1.Effect of Processed Polygonatum cyrtonema in Preventing Depression Induced by Chronic Unpredictable Mild Stress in Female Rats
Xinyu DENG ; Chunhua MA ; Zimeng WANG ; Man TANG ; Xinran LI ; Lurong YU ; Xianyuan HE
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(7):117-124
ObjectiveTo observe the prevention and control effect of processed Polygonatum cyrtonema on depression induced by chronic unpredictable mild stress (CUMS) in female rats. MethodsForty rats were assigned into control, model, and low-, medium-, and high-dose processed P. cyrtonema groups according to the random number table method, with 8 rats in each group. The rat model of depression was established with the CUMS method. The body mass, open field test, forced swimming test, Morris water maze test, levels of neurotransmitters [dopamine (DA), 5-hydroxytryptamine (5-TH), and acetylcholine (ACh)], serum levels of sex hormones [gonadotropin-releasing hormone(GnRH), testosterone (T), and estradiol (E2)] and inflammatory factors [tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-10], and mRNA and protein levels of factors in the brain-derived neurotrophic factor (BDNF)/tyrosine kinase receptor B (TRKB)/cAMP-response element binding protein (CREB) pathway were employed to evaluate the effect of processed P. cyrtonema on the CUMS-induced depression in female rats. ResultsThe body mass, open field test results, and forced swimming test results showed that the rat model of depression was successfully established. The comparison of behaviors, neurotransmitters, sex hormones, inflammatory factors, and neural pathways among groups showed that processed P. cyrtonema had different effects of preventing the development of depression in female rats. SPSS 25 was used for statistical analysis of error and significance. T test was conducted between groups. Each treatment group showed significant therapeutic effect compared with the model group (P<0.05). Processed P. cyrtonema elevated the level of 5-TH (P<0.01) and lowered the levels of DA and ACh (P<0.01) in the brain tissue of female rats. In addition, it reduced the serum levels of GnRH, T, E2, TNF-α, and IL-6 (P<0.05) and up-regulated the mRNA levels of BDNF and TRKB in the rat brain. ConclusionProcessed P. cyrtonema has a non-hyperactive preventive effect on CUMS-induced depression in rats, which provides a theoretical basis for the development of processed P. cyrtonema as a functional food product.
2.Structure and Function of GPR126/ADGRG6
Ting-Ting WU ; Si-Qi JIA ; Shu-Zhu CAO ; De-Xin ZHU ; Guo-Chao TANG ; Zhi-Hua SUN ; Xing-Mei DENG ; Hui ZHANG
Progress in Biochemistry and Biophysics 2025;52(2):299-309
GPR126, also known as ADGRG6, is one of the most deeply studied aGPCRs. Initially, GPR126 was thought to be a receptor associated with muscle development and was primarily expressed in the muscular and skeletal systems. With the deepening of research, it was found that GPR126 is expressed in multiple mammalian tissues and organs, and is involved in many biological processes such as embryonic development, nervous system development, and extracellular matrix interactions. Compared with other aGPCRs proteins, GPR126 has a longer N-terminal domain, which can bind to ligands one-to-one and one-to-many. Its N-terminus contains five domains, a CUB (complement C1r/C1s, Uegf, Bmp1) domain, a PTX (Pentraxin) domain, a SEA (Sperm protein, Enterokinase, and Agrin) domain, a hormone binding (HormR) domain, and a conserved GAIN domain. The GAIN domain has a self-shearing function, which is essential for the maturation, stability, transport and function of aGPCRs. Different SEA domains constitute different GPR126 isomers, which can regulate the activation and closure of downstream signaling pathways through conformational changes. GPR126 has a typical aGPCRs seven-transmembrane helical structure, which can be coupled to Gs and Gi, causing cAMP to up- or down-regulation, mediating transmembrane signaling and participating in the regulation of cell proliferation, differentiation and migration. GPR126 is activated in a tethered-stalk peptide agonism or orthosteric