Objective To explore the potential mechanisms of hypoxic adaptive metabolic changes in the kidneys of plateau pikas at different altitudes using non-targeted metabolomics analysis via ultra-high-performance liquid chromatography coupled with quadrupole electrostatic field orbital trap-mass spectrometry (UHPLC-QE-MS). Methods 10 plateau pikas were captured at an altitude of 4 360 m in Xingxiuhai area, Maduo County, Guoluo Tibetan Autonomous Prefecture, Qinghai Province (MD group), and 10 plateau pikas were captured at an altitude of 2 900 m in Menyuan area, Haibei Tibetan Autonomous Prefecture, Qinghai Province (MY group). After anesthesia, serum samples were collected, and kidney samples were collected after euthanasia. General physiological and biochemical indicators were measured and metabolomics analysis was performed. Part of the serum samples was used for hematology analysis, another part for blood gas analysis, and the remaining part for biochemical indicator detection. Metabolites were extracted from the kidney tissue samples and then analyzed using UHPLC-QE-MS. Differential metabolites were analyzed using metabolomics principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA), with screening criteria set as variable importance in projection (VIP)>1.5 and fold change (FC)>1.5, or VIP>1.5 and FC<1/1.5. Correlation analysis heatmaps, significance analysis volcano plots, signaling pathway recognition bubble charts, and rectangular graphs were used for the analysis of differential metabolites and related signaling pathways. Results The red blood cell count, glucose, urea nitrogen, uric acid, and homocysteine levels in the MD group plateau pikas were higher than those in the MY group, while hemoglobin, hematocrit, creatinine, and carbon dioxide combining power were lower than those in the MY group. This indicated a significant difference in the blood oxygen-carrying capacity of plateau pikas at different altitudes. The principal component pattern recognition analyses, and OPLS-DA permutation test showed that the kidney metabolites of the MD and MY groups of plateau pikas had distinct clustering distributions (R2Y=0.930, Q2=0.655). According to the screening criteria and database comparison, 46 differential metabolites were identified in the kidneys of plateau pikas at different altitudes. In the MD group of plateau pikas, the expression levels of bufadienolide, adenosine, adenine, diosgenin, berberine chloride, carnosol, and astaxanthin were significantly increased (VIP>1.5, P<0.05), while the levels of arachidonic acid, histamine, and coumarin were significantly decreased (VIP>1.5, P<0.05). The analysis of related signaling pathways showed that the biosynthetic pathways of valine, leucine, and isoleucine had the largest impact factors (P<0.05), while the biosynthetic pathways of pantothenate and coenzyme A showed the most significant enrichment (P<0.05). Conclusion The differential metabolites of amino acids, pantothenate, and coenzyme A pathways in the kidneys of plateau pikas at different altitudes may be involved in the metabolic mechanisms of plateau pikas' hypoxia adaptation in high-altitude environments.

Objective To investigate the spontaneous premature cardiac aging in SHJH ^hr mice. Methods A comparative study was conducted between SHJH ^hr mice (SHJH ^hr group) and wild-type ICR mice (WT group) at different ages (10 and 24 weeks). Cardiac function was analyzed using a small animal in vivo ultrasound imaging system. After euthanasia, organs were collected and weighed to assess the extent of cardiac atrophy. Cardiac pathological damage was observed using hematoxylin-eosin (HE) staining. Cardiac fibrosis was analyzed using Masson staining. Myocardial cell area was analyzed after wheat germ agglutinin (WGA) staining. The activities of oxidative damage indicators in myocardial tissue, including superoxide dismutase (SOD), glutathione peroxidase (GPX), and catalase (CAT), as well as the content of 8-hydroxy-2'-deoxyguanosine (8-OHdG), were measured using enzyme-linked immunosorbent assay. Real-time fluorescence quantitative PCR was used to measure the mRNA expression levels of factors associated with inflammation, fibrosis, and oxidative stress. Colorimetric assay was used to measure malondialdehyde (MDA) levels. Results Compared to WT group mice of the same age, 10-week-old mice in the SHJH ^hr group showed no significant differences in stroke volume (SV), ejection fraction (EF), fractional shortening (FS), or heart and lung weights. However, at 24 weeks of age, mice in the SHJH ^hr group had significantly lower SV, EF, and FS values compared to mice of the same age in the WT group (P<0.05), with no significant change in lung weight but a significant reduction in heart weight (P<0.05). Histological analysis of heart tissue from 24-week-old mice revealed no significant difference in cardiac fibrosis levels between SHJH ^hr and WT groups, but WGA staining showed a significant reduction in myocardial cell area in mice in the SHJH ^hr group (P<0.05). PCR analysis revealed a significant downregulation of mRNA levels of oxidative stress factors Sod2, Gpx1, and Cat genes (P<0.05). Biochemical assays indicated significantly reduced activities of oxidative damage-related enzymes SOD, GPX, and CAT in myocardial tissue (P<0.05), while the levels of oxidative damage markers 8-OHdG and MDA significantly increased (P<0.05). Conclusion Mice in the SHJH ^hr group exhibit premature cardiac aging, which may be associated with oxidative stress damage in myocardial tissue.

