1.Progress and prospect of modern research methods for safety analysis of animal traditional Chinese medicine
YANG Yichun ; ZHU Zeren ; HAN Xu ; ZHANG Yu ; SU Qi
Drug Standards of China 2026;27(1):0021-0027
Exogenous harmful residues and endogenous toxic components are the main contents of safety analysis for animal traditional Chinese medicine. This review summarizes the inspection methods for exogenous harmful residues, as well as the research methods for the toxic effects and mechanisms of endogenous toxic components. The strategies for enhancing efficacy and reducing toxicity of toxic animal drugs and quality control, and prospects the development trend of safety analysis for animal drugs were also discussed. In the detection of exogenous harmful residues in animal drugs, traditional methods such as atomic absorption spectrometry and inductively coupled plasma mass spectrometry are widely used, and new methods such as high-resolution mass spectrometry and biochemical analysis are continuously developing. In the study of endogenous toxic components, the toxic components and mechanisms of some animal drugs including cantharidin and toad venom have been revealed through chemical composition analysis, toxicity tests and multiomics technologies, and some strategies for enhancing efficacy and reducing toxicity have been proposed based on this. In the future, it is necessary to strengthen multidisciplinary integration to innovate detection technologies, clarify toxic mechanisms to achieve efficacy enhancement and toxicity reduction, and improve the biosafety research system, so as to enhance the quality and safety of traditional Chinese medicine animal drugs and promote the internationalization process of traditional Chinese medicine.
2.Phenotypic characteristics of hexavalent chromium compound-induced malignant transformation in NIH/3T3 cells under three-dimensional culture conditions
Qi WANG ; Rui LI ; Wenke YU ; Fangfang ZHANG ; Lijin ZHU
China Occupational Medicine 2026;53(1):24-29
Objective To investigate the malignant phenotypic characteristics of NIH/3T3 cells induced by hexavalent chromium compound under three-dimensional (3D) culture conditions. Methods NIH/3T3 cells in the logarithmic growth phase were divided into four groups: two-dimensional (2D) control group, 2D transformation group, 3D control group, and 3D transformation group. The 2D control group underwent conventional culture, while the 3D control group was cultured with Matrigel. The 2D and 3D transformation groups were exposed to hexavalent chromium compound at a concentration of 0.25 mg/L based on their respective control conditions. Malignant transformation of NIH/3T3 cells was assessed using a soft agar colony formation assay. Malignant phenotypes were evaluated through assays of cell proliferation, apoptosis, cell cycle, wound healing, Transwell migration, and Transwell invasion. Results Cells in both the 2D and 3D transformation groups exhibited anchorage-independent growth, indicating successful malignant transformation. The colony formation rate of cells in the 3D transformation group was higher than that in the 2D transformation group [(6.17±1.31)% vs (1.00±0.41)%, P<0.01]. Compared with the 3D control group, cell proliferation, apoptosis rate, and migration cell count decreased [(100.00±0.00)% vs (95.01±3.49)%, (9.32±0.43)% vs (7.12±0.40)%, (62.50±11.27) vs (48.33±7.31), all P<0.05], while invasion cell count increased [(57.17±9.68) vs (122.83±15.41), P<0.05], and the relative migration area at 12, 24, and 48 hours also increased in 3D transformation group [(4.32±2.09)% vs (10.75±0.45)%, (5.87±1.32)% vs (11.47±0.99)%, (8.74±1.34)% vs (11.79±0.93)%, all P<0.05]. The proportions of cells in G0/G1, S, and G2/M phases between the 3D transformation and 3D control groups had no significant differences (all P>0.05). Conclusion Hexavalent chromium compounds induce key malignant phenotypes in NIH/3T3 cells, including anchorage-independent growth, reduced apoptosis, and enhanced migratory and invasive capacities.
3.Effects of Rehmanniae Radix Praeparata on striatal neuronal apoptosis in ADHD rats via Bcl-2/Bax/caspase-3 pathway.
