Journal of the American Association for Laboratory Animal Science : JAALAS最新文献

{"title":"Effects of Nesting Material and Housing Parameters on Feed Wastage Behavior in Female Swiss Webster Mice.","authors":"Zosia E Zawacki, James A Sharpe, Travis C Porco, Krista E Lindstrom","doi":"10.30802/AALAS-JAALAS-24-000010","DOIUrl":"10.30802/AALAS-JAALAS-24-000010","url":null,"abstract":"<p><p>Feed wastage in laboratory mice, also known as chewing or grinding behavior, is problematic for program management and animal welfare. The destruction of pelleted feed without consumption produces a powder accumulation on the cage floor called orts. Ort accumulation disrupts the cage microenvironment and can clog Lixits resulting in flooding. Moreover, added labor adds cost, and cage disruption increases animal stress. Published studies examining the behavior and ways to mitigate it have had inconsistent results, and the cause or causes have not yet been fully identified. The purpose of this study was to identify methods to reduce the development of chewing behavior in laboratory mice. Female Swiss Webster (Tac:SW) mice (<i>n</i> = 144) were randomly assigned to one of 8 groups (12 cages per group) with 2 housing densities (single and pair) and 4 nesting material paradigms. Mice were housed on clean bedding for 8 wk and then soiled bedding for the next 8 wk. Chewing behavior was evaluated by feed weight, cage weight, and feed scores. The addition of a Diamond Twist significantly increased ort production, while nest transfer decreased it but not significantly. Pair housing increased overall orts but not when adjusted for animal number. These results identified potential contributing factors to chewing behavior. However, further research is needed to elucidate the exact causes and solutions.</p>","PeriodicalId":94111,"journal":{"name":"Journal of the American Association for Laboratory Animal Science : JAALAS","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11467877/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142010162","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Examining Intercage Transmission of <i>Chlamydia muridarum</i>: Impact of Barrier Husbandry and Cage Sanitization.","authors":"Michael B Palillo, Noah Mishkin, Mert Aydin, Anthony Mourino, Rodolfo J Ricart Arbona, Neil S Lipman","doi":"10.30802/AALAS-JAALAS-24-043","DOIUrl":"10.30802/AALAS-JAALAS-24-043","url":null,"abstract":"<p><p><i>Chlamydia muridarum</i> (Cm) has reemerged as a prevalent bacterial contaminant of academic research mouse colonies. A study was conducted to assess the effectiveness of husbandry and cage sanitization methods in preventing intercage transmission of Cm. To assess intercage transmission during cage change, a cage housing 2 Cm-free Swiss Webster (SW; Tac:SW) sentinel mice was placed randomly on each of 12 individually ventilated cage racks, housing cages with Cm-shedding mice, located in one of 2 animal holding rooms. Husbandry staff blinded to the study cages changed all cages in the animal holding rooms weekly using a microisolation cage technique. PCR testing performed at 180 d postplacement confirmed all mice remained negative for Cm. To assess the effectiveness of cage sanitization to eliminate Cm, we investigated transmission of Cm to a naive Cm-free SW and NOD.Cg-<i>Prkdc</i>^scid <i>Il2rg^tm1Wjl</i>/SzJ (NSG) mouse cohoused for 7 d (repeated weekly for 4 wk) in cages assigned to one of 3 groups (<i>n</i> = 10 pairs of mice/group). Cages that previously housed 2 Cm-shedding BALB/c mice were either washed in a tunnel washer (82.2 °C [180 °F] final rinse for an average of 16 s per run; <i>n</i> = 10) with and without postwashing autoclaving (121 °C for 20 min; <i>n</i> = 10), or were untreated (bedding change only; <i>n</i> = 10). Pre- and postsanitization swabs of each cage were assayed for Cm by PCR. All pretreatment swabs tested positive, while posttreatment swabs from all cages (excluding bedding change) tested negative. All SW and NSG mice, irrespective of group, remained negative for Cm as determined by PCR. These findings suggest that infectious Cm does not persist in untreated cages or after mechanical washing with and without autoclaving. Collectively, these findings suggest that neither our husbandry protocols nor inadequate cage sanitization methods likely contributed to the observed prevalence of Cm in contemporary research mouse colonies.