Objective To explore the polymorphism of tyrosinase (TYR) and melanocortin 1 receptor (MC1R) genes and their mRNA expression levels in relation to coat-color phenotypes in guinea pigs, providing genetic markers for locating dominant traits in guinea pigs. Methods A total of 57 self-bred ordinary-level guinea pigs were selected and divided into three groups based on coat color: white (n=22), variegated (n=22) and black (n=13). The guinea pigs were euthanized with an overdose of pentobarbital sodium via intraperitoneal injection. DNA was then extracted from the dorsal skin tissue. Polymorphism in the coding sequence (CDS) of the exons of the TYR and MC1R genes in each group was detected by cloning and sequencing. The mRNA expression of the two genes in skin tissues was detected by real-time fluorescent quantitative PCR to investigate the relationship between these genes and guinea pig coat color. Results A single nucleotide polymorphism (SNP) site was found in the CDS region of TYR exon Ⅰ, where the base A was replaced by G. All white guinea pigs had the G/G genotype for TYR, while no deep-colored (variegated and black) guinea pigs exhibited the G/G genotype for TYR. Most deep-colored guinea pigs had the A/A genotype, and a few had A/G genotype. The A/A genotype frequency in black guinea pigs was higher than in variegated guinea pigs. A 2 760 bp sequence deletion was identified in the exon of the MC1R gene, marked as the - gene, with non-deleted samples marked as N gene. Most white guinea pigs had the -/- genotype for MC1R, variegated guinea pigs mainly had the -/N genotype, and black guinea pigs mainly had the N/N genotype, with a few showing the -/N. The TYR gene expression level was higher in white guinea pigs, lower in variegated guinea pigs, and intermediate in black guinea pigs, but there was no significant difference among the three groups (P>0.05). The MC1R gene expression level in white guinea pigs was extremely low, while both variegated and black guinea pigs showed significantly higher levels than white guinea pigs (P<0.01). Black guinea pigs showed significantly higher levels than variegated guinea pigs (P<0.05). Conclusion The TYR and MC1R genes synergistically regulate coat color of guinea pigs. The G-site mutation in the TYR gene may lead to albinism, and the change of N-site in the MC1R gene affects the depth of the coat color.