agonism, which is mainly manifested by self-proteolysis or conformational changes in the GAIN domain, which mediates the rapid activation or closure of downstream pathways by tethered agonists. In addition to the tethered short stem peptide activation mode, GPR126 also has another allosteric agonism or tunable agonism mode, which is specifically expressed as the GAIN domain does not have self-shearing function in the physiological state, NTF and CTF always maintain the binding state, and the NTF binds to the ligand to cause conformational changes of the receptor, which somehow transmits signals to the GAIN domain in a spatial structure. The GAIN domain can cause the 7TM domain to produce an activated or inhibited signal for signal transduction, For example, type IV collagen interacts with the CUB and PTX domains of GPR126 to activate GPR126 downstream signal transduction. GPR126 has homology of 51.6%-86.9% among different species, with 10 conserved regions between different species, which can be traced back to the oldest metazoans as well as unicellular animals.In terms of diseases, GPR126 dysfunction involves the pathological process of bone, myelin, embryo and other related diseases, and is also closely related to the occurrence and development of malignant tumors such as breast cancer and colon cancer. However, the biological function of GPR126 in various diseases and its potential as a therapeutic target still needs further research. This paper focuses on the structure, interspecies differences and conservatism, signal transduction and biological functions of GPR126, which provides ideas and references for future research on GPR126.
3.Effect of Processed Polygonatum cyrtonema in Preventing Depression Induced by Chronic Unpredictable Mild Stress in Female Rats
Xinyu DENG ; Chunhua MA ; Zimeng WANG ; Man TANG ; Xinran LI ; Lurong YU ; Xianyuan HE
Chinese Journal of Experimental Traditional Medical Formulae 2025;31(7):117-124
ObjectiveTo observe the prevention and control effect of processed Polygonatum cyrtonema on depression induced by chronic unpredictable mild stress (CUMS) in female rats. MethodsForty rats were assigned into control, model, and low-, medium-, and high-dose processed P. cyrtonema groups according to the random number table method, with 8 rats in each group. The rat model of depression was established with the CUMS method. The body mass, open field test, forced swimming test, Morris water maze test, levels of neurotransmitters [dopamine (DA), 5-hydroxytryptamine (5-TH), and acetylcholine (ACh)], serum levels of sex hormones [gonadotropin-releasing hormone(GnRH), testosterone (T), and estradiol (E2)] and inflammatory factors [tumor necrosis factor-α (TNF-α), interleukin (IL)-6, and IL-10], and mRNA and protein levels of factors in the brain-derived neurotrophic factor (BDNF)/tyrosine kinase receptor B (TRKB)/cAMP-response element binding protein (CREB) pathway were employed to evaluate the effect of processed P. cyrtonema on the CUMS-induced depression in female rats. ResultsThe body mass, open field test results, and forced swimming test results showed that the rat model of depression was successfully established. The comparison of behaviors, neurotransmitters, sex hormones, inflammatory factors, and neural pathways among groups showed that processed P. cyrtonema had different effects of preventing the development of depression in female rats. SPSS 25 was used for statistical analysis of error and significance. T test was conducted between groups. Each treatment group showed significant therapeutic effect compared with the model group (P<0.05). Processed P. cyrtonema elevated the level of 5-TH (P<0.01) and lowered the levels of DA and ACh (P<0.01) in the brain tissue of female rats. In addition, it reduced the serum levels of GnRH, T, E2, TNF-α, and IL-6 (P<0.05) and up-regulated the mRNA levels of BDNF and TRKB in the rat brain. ConclusionProcessed P. cyrtonema has a non-hyperactive preventive effect on CUMS-induced depression in rats, which provides a theoretical basis for the development of processed P. cyrtonema as a functional food product.
