Objective To accumulate operating experience and background data for housing mice in individually ventilated cages (IVC).Methods 5 weeks old Balb /c male mice(n =80) were allocated to 8 groups(n =10), which then housed in 5 or 10 per cage in 3 IVC systems(30,50 and 70 air changes /h, respectively) and one open-top cages (OTC) shelf for 8 weeks.Body weight was assessed at the initial date and every week .By the end of the experiment, necropsy was done and organs were separated and weighed .Excelland SPSS software statistics was made to draw the growth curve, and comparative analysis of body weight and organ coefficients was performed between the groups .Results 1.The growth curves of 5-mice per cage were better than that of 10-mice per cage.2.In the IVC groups, the curves trend and fluency of 50 air changes /h were more similar to that of 5-mice housed OTC group.3.The previously mentioned differences were statistically not significant (P >0.05).4.In the liver coefficients, there was a statistically significant difference between the 10-mice housed OTC group and 5-mice housed IVC group with 30 air changes /h(P <0.05), there wasn`t any other significant statistically difference with the organ coefficients between groups (P >0.05).Conclusions Based on the results of this study, the air change frequency on 50 times per hour and keeping 5 Balb/c mice per cage is recommended as the best condition for mouse housing in IVC .

The animal laboratory of pharmaceutical and biological product inspection and testing institutions undertakes important basic support tasks for testing and scientific research work.This article summarizes the management experience accumulated in the operation of our institution's CNAS-CL06 quality management system,providing reference for similar institutions in operation to ensure the scientific nature of animal experimental data.In order to ensure the scientific nature of animal experimental data,the experimental animal institution has successfully passed the CNAS accreditation of the experimental animal institution,and has completed rectification on time during on-site supervision and evaluation.At the same time,regular self inspections of the system have been carried out in accordance with the"Quality and Capability Accreditation Guidelines for Experimental Animal Breeding and Use Institutions"(CNAS-CL06).During the self inspection process,we examined issues while improving the content of the system.Starting from animal procurement,occupational health and safety,animal disease treatment and care,and facility operation emergency drills,we enriched the content of the quality management system,ensured the continuous and effective operation of the system,and ensured the effectiveness and standardization of animal experiment data.At the same time,we contributed to the management ideas of our institution in sharing animal experiment platforms,provide hardware and software support for the construction of cloud platforms for animal experiments.This article aims to explore and form a quality management model for the experimental animal industry based on practical work,being focused in the standardization strategy,continue to deepen the reform of standardization work,and give full play to the basic and strategic role of standardization in the modernization of the animal experiments system.

Objective To study the relationships between differences in tumorigenicity and immu-nogenetic backgrounds of nude mice. Methods According to the Chinese Pharmacopoeia, positive and neg-ative groups were set up in both Laboratory A and B with ten nude mice in each group. Organ tissues were collected for clinicopathological analysis. Blood samples were collected and detected using flow cytometry. DNA was extracted and analyzed with 23 STR markers. Results The positive group of Laboratory B was in-valid (7/10 tumor formation). The two laboratories showed no significant difference in the results of patho-logical analysis, but had significant differences in CD25, CD8, CD4, Th1 and Th2. There were 13 and 18 polymorphic sites respectively found in nude mice of Laboratory A and B. Further analysis of the non-tumor-bearing nude mice in Laboratory B positive group revealed that CD25, Th2, D3Mit29 and D5Mit48 were the specific indexes. Conclusion Differences in tumorigenicity might be related to the diversity of immunoge-netic backgrounds of nude mice.

CRISPR/Cas9 technology has driven the development of various fields in life science.With continuous deepening of its understanding,researchers have made multiple improvements and optimizations to adapt to various application scenarios.The optimization of CRISPR/Cas9 technology has also provided breakthroughs in the establishment of genetically modified mouse models.This article briefly reviews the development process of CRISPR/Cas9 technology and summarizes optimization strategies of CRISPR/Cas9,establishment of conditional knockout/knockin gene-modified mouse models,and delivery systems for CRISPR/Cas9 elements and HDR templates.

Science and technological advancements drive human progress, with laboratory animals serving as essential resources for developments in life sciences and medicine. However, the waste generated by these animals presents new challenges for urban management. Issues such as classification, recycling, effective utilization, and biohazard elimination must be addressed, necessitating the development of regulations, standards, and norms to keep pace with advancements. The construction of quality management system is the foundation and framework for the management of inspection and testing organizations. It should have strong operability and inspectability, enabling continuous improvement of the management level and enhancing the stability of basic management. However, current quality management systems often lack clarity in managing laboratory animal waste, including undefined disposal processes for non-medical institutions, inaccurate waste classification, and inadequate disposal methods for different waste categories. This paper addresses these challenges by identifying necessary processes to be added or removed in the quality management system of National Institutes for Food and Drug Control, developing effective SOPs, proposing practical measures to strengthen supervision and management, and integrating 6S management principles into our quality management system. In conclusion, effective management of laboratory animal waste should be centered on improving the quality management system, emphasizing waste classification and management at the source, controlling biological hazards, minimizing environmental pollution and promoting conditions for sustainable development.

Objective To overcome the limitations of existing human respiratory syncytial virus(hRSV)animal models,such as semi-permissiveness and short duration of infection,this study established an IL2rg gene knockout(IL2rg-/-)rat model using TALEN gene editing technology.Methods The animal model was infected with hRSV intranasally.Clinical characteristics,body weight,and temperature changes were observed over the infection period(0～35 days).The total viral loads in respiratory organs,such as the nasal tissue,trachea,and lungs,were measured at various time points(4,11,20,and 35 days post-infection).Pathological analysis was conducted on target organs at the endpoint of observation(35 days post-infection).Changes in peripheral blood T,B,NK,and NKT cells and various cytokines were assessed at various time points(4,20,and 35 days post-infection).Results(1)IL2rg/-knockout rats sustained high viral loads in the nasal cavity upon intranasal inoculation with hRSV.The average peak titer rapidly reached 1 × 1010 copies/g in nasal tissue and 1 × 107 copies/g up to 5 weeks post-infection.(2)However,no significant pathological changes were noted in nasal,tracheal,or lung tissues.(3)An increase was observed in the content of peripheral blood B cells in hRSV-infected IL2rg--rats.(4)IL-6 and MCP-1 were increased in the early stage of infection and then decreased at the end of the observation period.Conclusions This study established a new IL2rg-/-rat model using TALEN technology and found that this model effectively supported high-level replication and long-term infection of hRSV,providing a good basis for antiviral drug screening and in vivo efficacy evaluation of anti-hRSV antibodies.