Objective This study aims to investigate the dynamic changes in general body parameters, blood glucose, and blood lipid profiles in obese cynomolgus monkeys, exploring the correlations among these parameters and providing a reference for research on the obese cynomolgus monkey model. Methods 30 normal male cynomolgus monkeys aged 5 - 17 years old (with body mass index < 35 kg/m2 and glycated hemoglobin content < 4.50%) and 99 spontaneously obese male cynomolgus monkeys (with body mass index ≥35 kg/m2 and glycated hemoglobin content < 4.50%) were selected. Over a period of three years, their abdominal circumference, skinfold thickness, body weight, body mass index, fasting blood glucose, glycated hemoglobin, and four blood lipid indicators were monitored. The correlations between each indicator were analyzed using repeated measurement ANOVA, simple linear regression, and multiple linear regression correlation analysis method. Results Compared to the control group, the obese group exhibited significantly higher levels of abdominal circumference, skinfold thickness, body weight, body mass index, and triglyceride (P＜0.05). In the control group, skinfold thickness increased annually, while other indicators remained stable. Compared with the first year, the obese group showed significantly increased abdominal circumference, skinfold thickness, body weight, body mass index, triglyceride, and fasting blood glucose in the second year(P＜0.05), with this increasing trend persisting in the third year (P＜0.05). In the control group, the obesity incidence rates in the second and third years were 16.67% and 23.33%, respectively, while the prevalence of diabetes remained at 16.67%. In the obese group, the diabetes incidence rates were 29.29% and 44.44% in years 2 and 3, respectively. Among the 11-13 year age group, the incidence rates were 36.36% and 44.68%, while for the group older than 13 years, the rates were 28.13% and 51.35%. Correlation analysis revealed significant associations (P＜0.05) between fasting blood glucose and age, abdominal circumference, skinfold thickness, body weight, and triglyceride in the diabetic monkeys. Conclusion Long-term obesity can lead to the increases in general physical indicators and fasting blood glucose levels in cynomolgus monkeys, and an increase in the incidence of diabetes. In diabetic cynomolgus monkeys caused by obesity, there is a high correlation between their fasting blood glucose and age, weight, abdominal circumference, skinfold thickness, and triglyceride levels, which is of some significance for predicting the occurrence of spontaneous diabetes.

Objective To employ Helicobacter hepaticus (H.hepaticus, H.h) to induce intestinal fibrosis in vitamin D receptor deletion (VDR^-/-) mice, thereby establishing a model of inflammatory bowel disease to investigate its pathological characteristics and underlying mechanisms. Methods Five male WT and five male VDR^-/- mice were orally administered a suspension containing 2×10⁸ CFU of H.hepaticus (referred to as the WT+H.h group and the VDR^-/-+H.h group, respectively), with treatments occurring every other day for three administrations. Concurrently, two uninfected control groups were established, consisting of five WT and five VDR^-/- mice, which were administered an equivalent volume of PBS. Seven days after the final administration, the infection status of the mice was assessed, and their body weight was recorded weekly. At the 16^th week post-infection, the mice were dissected, and the length of the colon tissue was measured, with fecal moisture content analyzed. The colon tissue was partitioned into four parts: one for paraffin embedding for HE, alcian blue-periodic acid Schiff (AB-PAS), Masson's trichrome staining, and immunohistochemical analysis; one for DNA extraction to evaluate the colonization levels of H.hepaticus through real-time fluorescent quantitative polymerase chain reaction (RFQ-PCR), thereby assessing the impact of the infection; one for RNA extraction to analyze cytokine expression via reverse transcription-PCR (RT-PCR); and one for protein extraction to measure the expression levels of alpha smooth muscle actin (α-SMA) and interleukin (IL)-33 using Western blotting. Results All mice in the infected groups successfully were infected with H. hepaticus after three oral gavages. Compared to VDR^-/- control group, VDR^-/- mice exhibited significant weight loss (P<0.05), intestinal hemorrhage, and higher fecal water content after 16 weeks of H. hepaticus infection than the uninfected control group and the WT+H.h group (P<0.05). Compared to the WT+H.h group, HE staining of the VDR^-/-+H.h group showed inflammatory cell infiltration, AB-PAS staining revealed irregular atrophy of intestinal glands and reduced acini, and Masson staining showed increased collagen area. RT-PCR demonstrated that the transcription levels of inflammation and fibrosis-related genes, including IL-6, IL-33, tumor necrosis factor-α (TNF-α), and α-SMA (P < 0.000 1), were significantly upregulated in the colon tissues of VDR^-/-+H.h group. Additionally, immunohistochemical analysis and Western blotting showed that the protein expression levels of IL-33 and α-SMA were markedly increased (P<0.001) in the VDR^-/-+H.h group. Conclusion VDR^-/- mice infected with H.hepaticus exhibit more severe inflammatory responses, including mucosal inflammatory infiltration, impaired mucosal tissue function, and collagen deposition, indicating successful construction of the inflammatory bowel disease model. Further research suggests that VDR deficiency may exacerbate the intestinal fibrosis process associated with inflammatory bowel disease by affecting IL-33 expression.