4.Carnosic acid inhibits osteoclast differentiation by inhibiting mitochondrial activity
Haishan LI ; Yuheng WU ; Zixuan LIANG ; Shiyin ZHANG ; Zhen ZHANG ; Bin MAI ; Wei DENG ; Yongxian LI ; Yongchao TANG ; Shuncong ZHANG ; Kai YUAN
Chinese Journal of Tissue Engineering Research 2025;29(2):245-253
BACKGROUND:Carnosic acid,a bioactive compound found in rosemary,has been shown to reduce inflammation and reactive oxygen species(ROS).However,its mechanism of action in osteoclast differentiation remains unclear. OBJECTIVE:To investigate the effects of carnosic acid on osteoclast activation,ROS production,and mitochondrial function. METHODS:Primary bone marrow-derived macrophages from mice were extracted and cultured in vitro.Different concentrations of carnosic acid(0,10,15,20,25 and 30 μmol/L)were tested for their effects on bone marrow-derived macrophage proliferation and toxicity using the cell counting kit-8 cell viability assay to determine a safe concentration.Bone marrow-derived macrophages were cultured in graded concentrations and induced by receptor activator of nuclear factor-κB ligand for osteoclast differentiation for 5-7 days.The effects of carnosic acid on osteoclast differentiation and function were then observed through tartrate-resistant acid phosphatase staining,F-actin staining,H2DCFDA probe and mitochondrial ROS,and Mito-Tracker fluorescence detection.Western blot and RT-PCR assays were subsequently conducted to examine the effects of carnosic acid on the upstream and downstream proteins of the receptor activator of nuclear factor-κB ligand-induced MAPK signaling pathway. RESULTS AND CONCLUSION:Tartrate-resistant acid phosphatase staining and F-actin staining showed that carnosic acid dose-dependently inhibited in vitro osteoclast differentiation and actin ring formation in the cell cytoskeleton,with the highest inhibitory effect observed in the high concentration group(30 μmol/L).Carnosic acid exhibited the most significant inhibitory effect during the early stages(days 1-3)of osteoclast differentiation compared to other intervention periods.Fluorescence imaging using the H2DCFDA probe,mitochondrial ROS,and Mito-Tracker demonstrated that carnosic acid inhibited cellular and mitochondrial ROS production while reducing mitochondrial membrane potential,thereby influencing mitochondrial function.The results of western blot and RT-PCR revealed that carnosic acid could suppress the expression of NFATc1,CTSK,MMP9,and C-fos proteins associated with osteoclast differentiation,and downregulate the expression of NFATc1,Atp6vod2,ACP5,CTSK,and C-fos genes related to osteoclast differentiation.Furthermore,carnosic acid enhanced the expression of antioxidant enzyme proteins and reduced the generation of ROS during the process of osteoclast differentiation.Overall,carnosic acid exerts its inhibitory effects on osteoclast differentiation by inhibiting the phosphorylation modification of the P38/ERK/JNK protein and activating the MAPK signaling pathway in bone marrow-derived macrophages.
