Objective By simulating acute hypoxic conditions, an experimental model of intestinal stress injury in plateau mice was established to explore the pathogenic mechanism of acute gastrointestinal diseases in plateau, and to lay foundation for preventive and therapeutic measures.MethodsThirty-six SPF-grade adult male BALB/c mice were randomly divided into four groups: normoxic 24 h, normoxic 72 h, hypoxic 24 h, and hypoxic 72 h, based on body weight using a randomized numerical table method, with nine mice in each group. Mice in the normoxic group were kept in a conventional barrier environment, while those in the hypoxic group were placed in a hypoxic chamber within the barrier environment with oxygen concentration set at 10% to simulate plateau conditions. They were subjected to stress for 24 h and 72 h, respectively, in order to establish a model of intestinal injury induced by acute hypoxia. After modeling, the mice were weighed, anesthetized with 1% pentobarbital sodium, and then euthanized by cervical dislocation. Duodenal and colonic tissues were collected. Histopathological morphology of intestinal tissues was observed after HE staining. Western blotting and immunohistochemistry were used to detect the expression levels of tight junction-related proteins in intestinal tissues. Real-time fluorescence quantitative PCR was performed to measure the expression levels of inflammatory cytokines and chemokines. TUNEL staining was used to assess apoptotic activity of intestinal epithelial cells, thus evaluating intestinal injury-related phenotypes in this model.Results Compared with the normoxic groups, mice in the 24 h and 72 h hypoxia groups showed weight loss, shortened duodenal villi, abnormal crypt structure, and decreased villus/crypt ratio. The colonic mucosa was infiltrated with inflammatory cells and irregular crypt structure. Expression levels of Occludin and zonula occludens-1 (ZO-1) were significantly decreased in duodenal and colonic tissues of mice in the 24 h and 72 h hypoxia groups (P<0.05). The expression of pro-apoptotic protein Bax was significantly up-regulated while expression of anti-apoptotic protein Bcl-2 was significantly down-regulated in duodenal tissues (P<0.05). Apoptotic activity of intestinal epithelial cells was significantly enhanced (P<0.05). In addition, interleukin (IL)-1β, IL-6, monocyte chemoattractant protein-1 (MCP-1), and tumor necrosis factor-α (TNF-α) mRNA levels were significantly increased in duodenal tissues after 24 and 72 h of hypoxic stress(P<0.05). After 24 h of hypoxic stress, there was no significant change in the expression levels of inflammatory cytokines in colon tissues (P>0.05), but after 72 h, the expression levels of pro-inflammatory factors IL-1β, TNF-α, IL-6, MCP-1, and anti-inflammatory factor IL-10 mRNAs significantly increased in colon tissues of mice (P<0.05).Conclusion The usage of a hypoxia chamber to simulate an acute hypoxic environment in plateau can lead to abnormal intestinal tissue structure, intestinal barrier dysfunction, and induce intestinal epithelial cell apoptosis, triggering an intestinal inflammatory response in stress mice. These findings indicate the successful construction of a mouse model for an acute hypoxic stress-induced intestinal injury.