The ovary has two main functions: folliculogenesis and hormone secretion, both of which are closely related to female fertility. Ovarian aging is characterized by morphological changes, a reduction in follicle numbers, and fluctuations in hormone levels. It not only leads to a decline in female fertility, but is also considered to be a key driver of multi-organ aging. In addition, the disruption of sex hormone secretion associated with ovarian aging can lead to the occurrence of related diseases and symptoms, such as cardiovascular diseases, sleep disorders, and hot flashes. Due to the influence of social pressures and personal career planning, many modern women are increasingly postponing childbearing. However, ovarian aging does not slow down with advancing age. As a result, many women face issues such as infertility when they are ready to have children, having missed their optimal childbearing age. This leads to growing interest in research on delaying ovarian aging. Non-human primates share the closest evolutionary relationship with humans, with a genomic sequence identity of 93%, which grants them unparalleled advantages over other model animals in studies on physiological metabolism, reproductive endocrinology, and developmental aging. Findings obtained in non-human primates are also more reliably translatable to human medical research. This study begins by discussing the current state of ovarian aging research and treatment strategies, highlighting the advantages of non-human primates as laboratory animals for ovarian aging research. It then reviews research progress in areas such as reproductive endocrine hormone levels, ovarian morphology and function, and other physiological changes associated with ovarian aging. Furthermore, it summarizes existing challenges and future research directions, aiming to provide valuable insights for researchers.

Hernia is a common and frequently occurring condition in general surgery, referring to the displacement of an organ or part of an organ from its normal anatomical position through a congenital or acquired weak point, defect, or space into another area. Its pathogenesis is complex, involving multiple factors such as abdominal wall weakness or increased intra-abdominal pressure. The clinical manifestations of hernia vary depending on its type, location, and severity. As the aging of the population continues to advance, the incidence of hernia has been increasing annually. Animal models serve as an important tool in hernia research. They enable the evaluation of the safety and efficacy of new repair materials and techniques, as well as assisting clinicians in developing new surgical methods and investigating the mechanisms and novel therapies for certain hernia diseases and their complications. Given the significant differences in the pathophysiological mechanisms of different types of hernia diseases, the methods and evaluation criteria for establishing animal models are highly diverse. Furthermore, the methods for establishing animal models are closely related to experimental objectives, and different experimental goals require different animal models. Therefore, selecting appropriate animal models based on experimental objectives is crucial for ensuring the smooth progress of research and obtaining reliable results. To this end, this review summarizes effective methods for establishing animal models for external abdominal hernias (including incisional hernia, inguinal hernia, umbilical hernia, parastomal hernia, incarcerated hernia, and pelvic floor hernia), congenital diaphragmatic hernia, hiatal hernia, and cerebral hernia. It provides a detailed analysis of the advantages, disadvantages, and evaluation criteria of these models. Additionally, this review summarizes recent preclinical applications of new hernia repair materials, aiming to provide references for animal experimental research in the field of hernia studies.

Objective To avoid stress responses in experimental monkeys caused by direct capture, and to improve the adaptability and experimental efficiency of marmosets in behavioral, two-photon imaging, and electrophysiological experiments, a device for immobilizing marmosets without the need for capture is developed. Methods A set of compatible transport cage and monkey chair was produced through 3D graphic design and printing. First, the transport cage was aligned with the feeding outlet of the experimental housing cage, and the marmoset was gently guided into the transport cage. Then, the transport cage was connected to the monkey chair, and the marmoset was gently guided into the chair for immobilization. Subsequent experiments were carried out afterward. The effectiveness was evaluated by observing the efficiency of transport and immobilization, the marmoset cooperation level, and stress responses. Results After testing and improvements, the device successfully completed immobilization of marmosets without the need for capture, significantly improving the fluency and efficiency of the experiment. As the number of operations increased, the marmosets became more cooperative, and the operation speed was significantly enhanced. After using the device, the stress responses were noticeably reduced, with marmosets showing lower stress levels. In particular, compared to traditional capture methods, the use of this device significantly reduced marmoset anxiety and discomfort, increasing their cooperation levels during the experiment. Conclusion The monkey chair device designed allows for restraint of marmosets without the need for capture, ensuring smooth progress of subsequent experiments while also safeguarding animal welfare. This device is easy to operate, highly practical, cost-effective, and has great potential for widespread application.