</p>","PeriodicalId":94111,"journal":{"name":"Journal of the American Association for Laboratory Animal Science : JAALAS","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11467882/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141997138","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Voluntary Wheel Running an Effective Intervention in the Management of Excessive Food Usage in CD-1 Mice (<i>Mus musculus</i>).","authors":"Alexis M E Skurnack, Shawn P Lane, Lori Garman, Amy L Burke, Wendy R Williams, Madeline L Budda","doi":"10.30802/AALAS-JAALAS-24-040","DOIUrl":"10.30802/AALAS-JAALAS-24-040","url":null,"abstract":"<p><p>Some mice demonstrate excessive food-grinding behaviors in which food pellets are broken down into crumbs (orts). This is considered abnormal behavior and is undesirable in a research environment, as it is thought to potentially be a stereotypic behavior suggestive of a negative welfare state in these animals. Further, food grinding often necessitates more frequent food and bedding changes. Research outcomes may also be affected if investigators do not exclude food losses due to grinding when measuring food consumption. We hypothesized some mice may excessively grind food in part to expend energy and access to a running wheel would contribute to a reduction in food grinding. Total daily food usage (the combined weight of food consumption and ort production) was measured for 40 d in CD-1 mice that exhibited food grinding. Median daily food usage was compared 10 d before, 20 d during, and 10 d after access to a running wheel. Additional cages of similar food-grinding mice that did not have access to a running wheel were monitored during the same period for comparison. A significant reduction in food usage was observed in 8 out of the 20 d in which mice had access to a running wheel compared with controls (<i>P</i> < 0.05). This reduction was significantly less than the median daily food usage before and after the running wheels were available (<i>P</i> < 0.01). Food usage significantly increased sharply in the 3 d following removal of the running wheel compared with controls during the same period (<i>P</i> < 0.05). A positive correlation between relative humidity and median daily food usage was observed (<i>P</i> < 0.05). Despite fluctuations in relative humidity, providing a running wheel effectively reduced excessive food-grinding behavior.</p>","PeriodicalId":94111,"journal":{"name":"Journal of the American Association for Laboratory Animal Science : JAALAS","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11467874/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141984252","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Pharmacokinetics of Injectable Meloxicam and Buprenorphine in the Naked Mole-Rat (<i>Heterocephalus glaber</i>).","authors":"Caileen R Moran, Thomas J Park, Rochelle Buffenstein, Sayan Chakrabarty, Matthew O Lindeblad, Jeffrey D Fortman, Cynthia R Adams","doi":"10.30802/AALAS-JAALAS-24-045","DOIUrl":"10.30802/AALAS-JAALAS-24-045","url":null,"abstract":"<p><p>Unique characteristics of the naked mole-rat (NMR) have made it increasingly popular as a laboratory animal model. These rodents are used to study many fields of research including longevity and aging, cancer, circadian rhythm, pain, and metabolism. Currently, the analgesic dosing regimens used in the NMR mirror those used in other rodent species. However, there is no pharmacokinetic (PK) data supporting the use of injectable analgesics in the NMR. Therefore, we conducted 2 independent PK studies to evaluate 2 commonly used analgesics in the NMR: meloxicam (2 mg/kg SC) and buprenorphine (0.1 mg/kg SC). In each study, blood was collected at 8 time points after subcutaneous injection of meloxicam or buprenorphine (0 [predose], 0.25, 0.5, 1, 2, 4, 8, and 24 h). Three NMRs were used per time point for a total of 24 animals per PK study. Plasma concentrations of meloxicam were highest between 0.5 and 1 h postinjection. Levels remained above the extrapolated dog and cat therapeutic threshold levels (390 to 911 ng/mL) for at least 24 h. Plasma concentrations of buprenorphine were highest between 0.25 and 0.5 h postinjection. Levels remained above the human therapeutic threshold (1 ng/mL) for up to 21 h. No skin reactions were seen in association with injection of either drug. In summary, these data support dosing meloxicam (2 mg/kg SC) once every 24 h and buprenorphine (0.1 mg/kg SC) once every 8 to 12 h in the NMR. Further studies should be performed to evaluate the clinical efficacy of these drugs by correlating plasma concentrations with postoperative pain assessments.