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

Sentinel-free soiled bedding (SFSB) is a form of environmental health monitoring that is an efficient method for monitoring rodent colony health. In contrast to direct colony sampling (DCS), when using PCR testing, SFSB can detect both active and past infections and is a less invasive method, classifying it as refinement. In this study, we compared DCS and SFSB for quarantine health monitoring in terms of their effectiveness in detecting pathogens during a 14-day quarantine program. In addition, we performed a time and motion study to examine the time required for each sampling method. We hypothesized that SFSB testing for quarantine would exhibit a greater degree of sensitivity than DCS for the tested pathogen list and take less time to perform. Eleven shipping containers, each containing 4-5 male or female mice aged 6-11 weeks, were subjected to simulated shipping stress as would occur during importation. During the 14-day quarantine, DCS samples included oral swabs, adhesive pelt swabs, and fresh fecal pellets that were pooled per cage and collected on days 0 (baseline) and 7. Each cage was given its own soiled-bedding sampling system, and SFSB samples were comprised of 3 groups: day 0, day 7, and a combination of days 0 and 7. There were no statistically significant differences between the 3 different SFSB sample time points (day 0, day 7, and days 0 and 7 combined) for all pathogens evaluated (P > 0.05). In addition, there were no statistically significant differences between the DCS day 7 and the days 0 and 7 combined SFSB time point for all pathogens evaluated (P > 0.05). Furthermore, SFSB was shown to be less time-consuming than DCS. Thus, SFSB sampling should be considered for quarantine health monitoring programs, as it has similar sensitivity to DCS, is a refinement, and offers a time-saving benefit.

Cryopreservation of pronuclear stage embryos from superovulated mice is beneficial to safeguard genetically modified (GM) mouse strains as well as the efficient production of novel GM mouse strains. C57BL/6J female mice were superovulated with either anti-inhibin serum (AIS) or equine chorionic gonadotropin (eCG), and the resulting oocytes were inseminated via in vitro fertilization (IVF) to produce pronuclear stage embryos. A subset of fresh embryos was cultured in vitro to assess their developmental potential to the blastocyst stage, and the remaining embryos derived from either AIS or eCG superovulation methods were cryopreserved via vitrification and subsequently assessed to determine both in vitro and in vivo developmental competence. The percentage of IVF-derived fresh embryos that developed to 2-cell (92.9 ± 4.1 compared with 92.4 ± 4.2) and the blastocyst stage (91.9 ± 3.84 compared with 91.8 ± 7.9) from eCG and AIS, respectively, was not different (P = 0.89). The percentage of the vitrified pronuclear embryos that were intact after warming for eCG (93.08 ± 5.96) and AIS (88.0 ± 6.63) mice was different (P = 0.039). However, the percentage of IVF-derived vitrified warmed zygotes that developed to 2-cell (82.23 ± 7.18 compared with 83.9 ± 7.22) and the blastocyst stage (71.35 ± 7.76 compared with 74.52 ± 5.57) from eCG and AIS, respectively, was not different. Vitrified pronuclear embryos produced after either AIS or eCG-administered mice were in vitro cultured to 2-cell and surgically transferred into CD-1 surrogate mothers to compare pregnancy rates and live birth rates. There were no differences in percent pregnancy rates between eCG (85.7) and AIS (85.7) superovulation methods. Similarly, there were no differences in the percentage of live offspring between eCG (27.6) and AIS (23.2) superovulation methods. This study suggests that eCG and AIS superovulation methods yield similar in vitro and in vivo embryonic development rates following vitrification, and thus, AIS may be preferred, especially for the strains with difficulty in obtaining large quantities of oocytes or embryos for the production of GM mice or genome banking.

Chronic kidney disease (CKD) is a leading cause of mortality in cats, yet no treatments currently exist to reverse or halt its progression. This lack of therapeutic options stems partly from a limited understanding of the disease pathogenesis and the complexities of its heterogeneous nature. Experimental models of kidney disease are crucial for advancing research and improving treatment outcomes. These models facilitate the identification of biomarkers, elucidate disease mechanisms, and enable the testing of potential therapies. Several feline-specific models, such as ischemia-reperfusion injury (IRI), remnant kidney (RK), and toxin-induced injury (TI), have been developed to study feline kidney disease. Each model has distinct advantages and limitations, making the careful selection of appropriate models critical for progressing research in feline nephrology. The IRI model mimics acute kidney injury that can progress to CKD, while the RK model induces CKD by partially removing kidney tissue, leading to glomerular hyperfiltration. The TI model, involving toxins like meloxicam, provides a simpler approach to studying kidney damage. Despite their utility, these models present challenges, including variability in outcomes, technical demands, and the need for refined methodologies. This review examines the strengths and weaknesses of these feline models and offers recommendations for researchers working to discover new biomarkers and develop effective treatments for CKD in cats.