Objective This study aims to investigate the effects of varying durations of light exposure on body weight and learning and memory abilities of pubertal NIH mice. Methods Forty pubertal NIH mice, evenly split by gender and with similar initial weights, were subjected to a 12 h light-dark cycle for one week. They were then randomly assigned to groups with daily light exposure durations of 0, 6, 12, 18, and 24 hours, with 8 mice in each group. The experimental period lasted for 7 weeks, with the first 5 weeks as the feeding phase under different light exposure conditions, and the last 2 weeks as the behavioral testing phase. Their body weight was monitored, and learning and memory abilities were assessed using the T-maze, object location test, and eight-arm maze tests. Results During the light exposure period, there were no significant differences in body weight among groups (P>0.05). However, the weight gain of mice in the 24 h group was significantly higher than that of the 0 h group and the 6 h group during the second and third weeks of light exposure (P<0.05). After five weeks of light exposure, in the T-maze test, the latency time of the 0 h light exposure group was significantly longer than that of the 12 h group (P<0.01), and the latency time of the 24 h light exposure group was significantly longer than that of the 12 h group (P<0.05). In the object location test, the mice in 12 h group exhibited a higher discrimination index and spent more time observing the new location compared to the other groups, with significant differences in comparison to the 18 h group (P<0.01) and the 24 h group (P<0.05). In the eight-arm maze test, the time to find food, the reference memory error rate, and the working memory error rate in the 12 h group were all lower than those in the 0 h group, with significant differences (P<0.05). Moreover, the working memory error rate in the 24 h group was higher than that in the 12 h group, with significant differences (P<0.05). Conclusion Continuous 24 h light exposure affects body weight gain, while light exposure durations exceeding 18 h or below 6 h per day weaken the learning and memory abilities of NIH mice.

Objective The utilization of assisted reproductive technology to rescue genetically modified mouse strains with reproductive disorders provides a reference for improving techniques to preserve valuable experimental mouse strains. Methods In vitro fertilization-embryo transfer (IVF-ET) technology was performed on 28 strains of infertile male mice aged 9-18 months. Several indicators such as sperm density and sperm motility in infertile male mice were assessed to select the most viable sperm for IVF-ET experiments. Fertility rate, abnormal egg rate, and birth rate were recorded after the birth of the pups. An optimized ovarian transplantation procedure was applied to 12 strains of infertile female mice aged 8-18 months. 6-week-old female mice with the same genetic background were selected as recipients. One intact ovary was removed from each recipient mouse, and the contralateral oviduct was ligated. An ovary from a donor mouse was isolated and transplanted orthotopically into the side where the ovary had been removed in the recipient mouse. Twenty-one days post-surgery, recipient mice were co-housed with 8-week-old wild type male mice of the same genetic background for breeding. Data such as the pregnancy rate and live birth rate of the recipients were recorded after the birth of the pups. Results IVF-ET successfully rescued 28 mouse strains, with the oldest male mice being 18 months old. The success rate of the first round of IVF-ET experiments was 89.29% (25/28). The average fertility rate of IVF in infertile male mice was (51.01±14.97)%, the abnormal egg rate was (9.03±5.28)%, and the birth rate of offspring mice was (18.60±7.03)%. 39 out of 40 ovarian transplant recipient mice survived, with a pregnancy rate of 33.33% (13/39) for ovarian transplant recipients, and a live birth rate of 17.95% (7/39). Four mouse strains were successfully rescued using optimized ovarian transplantation technology, with the oldest female mice being 18 months old. 8 strains were not rescued as they failed to produce offspring that survived to sexual maturity. Conclusion IVF-ET is an effective approach for rescuing mice with reproductive disorders caused by different reasons, especially for those beyond the optimal breeding age. Ovarian transplantation technology can also be used as an alternative for aged female mice. But its success rate is relatively lower than that of IVF-ET, and carries a higher experimental risk.