</p>","PeriodicalId":94111,"journal":{"name":"Journal of the American Association for Laboratory Animal Science : JAALAS","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11467880/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141857468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sedation Efficacy of Midazolam in Conjunction with Ketamine and Alfaxalone in Female Laboratory Guinea Pigs (<i>Cavia porcellus</i>).","authors":"Keely Nicole Wharton, Courtney A Walsh, Marlena Haulter, Dinesh Ekanayake, Dil Ekanayake-Alper","doi":"10.30802/AALAS-JAALAS-24-000028","DOIUrl":"10.30802/AALAS-JAALAS-24-000028","url":null,"abstract":"<p><p>Guinea pigs have been integral as models used in biomedical research, making significant contributions to nutritional, auditory, immunologic, and hypersensitivity studies, and necessitating the routine need for sedation in laboratory settings. The ketamine-xylazine (KX) combination has been the standard sedation protocol for decades. However, due to the adverse effects and abuse potential of xylazine, this study explores the possibility of substituting xylazine with midazolam and examines the combined use of midazolam with ketamine and alfaxalone in female laboratory guinea pigs. Our findings indicate that KX facilitates the fastest induction and longest duration of sedation compared with other sedatives, including ketamine-midazolam (KM), which, despite its rapid induction, results in significantly shorter sedation durations. KX also ensures a deeper anesthetic depth and greater odds of loss of withdrawal and inguinal reflexes, in contrast to KM and alfaxalone-midazolam (AM), under which only 15% of the animals lost these reflexes. In terms of cardiopulmonary function, KM led to an increased heart rate attributed to elevated sympathetic activity. All 4 sedative protocols lead to respiratory depression, except KM, which causes minimal reduction. Adverse events varied, with 75% of animals experiencing injection site reactions after KX administration and 67% exhibiting regurgitation post-KM administration. No adverse events were reported for the AM combination, suggesting its safer profile. In conclusion, while KX remains the superior protocol for sedation due to its efficiency, reliability, and minimal impact on physiologic parameters, midazolam is not a preferable alternative to replace xylazine. Its increased sympathetic tone, hyperesthesia, and shorter action duration, coupled with a higher potential for adverse events, limit its suitability to combine with ketamine in guinea pig sedation. However, when midazolam is used in conjunction with safer alternatives like alfaxalone, it presents a viable sedation strategy, emphasizing the need for further research into optimizing sedative combinations for laboratory guinea pigs.</p>","PeriodicalId":94111,"journal":{"name":"Journal of the American Association for Laboratory Animal Science : JAALAS","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11467886/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141794406","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effects of Intermittent Harem Mating on Parturition-induced Stress and Success Rate of Weaning in C57BL/6JNarl Mice.","authors":"Tsung-Keng Chang, Chih-Hsuan Wang, Tzu-Yi Lin, Yu-Chia Su","doi":"10.30802/AALAS-JAALAS-24-000003","DOIUrl":"10.30802/AALAS-JAALAS-24-000003","url":null,"abstract":"<p><p>Improving the effectiveness of mating schemes for large-scale production of mice is an ongoing challenge in animal facilities. Continuous mating, which requires fewer breeding cages than intermittent mating, has traditionally been used to take advantage of postpartum estrus for efficient production. However, the continuous mating scheme lacks flexibility because it cannot immediately accommodate the reduced needs of mice when production levels are high. In this study, we compared reproductive performance, fecal corticosterone metabolite (FCM) level as a stress indicator, and mouse mortality between the continuous trio (CT) and intermittent quad (IQ) mating schemes. The weaning rates in the IQ scheme were higher than those in the CT scheme (98.8% compared with 85.3%). The FCM levels in IQ female breeders were lower during the first 5 d after parturition than those in CT female breeders. The FCM levels in postpartum females housed with 2 adult mice were significantly higher on days 1, 3, and 5 after giving birth than those of females housed alone. This suggests that the presence of cage mates may induce stress responses in postpartum females. Increasing the individual cage area did not reduce the FCM levels of female breeders when accompanied by cage mates after parturition. In addition, the incidence of dystocia and mortality was lower in IQ breeders than in CT breeders. In summary, this breeding trial suggests that compared with the continuous mating scheme, the intermittent mating scheme improves the welfare of postpartum females with normal breeding performance in the C57BL/6JNarl production colony.