5.Proportions of memory T cells and expression of their associated cytokines in lymph nodes of mice infected with Echinococcus multilocularis
Yinshi LI ; Duolikun ADILAI ; Bingqing DENG ; Ainiwaer ABIDAN ; Sheng SUN ; Wenying XIAO ; Conghui GE ; Na TANG ; Jing LI ; Hui WANG ; Tao JIANG ; Chuanshan ZHANG
Chinese Journal of Schistosomiasis Control 2025;37(2):136-143
Objective To investigate the effects of Echinococcus multilocularis infection on levels of memory T (Tm) cells and their subsets in lymph nodes of mice at different stages of infection, so as to provide new insights into immunotherapy for alveolarechinococcosis. MethodsTwenty-four C57BL/6J mice aged 6 to 9 weeks were randomly divided into the infection group and the control group, of 12 mice in each group. Mice in the infection group were administered with 3 000 E. multilocularis protoscoleces via portal venous injection, while animals in the control group were administered with an equal volume of physiological saline. Three mice from each group were sacrificed 4, 12 weeks and 24 weeks post-infection, and lymph nodes were sampled and stained with hematoxylin and eosin (HE) to investigate the histopathological changes of mouse lymph nodes in the infection group. The expression and localization of T lymphocyte surface markers CD3, CD4, and CD8 were observed in mouse lymph nodes using immunohistochemical staining. In addition, lymphocyte suspensions were prepared from mouse lymph nodes in both groups at different time points post-infection, and the levels of Tm cell subsets and their secreted cytokines were detected using flow cytometry. Results HE staining showed diffuse structural alterations in the subcapsular cortical and paracortical regions of mouse lymph nodes in the infection group 4 weeks post-infection with E. multilocularis. Immunohistochemical staining detected CD3, CD4 and CD8 expression in mouse lymph nodes in both groups. Flow cytometry revealed higher proportions of CD4+ Tm cells [(55.3 ± 4.8)% vs. (38.8 ± 6.1)%; t = -4.259, P < 0.05] and CD4+ tissue-resident Tm (Trm) cells [(57.7 ± 3.7)% vs. (34.1 ± 11.2)%; t = -3.990, P < 0.05] in mouse lymph nodes in the infection group than in the control group 4 weeks post-infection, and higher proportions of CD4+ Tm cells [(34.6 ± 3.2)% vs. (23.3 ± 7.5)%; t = -2.764, P < 0.05] and CD4+ Trm cells [(44.0 ± 1.9)% vs. (31.2 ± 1.5)%; t = -4.039, P < 0.05] in mouse lymph nodes in the infection group than in the control group 24 weeks post-infection. The proportions of CD8+ Tm cells were higher in the infection group than in the control group 4 weeks [(56.8 ± 2.7)% vs. (43.9 ± 5.2)%; t = -4.416, P < 0.01] and 12 weeks post-infection [(25.4 ± 2.7)% vs. (12.0 ± 2.6)%; t = -2.552, P < 0.05], while the proportions of tumor necrosis factor (TNF)-α+ CD4+ T cells [(15.7 ± 5.0)% vs. (49.4 ± 6.4)%; t = 7.150, P < 0.01], TNF-α+CD8+ T cells [(20.7 ± 5.5)% vs. (57.5 ± 8.4)%; t = -6.694, P < 0.01], and TNF-α+ CD8+ Tm cells [7.0% (1.0%) vs. 31.0% (11.0%); Z = -2.236, P < 0.05] were lower in the infection group than in the control group 24 weeks post-infection. Conclusions Tm cells levels are consistently increased in lymph nodes of mice at different stages of E. multilocularis infection, with Trm cells as the predominantly elevated subset. The impaired capacity of CD8+ Tm cells to secrete the effector molecule TNF-α in mouse lymph nodes at the late-stage infection may facilitate chronic parasitism of E. multilocularis.