Objective The aim is to utilize CRISPR/Cas9 gene editing technology to construct Dmd gene mutant mice with a point mutation in exon 23 of the Dmd gene. Subsequently, the phenotypic changes of the mice in muscles and immune systems are analyzed and verified, providing an evaluation model for Duchenne muscular dystrophy and other related diseases.MethodsBased on the sequence characteristics of exon 23 of the Dmd gene, small guide RNA (sgRNA) was designed and synthesized. Cas9 mRNA, sgRNA fragments, and oligo donor DNA were microinjected into fertilized eggs of C57BL/6J mice. After transferring the fertilized eggs to surrogate mice, F0 generation mice were born. After mating with F0 generation mice, offspring mice were obtained, and Dmd gene positive mutant (Dmd^Mu/+) mice were obtained after genotype identification. Male hemizygous Dmd^Mu/+(Dmd^Mu/Y) mice were selected for phenotype validation. The body weight of live 3- and 9-month-old mice were recorded. Muscle tension was evaluated through the grid test. Hearts and semitendinosus muscles were collected, and the histopathological changes were observed using HE staining. Further, the expression of Dmd protein in muscle tissue of 9-month-old mice was analyzed by Western blotting.An acute inflammation model was established in Dmd^Mu/Y mice using lipopolysaccharide induction. Peripheral blood from the submandibular vein was collected, and the changes in the proportion of neutrophils and monocytes were detected by flow cytometry.Results The results of genome sequencing and Western blotting confirmed the successful construction of Dmd gene point mutant mice (Dmd^Mu/+ mice). Dmd protein expression was not detected in skeletal muscle and myocardium of Dmd^Mu/+ mice, and it was significantly reduced compared to wild-type C57BL/6J mice (P<0.05). Compared with wild-type mice of the same background, Dmd^Mu/Y mice at 3 and 9 months of age showed significant weight loss (P<0.01) and decreased muscle tension (P<0.05). 9-month-old Dmd^Mu/Y mice exhibited significant pathological changes in skeletal muscle and myocardium, including widening of intermuscular space. Under normal condition, compared with wild-type mice, the proportion of neutrophils and monocytes in the peripheral blood of 3-month-old Dmd^Mu/Y mice was significantly lower than that of wild-type mice (P<0.01). After lipopolysaccharide stimulation, the proportion of neutrophils in peripheral blood of 3-month-old Dmd^Mu/Y mice remained significantly lower compared to that of wild-type mice (P<0.01). The proportion of neutrophils in peripheral blood of 9-month-old Dmd^Mu/Y mice significantly decreased after lipopolysaccharide induction (P<0.01), with a trend of change observed in monocytes between groups.Conclusion The successful construction of the Dmd gene mutant mouse model has confirmed the vital function of Dmd gene in maintaining normal muscle tissue morphology and muscle tone. It preliminarily indicated that Dmd gene deletion could significantly reduce the proportion of neutrophils in peripheral blood, offering a new perspective for the study of immune system alterations in Duchenne muscular dystrophy patients.

ObjectiveTo explore the metabolic changes during the development of Tupaia belangeri breast tumors, to investigate the close relationship between the changes of serum metabolic substances and the occurrence and progression of tumors, and to screen for biomarkers reflecting the progression of breast tumors. MethodsBreast tumors in Tupaia belangeri were induced by orally administering 7,12-dimethylbenzoanthracene (DMBA) three times, with a 15-day interval between each administration, along with a high-fat and high-sugar diet. The DMBA-induced breast cancer group and the DMBA-inducedwithout breast cancer group were compared with the control group. Untargeted determination of serum metabolites was performed using gas chromatography-time-of-flight mass spectrometry (GC-TOFMS) in DMBA-induced Tupaia belangeri with breast cancer, DMBA-induced without breast cancer and the control group. Multidimensional statistical analysis including unsupervised principal component analysis (PCA), and orthogonal partial least squares analysis (OPLS-DA) were conducted. Furthermore, t-test was used for intergroup differential comparison. Differential metabolites were screened under VIP>1 and P<0.05 conditions, and significantly changing differential metabolites were identified using the HMDB online database. The Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway database was utilized to enrich metabolic-related gene regulatory pathways. ResultsThe incidence of breast tumors was 40% in DMBA-induced Tupaia belangeri. Compared with the control group, 30 metabolic differential products were detected in the serum of the group with breast cancer, with 18 down-regulated and 12 up-regulated (VIP>1, P<0.05). KEGG pathway analysis revealed significant changes in four metabolic pathways: glutamate metabolism, glyceride metabolism, citric acid cycle, and alanine metabolism. Compared with the group without breast cancer, 18 metabolic differential products were detected, with 7 down-regulated and 11 up-regulated (VIP>1, P<0.05). KEGG pathway analysis revealed significant changes in the citric acid cycle and glutamate metabolism. Compared with the control group, 31 metabolic differential products were detected in the serum of the groups without breast cancer, with 14 down-regulated and 17 up-regulated (VIP>1, P<0.05). KEGG pathway analysis revealed significant changes in three metabolic pathways: glutamate metabolism, glyceride metabolism, and citric acid cycle. ConclusionMetabolomics analysis can reveal the characteristics of changes in metabolites in the serum of breast tumors. The results suggest that glutamate metabolism, glyceride metabolism, citric acid cycle, and alanine metabolism pathways are associated with the occurrence and development of DMBA-induced breast tumors in Tupaia belangeri. It provides a foundation for further research into the biological mechanism of breast cancer.