</p>","PeriodicalId":94111,"journal":{"name":"Journal of the American Association for Laboratory Animal Science : JAALAS","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11467875/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141768378","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comparison between a Tail Clamp and Electrical Stimulation for Sevoflurane Minimum Anesthetic Concentration Determination in Green Iguanas (<i>Iguana iguana</i>).","authors":"Laura R Ghussn, André A Justo, Mariana C Sanches, Silvia Rg Cortopassi, Adriano B Carregaro","doi":"10.30802/AALAS-JAALAS-23-000124","DOIUrl":"10.30802/AALAS-JAALAS-23-000124","url":null,"abstract":"<p><p>This study aimed to compare the minimum anesthetic concentration (MAC) of sevoflurane in green iguanas using elec- trical stimulation and tail clamping as noxious stimuli. Seven adult green iguanas (<i>Iguana iguana</i>) weighing 580 to 1,300 g were enrolled. Each iguana was anesthetized twice after a 1-week washout period, with MAC being determined using a tail clamp (MACt) or electrical stimulation (MACe ) techniques. After sevoflurane mask induction and endotracheal intubation, the fraction of expired sevoflurane (Fe 'Sevo) was maintained at 3.1% for 15 min before noxious stimulation. In a bracketing design, the subsequent Fe'Sevo values were increased or decreased by 10% after positive or negative responses, respectively. Each targeted Fe 'Sevo was kept constant for 15 min before stimulation. In MACt, the noxious stimulus involved closing a Kelly hemostatic curved forceps to the first ratchet at the base of the tail. At the same site, in MACe, 2 30 × 0.8-mm hypodermic needles inserted 1 cm apart were connected to an electrical stimulator set to deliver 30 mA at 50 Hz at a 6.5-ms interval. The hemostat and the needles were repositioned 2 cm distally and on alternate tail sides at each stimulation round. Individual MAC was obtained when 2 consecutive crossover events occurred (a positive response preceding a negative response or vice versa), with the MAC of each group represented by the average of the individual MAC values. Median (interquartile range) values for the sevoflurane MAC did not differ significantly between groups (2.2 [2.2 to 2.8%] in MACe and 2.2 [1.8 to 3.5%] in MACt ; <i>P</i> = 0.812). Time to anesthesia induction, time to MAC measurement, heart rate (HR), end-tidal carbon dioxide (ET'CO2), and cloacal temperature were not different between groups. Both the tail-clamping and the electrical stimulation techniques yielded resembling sevoflurane MAC values in green iguanas, which makes the tail clamp a reliable alternative to electrical stimulation-based MAC research in this species.</p>","PeriodicalId":94111,"journal":{"name":"Journal of the American Association for Laboratory Animal Science : JAALAS","volume":" ","pages":"418-421"},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11270046/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140066399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Infrared Thermal Imaging during the Estrous Cycle in Adult Wistar Rats.","authors":"Lucia Mihalovičová, Veronika Kunšteková, Dávid Miláček, Andrej Feješ, Mária Tekeľová, Emese Renczés, Peter Celec, Veronika Borbélyová","doi":"10.30802/AALAS-JAALAS-23-000087","DOIUrl":"10.30802/AALAS-JAALAS-23-000087","url":null,"abstract":"<p><p>The collection and examination method of vaginal smears is the standard for the determination of ovulation or phases of the estrous cycle of rodents used in research. However, this method is time consuming and may not be amenable to continual monitoring of a large number of animals. Infrared thermography has recently emerged as a noninvasive technique that requires relatively little handling of animals. The body temperature of rodents has been shown to correlate with the ocular surface temperature. This study aimed to evaluate the use of thermographic monitoring of the ocular surface for the identification of estrus in rats. Vaginal smears were collected from female Wistar rats (<i>n</i> = 22) for 14 consecutive days. Core body temperature was estimated by measuring ocular surface temperature using a thermal camera; vaginal temperature was measured using a digital thermometer. Average temperatures were calculated for each rat for each phase of the estrous cycle. The highest core body and vaginal temperature were measured during the estrus phase (37.2 ± 0.6 °C and 37.7 ± 0.6 °C, respectively). The temperatures then fell as the rat entered the diestrus phase (36.8 ± 0.5 °C and 37 ± 0.5 °C). The core body temperature was positively correlated with vaginal temperature (<i>r</i> = 0.697, <i>P</i> < 0.001). In conclusion, thermography is a less invasive method of determining estrus in rats as compared with vaginal smear collection. However, thermography is less accurate and requires at least a 12-d period of measurement.