6.Risk assessment of human Spirometra mansoni infections and cross-sectional study on knowledge, attitude and practice towards sparganosis in endemic areas of Henan Province
Yalan ZHANG ; Tiantian JIANG ; Xiaohui MA ; Yan DENG ; Weiqi CHEN ; Yankun ZHU ; Zhenqiang TANG ; Xi-meng LIN ; Hongwei ZHANG
Chinese Journal of Schistosomiasis Control 2025;37(2):190-195
Objective To assess the risk of human Spirometra mansoni infections and investigate the knowledge, attitude and practice (KAP) towards sparganosis mansoni among residents in Henan Province, so as to provide insights into formulation of the sparganosis mansoni control measures. Methods Qinling Village in Fugou County of Zhoukou City, Bali Village in Yancheng District of Luohe City, Duzhai Village in Puyang County of Puyang City and Doushan Village in Luoshan County of Xinyang City were sampled as survey sites in Henan Province from July to August 2023, and more than 40 frogs were sampled from ponds or streams in each survey site for detection of Sparganum mansoni infections. At least 150 residents were sampled using a cluster sampling method from each survey site, and the sero-prevalence of anti-S. mansoni IgG antibody was estimated. In addition, a questionnaire survey was conducted on the KAP towards sparganosis mansoni among participants, and the proportion of eligible KAP, rate of correct KAP and KAP scores were calculated. Results A total 229 frogs were collected from 4 survey sites in 2023, and the overall prevalence of S. mansoni infection was 4.37% (10/229) in frogs, with 7.75% (10/129) prevalence in wild frogs and 0 in farm-bred frogs. A questionnaire survey was performed among 649 residents sampled from 4 survey sites, and 649 serum samples were collected. The seroprevalence of anti-S.mansoni IgG antibody was 0.15% (1/649) and the overall proportion of eligible KAP was 23.73% (154/649) among participants. There were age- (χ2 = 30.905, P = 0.000), educational level- (χ2 = 41.011, P = 0.000), and occupation-specific proportions of eligible KAP among participants (χ2 = 10.721, P = 0.005), and the proportion of eligible KAP decreased with age (χ2 trend = 22.717, P = 0.000) and increased with education levels (χ2 trend = 40.025, P = 0.000). The rates of correct KAP towards sparganosis mansoni were 40.81% (2 119/5 192), 96.66% (1 882/1 947) and 63.81% (3 727/5 841) (χ2 = 1 913.731, P = 0.000) among residents, respectively. The rates of correct KAP towards sparganosis mansoni varied significantly among survey sites (χ2 = 136.872, 42.347 and 255.157; all P values= 0.000, with the highest rate of correct knowledge (51.94%, 748/1 440) and practices (75.86%, 1 229/1 620) in Yancheng District of Luohe City and the highest rate of correct attitudes in Puyang County of Puyang City (99.11%, 446/450) (all P values< 0.05). Conclusions There is still a high transmission risk of sparganosis mansoni in Henan Province, and the KAP towards sparganosis mansoni is required to be improved among residents.
7.Aldehyde Dehydrogenase 2 Gene Mutation May Reduce the Risk of Rupture of Intracranial Aneurysm in Chinese Han Population
Xiheng CHEN ; Siming GUI ; Dachao WEI ; Dingwei DENG ; Yudi TANG ; Jian LV ; Wei YOU ; Jia JIANG ; Jun LIN ; Huijian GE ; Peng LIU ; Yuhua JIANG ; Lixin MA ; Yunci WANG ; Ming LV ; Youxiang LI
Journal of Stroke 2025;27(2):237-249
Background:
and Purpose Ruptured intracranial aneurysms (RIA) are associated with a mortality rate of up to 40% in the Chinese population, highlighting the critical need for targeted treatment interventions for at-risk individuals. Although the impact of aldehyde dehydrogenase 2 (ALDH2) gene mutations on susceptibility to intracranial aneurysms (IA) is well documented, the potential connection between ALDH2 rs671 single-nucleotide polymorphism (SNP) and RIA remains unexplored. Given the increased prevalence of ALDH2 gene mutations among Chinese Han individuals, it is clinically relevant to investigate the link between ALDH2 rs671 SNP and IA rupture.
Methods:
A prospective study was conducted on 546 patients diagnosed with IA to investigate the association between ALDH2 rs671 SNP and the risk of IA rupture.
Results:
The ALDH2 rs671 SNP (ALDH2*2) was significantly more prevalent in patients with unruptured IA (UIA) than in those with RIA (32.56% vs. 18.58%, P=0.004). Multivariate logistic regression analysis revealed that people with the ALDH2 mutation (ALDH2*1/*2 and ALDH2*2/*2 gene type) had a significantly reduced odds ratio (OR=0.49; 95% confidence level [CI] 0.27–0.88; P=0.018) for RIAs. Age-specific subgroup analysis indicated that the ALDH2 mutation provided a stronger protective effect in individuals aged 60 years and above with IA compared to those under 60 years old (OR=0.38 vs. OR=0.52, both P<0.05).