ObjectiveTo provide more basic information of comparative medicine for the study of biological changes and pathogenesis of COVID-19 by systematical sorting and analyzing the transcriptome data.MethodsFollowing a retrieval strategy, using COVID-19 and SARS-CoV-2 as key words, transcriptome datasets related to COVID-19 from January 2020 to May 2023 were collected from GEO, ArrayExpress and GEN Transcriptome databases. The composition, distribution, and research application of COVID-19 transcriptome data resources were analyzed. Data distribution was visually displayed and correlation analysis was performed. The research applications and limitations of existing COVID-19 transcriptome data were analyzed from the perspectives of clinical medicine and comparative medicine, focusing on clinical-related molecular mechanisms, biomarkers and related immune responses, treatment intervention strategies, etc. The research value and application prospects were discussed.Results A total of 975 sets of COVID-19 transcriptome data were included. Among three databases, datasets from humans accounted for the highest proportion, namely 71.9%, 77.9%, and 90%, respectively. Species other than humans, such as mice, were the main sources of data, with the respiratory and nervous systems having the highest distribution of data. Twenty-seven datasets were associated with clinical significance. Analysis revealed that respiratory tract injury and other related molecular mechanisms were obtained through transcriptome data mining. Biomarkers such as cfDNA could be used as therapeutic targets. The severity of COVID-19 infection was associated with cell changes and disorders represented by M1 macrophages. Comparative medical analysis showed that mice, hamsters, and other animals were susceptible to SARS-CoV-2. Rhesus monkeys and cynomolgus monkeys exhibited infection characteristics highly similar to human. Apart from respiratory symptoms, hamsters also exhibited digestive system symptoms. SARS-CoV-2 can replicate in the respiratory organs of various susceptible animals, the intestines of ferrets and the ears of minks, resulting in interstitial pneumonia, diffuse lung injury and other pathological changes of varying degrees. Based on the differences in immune responses, hamsters can be used for neutralizing antibody reaction research.Conclusion Currently there is a wealth of COVID-19 transcriptome data, but there is a lack of comparative transcriptome research. Transcriptomics can be combined with comparative medicine to further explore the differences in comparative medicine of COVID-19.

Objective To comprehensively analyze the reported preparation methods for animal models of perimenopausal syndrome (PS), to compare the advantages and disadvantages of various preparation elements and detection indexes, so as to provide useful references for the optimization of the relevant animal models as well as the standardization of their application in the efficacy evaluation of new drugs.MethodsIn this paper, literature research methods were applied using "perimenopausal syndrome" as the subject term. The publication period of the literature was limited to January 2016 to February 2023. Relevant literature on the preparation of PS animal models was retrieved from databases such as China National Knowledge Infrastructure, Wanfang database, and PubMed. After screening the experimental literature that met the inclusion and exclusion criteria, detailed information on experimental animal strains, modeling methods, duration of drug administration, positive drugs, detection indexes and other relevant information were collected. After the above information was standardized, the PS animal model database was established using Excel 2010 software. The model preparation elements and evaluation indexes were summarized systematically, and the statistical results were processed and analyzed using Excel 2010 software.Results A total of 247 articles were screened. SD rats (164 times, 65.86%) and Wistar rats (35 times, 14.06%) were often used to prepare PS animal models. Bilateral ovariectomy (139 times, 53.87%) and natural aging (43 times, 16.80%) were chosen as modeling methods. The ages of rats used for modeling ranged from 7 weeks to 18 months, with 3-month-old rats (22 times, 21.78%) being the most common. The detection indexes were comprehensively evaluated from multiple perspectives, including serum biochemistry, vaginal exfoliated cell smear, histomorphology, general observation, behavioral observation, and organ tissue protein immunoblotting. Western medical evaluation indexes were commonly used to test the successful preparation of models, with vaginal exfoliated cell smears being the most frequently used method (125 times, 85.04%). A model was considered successfully prepared when estrous cycle disorder or irregularity was observed. Some literature also determined modeling success by detecting a significant decrease in serum estradiol levels (5 times, 3.04%). Traditional Chinese medicine (TCM) syndrome evaluation often used a combination of Chinese and Western medical evaluation indexes for comprehensive evaluation, with researchers determining the TCM syndrome through vaginal exfoliated cell smears supplemented by general observation (3 times, 2.04%).Conclusion There are many methods for preparing PS animal models, but there are still significant differences in the selection of animal species, age, criteria for successful modeling, and TCM syndrome evaluation in the related literature.