</p>","PeriodicalId":94111,"journal":{"name":"Journal of the American Association for Laboratory Animal Science : JAALAS","volume":" ","pages":"397-402"},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11270034/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140112544","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Deep Learning for Face Detection and Pain Assessment in Japanese macaques (<i>Macaca fuscata</i>).","authors":"Vanessa N Gris, Thomás R Crespo, Akihisa Kaneko, Munehiro Okamoto, Juri Suzuki, Jun-Nosuke Teramae, Takako Miyabe-Nishiwaki","doi":"10.30802/AALAS-JAALAS-23-000056","DOIUrl":"10.30802/AALAS-JAALAS-23-000056","url":null,"abstract":"<p><p>Facial expressions have increasingly been used to assess emotional states in mammals. The recognition of pain in research animals is essential for their well-being and leads to more reliable research outcomes. Automating this process could contribute to early pain diagnosis and treatment. Artificial neural networks have become a popular option for image classification tasks in recent years due to the development of deep learning. In this study, we investigated the ability of a deep learning model to detect pain in Japanese macaques based on their facial expression. Thirty to 60 min of video footage from Japanese macaques undergoing laparotomy was used in the study. Macaques were recorded undisturbed in their cages before surgery (No Pain) and one day after the surgery before scheduled analgesia (Pain). Videos were processed for facial detection and image extraction with the algorithms RetinaFace (adding a bounding box around the face for image extraction) or Mask R-CNN (contouring the face for extraction). ResNet50 used 75% of the images to train systems; the other 25% were used for testing. Test accuracy varied from 48 to 54% after box extraction. The low accuracy of classification after box extraction was likely due to the incorporation of features that were not relevant for pain (for example, background, illumination, skin color, or objects in the enclosure). However, using contour extraction, preprocessing the images, and fine-tuning, the network resulted in 64% appropriate generalization. These results suggest that Mask R-CNN can be used for facial feature extractions and that the performance of the classifying model is relatively accurate for nonannotated single-frame images.</p>","PeriodicalId":94111,"journal":{"name":"Journal of the American Association for Laboratory Animal Science : JAALAS","volume":" ","pages":"403-411"},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11270042/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140013859","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Determination of Postmortem Interval in Mice.","authors":"Rachel R Howie, Michael M McKinney, Nicholas M Tataryn, Allysa L Cole, William D Dupont, Tzushan S Yang, Katherine N Gibson-Corley","doi":"10.30802/AALAS-JAALAS-23-000107","DOIUrl":"10.30802/AALAS-JAALAS-23-000107","url":null,"abstract":"<p><p>Despite the major use of mice in biomedical research, little information is available with regard to identifying their postmortem changes and using that information to determine the postmortem interval (PMI), defined as the time after death. Both PMI and environmental conditions influence decomposition (autolysis and putrefaction) and other postmortem changes. Severe decomposition compromises lesion interpretation and disease detection and wastes limited pathology resources. The goal of this study was to assess postmortem changes in mice in room temperature cage conditions and under refrigeration at 4 °C to develop gross criteria for the potential value of further gross and histologic evaluation. We used 108 experimentally naïve C57BL/6 mice that were humanely euthanized and then allocated them into 2 experimental groups for evaluation of postmortem change: room temperature (20 to 22 °C) or refrigeration (4 °C). PMI assessments, including gross changes and histologic scoring, were performed at hours 0, 4, 8, and 12 and on days 1 to 14. Factors such as temperature, humidity, ammonia in the cage, and weight change were also documented. Our data indicates that carcasses held at room temperature decomposed faster than refrigerated carcasses. For most tissues, decomposition was evident by 12 h at room temperature as compared with 5 d under refrigeration. At room temperature, gross changes were present by day 2 as compared with day 7 under refrigeration. Mice at room temperature lost 0.78% of their baseline body weight per day as compared with 0.06% for refrigerated mice (95% CI for difference 0.67% to 0.76%, <i>P</i> < 0.0005). This study supports the consideration of temperature and PMI as important factors affecting the suitability of postmortem tissues for gross and histologic evaluation and indicates that storage of carcasses under refrigeration will significantly slow autolysis.</p>","PeriodicalId":94111,"journal":{"name":"Journal of the American Association for Laboratory Animal Science : JAALAS","volume":" ","pages":"428-436"},"PeriodicalIF":0.0,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11270044/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140112543","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}