No differences were seen between analgesic treatment groups. Safety was evaluated by intraoperative respiratory rate, recovery time, incidence of analgesic injection site lesions, and gross necropsy. Ulceration was only observed at the injection site of mice receiving compounded drug; no other differences between treatments were observed. Effects on pregnancy were evaluated by comparing pregnancy success, litter size, and pup weight at weaning between treatment groups in the initial experiment and embryo transfers subsequently performed by the Transgenic Core (n = 19 sets). No significant differences were identified. These results indicate that both formulations can be safely used in vasectomy and embryo transfer surgeries under tribromoethanol anesthesia; however, the FDA-indexed product may improve welfare by decreasing injection site ulceration compared with the compounded formulation.
Effects of Dietary Restriction on Regulation of Energy Metabolism in Male Wistar Rats (Rattus norvegicus).
Kasanen IHE, Inhilä KJ, Nevalainen TO … +2 more , Scheinin M, Savontaus E
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683650 · Full text
Laboratory rats are most often fed ad libitum (AL), but dietary restriction (DR) is commonly used to provide appropriate experimental designs. The current methods of DR have shortcomings; animals are often subjected to s...
Laboratory rats are most often fed ad libitum (AL), but dietary restriction (DR) is commonly used to provide appropriate experimental designs. The current methods of DR have shortcomings; animals are often subjected to social isolation, periods of fasting, and disturbed diurnal eating rhythms. The diet board was developed to solve these problems. The diet board offers the possibility of combining group housing with moderate DR without disturbing diurnal eating rhythms or subjecting animals to periods of fasting. In this study, the diet board's validity as a DR method was investigated by assessing possible endocrine effects associated with the previously observed decreases in weight gain and adiposity. Male Wistar rats (n = 30/group) were housed in groups of 3 and fed either with the diet board or AL over a 10-wk study period. Serum ghrelin, leptin, insulin, and adiponectin concentrations and liver triglyceride content and their variance were measured at the end of the study. The diet board showed no reduction potential in energy metabolism parameters. In the serum levels of the adiposity-related hormones leptin, insulin, and adiponectin or liver triglycerides, no statistically significant differences were found. In contrast, levels of ghrelin were significantly lower in the DR rats compared with the controls. In conclusion, diet board feeding induces mild hormonal compensatory changes, thus offering an alternative method of moderate DR in group-housed rats.
Behavioral Assessment of Tramadol and Meloxicam Effects on Postoperative Pain in a Rat Craniotomy Model.
Alemán-Laporte J, Alvarado G, Pellagio NB … +5 more , Fonseco Brasil Antiorio AT, Zanatto DA, Fornaguera J, Carvajal MRM, Mori CMC
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683649 · Full text
Stereotaxic surgery is a common procedure in neuroscience, yet effective analgesic protocols require further study and refinement to optimize the analgesia used in invasive procedures and to improve animal welfare. This...
Stereotaxic surgery is a common procedure in neuroscience, yet effective analgesic protocols require further study and refinement to optimize the analgesia used in invasive procedures and to improve animal welfare. This study evaluated the effects of tramadol and meloxicam, alone or combined, on pain management following craniotomy in rats. Forty Wistar-Han rats were divided into 5 groups: saline + anesthesia (SAL+ANE), saline + surgery (SAL+SUR), tramadol + surgery (TRA+SUR), meloxicam + surgery (MEL+SUR), and tramadol/meloxicam + surgery (TRA/MEL+SUR). Treatments (saline, 0.2 mL; tramadol, 17.8 mg/kg; meloxicam, 1.5 mg/kg) were administered subcutaneously every 12 h for 72 h. The animals underwent anesthesia or surgery 30 min after the first injection. Postoperative assessments included open field testing, a grooming transfer test, nesting behavior, body weight, and food/water intake. Surgery induced behavioral changes occured within 48 h. SAL+SUR and MEL+SUR groups showed increased locomotion and rearing, while SAL+SUR, TRA+SUR, and TRA/MEL+SUR groups had reduced grooming. TRA/MEL+SUR and SAL+SUR groups had the lowest grooming transfer test scores, and TRA/MEL+SUR rats displayed reduced nesting behavior. Craniotomy caused mild pain lasting at least 48 h. Although no optimal analgesic was identified, providing analgesia and refining surgical techniques are essential to ensure animal welfare.
The Veterinary Consortium for Research Animal Care and Welfare Survey on Revisions to the Eighth Edition of the Guide for the Care and Use of Laboratory Animals.
Storves KP, Talcott MR, Wallace JM … +8 more , Bennett BT, Makaron LM, Clemons D, Hugh Chip Price V, Cohen JK, Hasenau JJ, Freed CK, Leland SE
J Am Assoc Lab Anim Sci · 2025 May · PMID 40683648 · Full text
The Veterinary Consortium for Research Animal Care and Welfare (VCRACW or Consortium) was established in 2019 to provide accurate information to the public, lawmakers, and the scientific community about the veterinary ca...
The Veterinary Consortium for Research Animal Care and Welfare (VCRACW or Consortium) was established in 2019 to provide accurate information to the public, lawmakers, and the scientific community about the veterinary care and welfare of research animals. The consortium includes 2 representatives from 4 member organizations: AALAS, American College of Laboratory Animal Medicine (ACLAM), Association of Primate Veterinarians (APV), and American Society of Laboratory Animal Practitioners (ASLAP). As time for revision of the Guide for the Care and Use of Laboratory Animals (Guide) approaches, the Consortium sought to conduct a survey of the animal research community with the goal of generating objective data and providing analysis that would identify priorities for updating the Guide. An initial survey was conducted of stakeholders from the 4 member organizations. "Chapter 3 Environment, Housing, and Management" was identified as most in need of revision. The "Terrestrial Housing" section was ranked most in need of revision, followed by the "Terrestrial Environment" and "Terrestrial Management" sections, all from Chapter 3. Of the top ten topics the respondents identified that needed revision, 9 were from Chapter 3. Open-ended questions asked respondents to describe key issues that needed to be revised and what new topics should be added, including references. Most responses (199) related to the revision of Chapter 3 and focused on space requirements and environment. New topics proposed for inclusion ranged from additional information on ferrets, agricultural species, and cephalopods to new sections on mental health for employees and study design and additional information pertaining to operations. As a follow-up to the original survey, 5 additional questions were posed to ACLAM diplomates and National Association for Biomedical Research (NABR) members. These questions focused on topics that came from responses to and discussion about the original survey. These topics included the use of must, should, and may; inclusion of additional species; inclusion of mental health topics; future format; and funding source for the Guide. The results of both surveys are presented here. The Consortium believes that these data could be used to refine and revise portions of the Guide to ensure it remains the most current and relevant reference document for the care and use of research animals.
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