Objective To calculate the leakage rate of the automated watering system in Tsinghua University Laboratory Animal Resources Center, to evaluate the safety of the system, and provide references for selection, maintenance, and management of automated watering systems in animal facilities.MethodsThis study investigated the automated watering system installed in South and North Barriers of Tsinghua University Laboratory Animal Resources Center (Phase II). Water leakage monitoring was conducted over two periods, one over a period of 3 years and the other over 1.5 years. The occurrence of water leakage events at the two barriers during the monitoring period was statistically analyzed, classifying the causes into four categories: mishandling by personnel, animal behavior, obstruction by foreign objects, and deformation of fittings. The total daily leakage rate due to these causes and the daily leakage rate caused by quality issues, i.e. obstruction by foreign objects and deformation of fittings were calculated. Further analysis and discussion focused on the causes of water leakage and its impact on the facilities. At the same time, the number of caretakers at the end of the monitoring period in the Phase I facility without automated watering system and the Phase II facility with automated watering system were counted. Finally the difference in the number of cages per capita under the two watering systems was calculated.ResultsA total of 52 water leakage incidents occurred in both areas during the monitoring period, with a total daily leakage rate of 0.000 13%. Among them, 31 were caused by personnel mishandling, accounting for approximately 60% of total leakages. Enhanced training, supervision, inspection, and effective reminder measures could reduce leakage caused by personnel mishandling. There were 2 cases of water leakages caused by animal behavior, 0 leakage due to obstruction by foreign objects, and 19 leakages due to system quality issues, with a daily leakage rate of 0.000 07%. According to the operation data of Tsinghua University Laboratory Animal Resources Center, the average number of cages managed per person in facilities equipped with the automated watering system was 908, compared to 570 cages in facilities without the automated watering system. This represents an approximate 59% increase in the number of cages managed per person with the adoption of the automated watering system.Conclusion The daily leakage rate of the automated watering system in the Tsinghua University Laboratory Animal Resources Center is significantly lower than the theoretical design rate of 0.003%, which demonstrates the system's safety and effectiveness. Additionally, the adoption of an automated watering system can significantly enhance caretaking efficiency. While initial investments in the system are required, the subsequent increase in efficiency leads to a continuous decrease in labor costs, thereby reducing the total operational expenses of the facility. In the context of modernizing animal facility construction, automated watering systems are becoming an essential consideration in facility design and operation.

With the rapid development of the biopharmaceutical industry in China, the laboratory animal sector has entered a stage of rapid growth, and the construction of facility operation systems has become increasingly automated and intelligent. Compared to traditional laboratory animal facilities, new facilities require a more specialized technical team for the maintenance of air supply and exhaust systems, air conditioning, automated control, and the entire barrier system. The Lingang Laboratory’s animal facilities accommodate both large and small animals for feeding and experimental purposes. The facility management team has summarized daily maintenance experiences and explored various operational and maintenance modes based on the characteristics of laboratory operation. After analyzing the advantages and disadvantages of three common modes, this paper provides new ideas for the management of these laboratory animal facilities, and offers guidance for peers in choosing the most appropriate professional maintenance mode.

ObjectiveTo compare the effectiveness and safety of one-lung ventilation and small tidal volume two-lung ventilation anesthesia methods in the training of minimally invasive thoracic surgery on experimental pigs.MethodsForty experimental pigs undergoing robotic thoracic surgery were randomly divided into two groups: two-lung ventilation group (n=20) and one-lung ventilation group (n=20). The two-lung ventilation group underwent single-lumen tracheal intubation, utilizing a small tidal volume with a fast respiratory rate combined with carbon dioxide pneumothorax for anesthesia ventilation during the operation. The one-lung ventilation group received one-lung ventilation using a double-lumen bronchial catheter placed under fiberoptic bronchoscopic guidance. The anesthesia implementation indexes from the two groups were compared, including the values of vital signs such as operative heart rate (HR), noninvasive mean blood pressure (MAP), end-tidal carbon dioxide (ETCO₂), and oxygen saturation (SpO₂), as well as the assessment of surgical training performance.Results The intubation success rate for animals in both groups was 100%, with no intraoperative deaths. The intubation completion time was significantly shorter in the two-lung ventilation group compared to the one-lung ventilation group (P < 0.001). Within each group, SpO₂ levels were significantly higher in the two-lung ventilation group at 30 minutes after the start of thoracic surgery (T₁) and at surgery completion (T₃) compared to 60 minutes after the start of surgery (T₂) (P<0.05). ETCO₂, HR, and MAP were significantly higher at T₂ and T₃ compared to T₁ (P<0.05). In the one-lung ventilation group, SpO₂ levels were significantly higher at T₁ and T₃ compared to T₂ (P<0.05), while ETCO₂ levels gradually increasing over time (P<0.05). In the between-group comparisons at the same time points, SpO₂ levels of the two-lung ventilation group were significantly higher than those of the one-lung ventilation group at all time points (T₁, T₂, T₃) (P<0.05).Conclusion Both one-lung ventilation and two-lung ventilation anesthesia methods are effective and safe for use in surgical training, with controllable effects on intraoperative animal vital signs and minimal impact on surgical operation training, meeting the needs of robotic thoracic surgery training. One-lung ventilation provides a better experience during pneumonectomy procedures, while small tidal volume two-lung ventilation is easier to implement and does not require additional equipment purchase, making it a feasible supplemental anesthesia option for thoracoscopic surgery on experimental pigs.