Conclusion
The incidence of RIA was significantly higher in individuals with a normal ALDH2 gene (ALDH2*1/*1) than in those with an ALDH2 rs671 SNP (ALDH2*1/*2 or ALDH2*2/*2). ALDH2 rs671 SNP may serve as a protective factor against RIA in the Chinese Han population.
8.Aldehyde Dehydrogenase 2 Gene Mutation May Reduce the Risk of Rupture of Intracranial Aneurysm in Chinese Han Population
Xiheng CHEN ; Siming GUI ; Dachao WEI ; Dingwei DENG ; Yudi TANG ; Jian LV ; Wei YOU ; Jia JIANG ; Jun LIN ; Huijian GE ; Peng LIU ; Yuhua JIANG ; Lixin MA ; Yunci WANG ; Ming LV ; Youxiang LI
Journal of Stroke 2025;27(2):237-249
Background:
and Purpose Ruptured intracranial aneurysms (RIA) are associated with a mortality rate of up to 40% in the Chinese population, highlighting the critical need for targeted treatment interventions for at-risk individuals. Although the impact of aldehyde dehydrogenase 2 (ALDH2) gene mutations on susceptibility to intracranial aneurysms (IA) is well documented, the potential connection between ALDH2 rs671 single-nucleotide polymorphism (SNP) and RIA remains unexplored. Given the increased prevalence of ALDH2 gene mutations among Chinese Han individuals, it is clinically relevant to investigate the link between ALDH2 rs671 SNP and IA rupture.
Methods:
A prospective study was conducted on 546 patients diagnosed with IA to investigate the association between ALDH2 rs671 SNP and the risk of IA rupture.
Results:
The ALDH2 rs671 SNP (ALDH2*2) was significantly more prevalent in patients with unruptured IA (UIA) than in those with RIA (32.56% vs. 18.58%, P=0.004). Multivariate logistic regression analysis revealed that people with the ALDH2 mutation (ALDH2*1/*2 and ALDH2*2/*2 gene type) had a significantly reduced odds ratio (OR=0.49; 95% confidence level [CI] 0.27–0.88; P=0.018) for RIAs. Age-specific subgroup analysis indicated that the ALDH2 mutation provided a stronger protective effect in individuals aged 60 years and above with IA compared to those under 60 years old (OR=0.38 vs. OR=0.52, both P<0.05).
Conclusion
The incidence of RIA was significantly higher in individuals with a normal ALDH2 gene (ALDH2*1/*1) than in those with an ALDH2 rs671 SNP (ALDH2*1/*2 or ALDH2*2/*2). ALDH2 rs671 SNP may serve as a protective factor against RIA in the Chinese Han population.
9.Aldehyde Dehydrogenase 2 Gene Mutation May Reduce the Risk of Rupture of Intracranial Aneurysm in Chinese Han Population
Xiheng CHEN ; Siming GUI ; Dachao WEI ; Dingwei DENG ; Yudi TANG ; Jian LV ; Wei YOU ; Jia JIANG ; Jun LIN ; Huijian GE ; Peng LIU ; Yuhua JIANG ; Lixin MA ; Yunci WANG ; Ming LV ; Youxiang LI
Journal of Stroke 2025;27(2):237-249
Background:
and Purpose Ruptured intracranial aneurysms (RIA) are associated with a mortality rate of up to 40% in the Chinese population, highlighting the critical need for targeted treatment interventions for at-risk individuals. Although the impact of aldehyde dehydrogenase 2 (ALDH2) gene mutations on susceptibility to intracranial aneurysms (IA) is well documented, the potential connection between ALDH2 rs671 single-nucleotide polymorphism (SNP) and RIA remains unexplored. Given the increased prevalence of ALDH2 gene mutations among Chinese Han individuals, it is clinically relevant to investigate the link between ALDH2 rs671 SNP and IA rupture.