Chlamydia muridarum has reemerged as a prevalent infectious agent in research mouse colonies. Despite its prevalence and ability to persistently colonize the murine gastrointestinal tract, few studies have evaluated the potential impact of C. muridarum on experimental models of gastrointestinal disease. Studies were conducted to evaluate the impact of C. muridarum on the Citrobacter rodentium, Trichuris muris, and Il10-/- mouse models of intestinal inflammation, as well as on tumorigenesis in the ApcMin/+ mouse following administration of dextran sodium sulfate (DSS). Naïve C57BL/6J (B6), B6.129P2-Il10tm1Cgn/J (Il10-/-), and C57BL/6J-ApcMin/J (ApcMin/+) mice were infected with C. muridarum by cohousing with chronic C. muridarum-shedding BALB/cJ mice for 2 weeks; controls were cohoused with C. muridarum-free mice. After cohousing, B6 mice (n = 8 C. muridarum infected and free) were infected with C. rodentium (109 CFU orally) or T. muris (200 ova orally). Il10-/- mice (n = 8/group with and without Helicobacter hepaticus [108 CFU/mouse] and with and without C. muridarum) and ApcMin/+ mice (n = 8/group) that received 2% DSS for 7 days in drinking water after cohousing. Mice were euthanized 14 days post-C. rodentium infection, 18 days post-T. muris infection, 60 days post-H. hepaticus infection, or control with Il10-/- mice, and 28 days post-DSS administration to ApcMin/+ mice. The severity of the cecal and colonic lesions was evaluated and graded using a tiered, semiquantitative scoring system. C. muridarum infection attenuated colitis associated with C. rodentium (P = 0.03), had no effect on T. muris-associated pathology (P = 0.22), worsened colitis in Il10-/- mice in the absence of H. hepaticus (P = 0.007), and reduced chemically induced colonic tumorigenesis in ApcMin/+ mice (P = 0.004). Thus, C. muridarum colonization differentially impacts several models of intestinal inflammation and tumorigenesis, and the presence of this bacterium in mouse colonies should be considered as a variable in these experimental readouts.

Screening nonhuman primates (NHPs) for tuberculosis (TB) is important to protect the health of NHP colonies and people who interact with them. Screening is especially important for imported NHPs from countries where TB is prevalent and biosecurity practices may be lax. There are a variety of testing methods available for TB screening and diagnosis in NHPs; all have limitations, and their performance in different settings is incompletely characterized. The US Centers for Disease Control and Prevention (CDC) collects TB testing results as part of its regulatory oversight of NHP importation. We collated the results of tuberculin skin tests (TSTs), interferon-γ release assays (IGRAs), multiplexed fluorometric immunoassay (MFIA), Mycobacterium tuberculosis complex PCR, staining for acid-fast bacilli (AFB), and culture of bacteria from tissues for imported NHPs in CDC-mandated quarantine during fiscal years 2021 to 2024. We used these data to assess test performance and intertest agreement for the different tests used. Among 107 imported NHPs tested, TST and IGRA were the most common antemortem tests performed, but they agreed poorly with each other and with culture. AFB staining and PCR exhibited moderate agreement and high positive predictive values using culture as the gold standard. The most commonly affected tissues were lungs and tracheobronchial lymph nodes, regardless of the Mycobacterium sp. identified. Further research is needed to identify and validate additional methods for TB testing in NHPs, particularly for antemortem screening. Tissue acid-fast staining and PCR exhibited high positive predictive values and could be useful to inform policies and clinical decisions about colony management and occupational health while awaiting culture results.

Diarrhea remains the largest disease burden of rhesus macaques in research. Often, the urgency to initiate targeted treatment needs to be balanced with the time needed to accurately diagnose the causative agent. Multiplex PCR gastrointestinal panel testing was compared with conventional fecal culture in a case control study of diarrhea in rhesus macaques. Animals enrolled in the study were from 2 different institutions and 2 different housing environments. Detection of Shigella and Yersinia by fecal culture had higher odds ratios of diarrhea and higher attributable diarrhea risk than did their detection by PCR testing. Multiplex PCR testing had a wider scope of detectable pathogens. The findings of this study provide odds ratios that indicate significant associations between pathogens and diarrhea and attributable diarrhea risk of pathogens that can be ranked relative to each pathogen to provide a guide to clinicians when choosing pathogens to treat with antimicrobials. We have shown that the attributable diarrhea risk of detected pathogens differs depending on which diagnostic method is used, and that our understanding of their detection should be reevaluated when new diagnostics are introduced.

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.

Environmental enrichment is a critical component of a high-quality animal care and use program to provide opportunities for species-specific behaviors and redirect abnormal repetitive behaviors. We used a scoring system to review our enrichment for singly housed mice to assess usage of supplied items. Following the confirmation of utilization of the selected enrichment, we applied the scoring system to address 2 cases of abnormal behavior. Repetitive food shredding in CD-1 mice was reduced by both manzanita sticks and running wheels; however, manzanita sticks were selected for operational ease. Focal auricular trauma associated with ear tags in BALB/c mice was decreased when gnawing items were provided, thus slowing the deterioration of ear tag condition. Scoring for all 3 studies focused on use of the enrichment, incorporation into the nest, or reduction of abnormal repetitive behavior. The development of a scoring system permits the objective assessment and selection of enrichment for unique scenarios, thus enhancing animal welfare and permitting a standardized way to evaluate enrichment for specialized projects.