Improving the reproducibility of biomedical research results is a major challenge. Transparent and accurate reporting of the research process enables readers to evaluate the reliability of the research results and further explore the experiment by repeating it or building upon its findings. The ARRIVE 2.0 guidelines, released in 2019 by the UK National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs), provide a checklist that is applicable to any in vivo animal research report. These guidelines aim to improve the standardization of experimental design, implementation, and reporting, as well as enhance the reliability, repeatability, and clinical translation of animal experimental results. The use of the ARRIVE 2.0 guidelines not only enriches the details of animal experimental research reports, ensuring that information on animal experimental results is fully evaluated and utilized, but also enables readers to understand the content expressed by the author accurately and clearly, promoting the transparency and completeness of the fundamental research review process. At present, the ARRIVE 2.0 guidelines have been widely adopted by international biomedical journals. This article is based on the best practices following the ARRIVE 2.0 guidelines in international journals, and it interprets, explains, and elaborates in Chinese the fifth part of the comprehensive version of the ARRIVE 2.0 guidelines published in PLoS Biology in 2020 (the original text can be found at https://arriveguidelines.org). This section includes the items 6-11 of Recommended 11 section, covering "Animal Care and Monitoring", "Interpretation/Scientific Implications", "Generalisability/Translation", "Protocol Registration", "Data Access" and "Declaration of Interests". Its aim is to promote a comprehensive understanding and use of the ARRIVE 2.0 guidelines among domestic researchers, to enhance the standardization of experimental animal research and reporting, and to promote high-quality development of experimental animal sciences and comparative medicine research in China.

ObjectiveXenotransplantation is an effective way to address the shortage of human organ donors, but it faces serious immune rejection reactions, including hyperacute rejection caused by blood type differences. Establishing a stable, convenient, and reliable method for pig blood type identification can quickly screen suitable donor pigs for xenograft research.MethodsBanna miniature inbred pigs, Diannan small eared pigs, and Bama Xiang pigs were selected as the research objects. DNA was extracted from the blood, oral buccal mucosa, and fetal fibroblasts of the three strains of pigs using DNA extraction kits. The target fragment of the ABO homologous gene EAA intron 7 in pigs was amplified using PCR method. Blood agglutination reaction was used to detect hemolysis in pig anterior vena cava whole blood after adding anti A and B antibodies. Immunohistochemical method was used to detect the expression level of A antigen in pig heart, liver, spleen, lung, and kidney tissues. Immunofluorescence method was used to detect the expression level of A antigen in pig oral mucosa. By comparing the results of different methods for determining pig blood types, the stability and reliability of the PCR method were verified, and a convenient PCR based pigblood type identification method was established.Results Firstly, the blood PCR results of 69 inbred strains of Banna miniature pigs, 7 Diannan small eared pigs, and 34 Bama Xiang pigs showed 20 AO blood types, 66 AA blood types, and 24 O blood types. The PCR results of fetal fibroblasts from 47 Diannan small eared pigs showed that all 47 fetuses were O blood type. Among them, the oral mucosal PCR results of 8 gene edited cloned pigs were consistent with those of donor fetal fibroblasts, all of which were O blood type. The oral mucosal PCR results of 8 wild-type pigs (2 inbred lines of Banna miniature pigs, 4 Diannan small eared pigs, and 2 Bama Xiang pigs) were consistent with the blood PCR identification results. Then, 11 inbred lines of Banna miniature pigs, 4 Diannan small eared pigs, and 2 Bama Xiang pigs were randomly selected for blood agglutination reaction validation, and the results were consistent with the PCR identification results of both blood samples and oral mucosa samples. Moreover, immuno-histochemical analysis was performed on the heart, liver, lung, kidney, and spleen tissues of one Banna miniature pig inbred line and two Bama Xiang pigs, and the results were consistent with blood PCR identification and blood agglutination reaction results. Finally, oral mucosal samples were collected from 2 inbred strains of Banna miniature pigs and 1 Bama Xiang pig for immunofluorescence detection, and the results were consistent with the blood PCR identification results.ConclusionBy collecting fetal cells and oral mucosal samples from live pigs for PCR detection, the blood type of pigs can be accurately and efficiently identified, providing a convenient method for blood type screening of xenograft donor pigs.