Methods:
A prospective study was conducted on 546 patients diagnosed with IA to investigate the association between ALDH2 rs671 SNP and the risk of IA rupture.
Results:
The ALDH2 rs671 SNP (ALDH2*2) was significantly more prevalent in patients with unruptured IA (UIA) than in those with RIA (32.56% vs. 18.58%, P=0.004). Multivariate logistic regression analysis revealed that people with the ALDH2 mutation (ALDH2*1/*2 and ALDH2*2/*2 gene type) had a significantly reduced odds ratio (OR=0.49; 95% confidence level [CI] 0.27–0.88; P=0.018) for RIAs. Age-specific subgroup analysis indicated that the ALDH2 mutation provided a stronger protective effect in individuals aged 60 years and above with IA compared to those under 60 years old (OR=0.38 vs. OR=0.52, both P<0.05).
Conclusion
The incidence of RIA was significantly higher in individuals with a normal ALDH2 gene (ALDH2*1/*1) than in those with an ALDH2 rs671 SNP (ALDH2*1/*2 or ALDH2*2/*2). ALDH2 rs671 SNP may serve as a protective factor against RIA in the Chinese Han population.
10.Dynamic Monitoring and Analysis of Ammonia Concentration in Laboratory Animal Facilities Under Suspension of Heating Ventilation and Air Conditioning System
Qingzhen JIAO ; Guihua WU ; Wen TANG ; Fan FAN ; Kai FENG ; Chunxiang YANG ; Jian QIAO ; Sufang DENG
Laboratory Animal and Comparative Medicine 2025;45(4):490-495
ObjectiveTo monitor the real-time changes in ammonia concentration in the laboratory animal facility environment before, during, and after the air conditioning system stops supplying air, so as to provide a basis and reference for developing emergency plans for the shutdown of the air conditioning system. MethodsThe laboratory animal facilities of the Wuhan Institute of Biological Products were used as the research object. Ammonia concentration detectors were used to monitor ammonia concentration continuously in the environment of conventional rabbit production facility, SPF hamster production facility, and SPF guinea pig experimental facility before and after the passive shutdown due to repairs and active maintenance shutdown of the air conditioning system, as well as the time for the ammonia concentration to return to daily levels after resuming air supply. ResultsUnder both shutdown modes of the air conditioning system, the trend of ammonia concentration changes in different laboratory animal facilities was consistent, showing a rapid increase after shutdown and a rapid decrease after resuming air supply. Under active maintenance shutdown, the maximum ammonia concentrations in the conventional rabbit production facilities, SPF hamster production facilities, and SPF guinea pig experimental facilities were 9.81 mg/m³, 14.27 mg/m³, and 6.98 mg/m³, respectively. Within 12 minutes after resuming air supply, ammonia concentration could return to normal daily levels. Under passive long-term shutdown, ammonia concentration value was positively correlated with the duration of air supply suspension. As the shutdown duration increased, ammonia concentration continued to increase. The maximum ammonia concentration values in the three facilities occurred at 88 minutes (38.06 mg/m³), 40 minutes (18.43 mg/m³), and 34 minutes (15.61 mg/m³) after air supply suspension, respectively.Within 11 minutes after resuming air supply, ammonia concentration could return to normal daily levels. ConclusionShutdown of the air conditioning system causes a rapid increase in ammonia concentration in laboratory animal facilities, and the rise in ammonia concentration is positively correlated with the duration of air supply suspension. Therefore, when an emergency shutdown of the air-conditioning system is required due to maintenance or other reasons, backup fans should be provided in accordance with the requirements of GB 50447-2008 "Architectural and Technical Code for Laboratory Animal Facilities". Older facilities should make adequate preparations and develop a scientifically sound emergency plan.

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