Objective By organizing and implementing a laboratory proficiency validation plan for air change rate testing, this study aims to explore proficiency testing approaches in laboratory animal facilities, assess the current status of relevant laboratories regarding standard application and test capabilities, standardize air change rate testing methods, and ensure the accuracy and reliability of test results. Methods From September to November 2023, the National Institutes for Food and Drug Control (NIFDC) organized a laboratory proficiency validation plan for air change rate testing in laboratory animal facilities (Plan Number: NIFDC-PT-417). The proficiency testing was conducted on-site and consisted of two parts: a written test and practical operation. The written test was open-book. True/false questions focused on participants' understanding of specific clauses in relevant standards, while application-based questions assessed their ability to handle data processing in simulated testing scenarios. The practical operation was conducted according to the relevant criteria of the China National Accreditation Service for Conformity Assessment (CNAS). Two laboratory animal rooms were prepared as proficiency testing samples using a sample splitting approach. These rooms underwent uniformity and stability testing according to CNAS requirements and were approved. Participating laboratories were required to conduct three tests on each of the two laboratory animal rooms, complete the testing and calculation of air change rate within the specified timeframe, and submit their test result reports and original records. Results A total of 27 laboratories registered and participated in the proficiency testing. All participating laboratories submitted their results within the designated timeframe, and the outcomes of all tested laboratories were rated as satisfactory. Conclusion This proficiency validation program objectively and scientifically evaluates the air change rate testing capabilities of selected domestic laboratories, effectively promoting the overall improvement of testing capabilities in the industry. It provides technical support for regulatory authorities to standardize testing institutions and offers reliable references for the purchase of testing services. Through this activity, it was identified that some laboratories need to further enhance their calibration of instruments and the utilization of calibration results. Future efforts should focus on refining related standards to improve the accuracy and reliability of testing.

Laboratory animals are essential in scientific research and experimental teaching in colleges and universities. Disciplines such as life sciences, medicine, pharmacy, chemistry, and biomedical engineering heavily rely on animal experiments. The standardized barrier environmental facility for laboratory animals provides a fundamental platform for stable, scientific, and reliable animal experiment results. Rigorous access management for such facilities is a vital safeguard for maintaining standardized operations of facilities, controlling the quality and stability of laboratory animals, mitigating pathogen contamination risks among animals and laboratory staff, and preventing biosecurity incidents such as zoonotic disease outbreaks. Taking the small-scale barrier facilities for laboratory rats and mice at Nanjing University's Xianlin Campus, operational since 2019, as an example, this study focuses on the safety access management system of these facilities. Based on five years of operational data and accumulated experience in studying and optimizing the access management system, this study, from the perspectives of management system development and the formulation and implementation of standard operating procedures, reviews five aspects of access management: personnel access, animals access, material access, equipment access, and air circulation control. Furthermore, these aspects are systematically analyzed and summarized to serve as a reference for the construction and management of the laboratory animal facilities in universities, while also contributing to scientific research, public health security, and the well-being of experimental personnel.

Animal experiments are essential tools in biomedical research, serving as a bridge between basic research and clinical trials. Systematic reviews and meta-analyses (SRs/MAs) of animal experiments are crucial methods for integrating evidence from animal experiment, which can facilitate the translation of findings into clinical research, reduce translational risks, and promote resource integration in basic research. With the continuous development of the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) methodology, its application in SRs/MAs of animal experiments has gained increasing attention. This article first outlines the principles and specific applications of the GRADE methodology in SRs/MAs of animal experiments, including qualitative descriptive systematic reviews, meta-analyses, and network meta-analyses. It then deeply analyzes the misuse of the GRADE methodology in practice, including incorrect evidence grading, improper classification of evidence, misapplication in qualitative systematic reviews, inconsistencies between the documentation of the upgrading and downgrading process and results, and inappropriate use for making recommendations. Furthermore, this article comprehensively discusses the factors influencing the grading of evidence certainty in SRs/MAs of animal experiments, including the impact of bias risk, indirectness, inconsistency, imprecision, and publication bias on evidence downgrading, as well as the role of large effect sizes and cross-species consistency in evidence upgrading. Finally, in response to the issues discussed, improvement strategies are proposed, including further research and optimization of the GRADE methodology for SRs/MAs of animal experiments, the development of reporting guidelines tailored to the characteristics of SRs/MAs in animal experiment research, and enhanced professional training for researchers in the GRADE methodology. This article aims to improve the quality of evidence in SRs/MAs of animal experiments, strengthen their reliability in clinical decision-making, and promote the more efficient translation of findings from animal experiment research into clinical practice.