Jing WANG ; Kang-Lin ZHU ; Xin-Qiang NI ; Wen-Hua CAI ; Yu-Ting YANG ; Jia-Qi ZHANG ; Chong ZHOU ; Mei-Jun SHI
China Journal of Chinese Materia Medica 2025;50(3):750-757
This study investigated the effects of Rehmanniae Radix Praeparata on striatal neuronal apoptosis in rats with attention deficit hyperactivity disorder(ADHD) based on the B-cell lymphoma-2(Bcl-2)/Bcl-2-associated X protein(Bax)/caspase-3 signaling pathway. Twenty-four 3-week-old male spontaneously hypertensive rats(SHR) were randomly divided into a model group, a methylphenidate group(2 mg·kg~(-1)·d~(-1)), and a Rehmanniae Radix Praeparata group(2.4 mg·kg~(-1)·d~(-1)). Age-matched male Wistar Kyoto(WKY) rats were used as the normal control group, with 8 rats in each group. The rats were administered by gavage for 28 days. Body weight and food intake were recorded for each group. The open field test and elevated plus maze test were used to assess hyperactivity and impulsive behaviors. Nissl staining was used to detect changes in striatal neurons and Nissl bodies. Terminal deoxynucleotidyl transferase dUTP nick end labeling(TUNEL) fluorescence staining was used to detect striatal cell apoptosis. Western blot was employed to detect the expression levels of Bcl-2, Bax, and caspase-3 proteins in the striatum. The results showed that compared with the model group, Rehmanniae Radix Praeparata significantly reduced the total movement distance, average movement speed, and central area residence time in the open field test, and significantly reduced the ratio of open arm entries, open arm stay time, and head dipping in the elevated plus maze test. Furthermore, it increased the number of Nissl bodies in striatal neurons, significantly downregulated the apoptosis index, significantly increased Bcl-2 protein expression and the Bcl-2/Bax ratio, and reduced Bax and caspase-3 protein expression. In conclusion, Rehmanniae Radix Praeparata can reduce hyperactivity and impulsive behaviors in ADHD rats. Its mechanism may be related to the regulation of the Bcl-2/Bax/caspase-3 signaling pathway in the striatum, enhancing the anti-apoptotic capacity of striatal neurons.
Animals
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Male
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Apoptosis/drug effects*
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Rats
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Drugs, Chinese Herbal/administration & dosage*
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Caspase 3/genetics*
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Proto-Oncogene Proteins c-bcl-2/genetics*
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bcl-2-Associated X Protein/genetics*
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Rehmannia/chemistry*
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Attention Deficit Disorder with Hyperactivity/physiopathology*
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Signal Transduction/drug effects*
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Neurons/cytology*
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Rats, Inbred SHR
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Rats, Inbred WKY
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Humans
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Corpus Striatum/cytology*
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Plant Extracts
4.Saltwater stir-fried Plantaginis Semen alleviates renal fibrosis by regulating epithelial-mesenchymal transition in renal tubular cells.
Xin-Lei SHEN ; Qing-Ru ZHU ; Wen-Kai YU ; Li ZHOU ; Qi-Yuan SHAN ; Yi-Hang ZHANG ; Yi-Ni BAO ; Gang CAO
China Journal of Chinese Materia Medica 2025;50(5):1195-1208
This study aimed to investigate the effect of saltwater stir-fried Plantaginis Semen(SPS) on renal fibrosis in rats and decipher the underlying mechanism. Thirty-six Sprague-Dawley rats were randomly assigned into control, model, losartan potassium, and low-, medium-, and high-dose(15, 30, and 60 g·kg~(-1), respectively) SPS groups. Rats in other groups except the control group were subjected to unilateral ureteral obstruction(UUO) to induce renal fibrosis, and the modeling and gavage lasted for 14 days. After 14 consecutive days of treatment, the levels of serum creatinine(Scr) and blood urea nitrogen(BUN) in rats of each group were determined by an automatic biochemical analyzer. Hematoxylin-eosin(HE) and Masson staining were used to evaluate pathological changes in the renal tissue. Western blot and immunofluorescence assay were conducted to determine the protein levels of fibronectin(FN), collagen Ⅰ, vimentin, and α-smooth muscle actin(α-SMA) in the renal tissue. The mRNA levels of epithelial-mesenchymal transition(EMT)-associated transcription factors including twist family bHLH transcription factor 1(TWIST1), snail family transcriptional repressor 1(SNAI1), and zinc finger E-box binding homeobox 1(ZEB1), as well as inflammatory cytokines such as interleukin-1β(IL-1β), interleukin-6(IL-6), and tumor necrosis factor-α(TNF-α), were determined by RT-qPCR. Human renal proximal tubular epithelial(HK2) cells exposed to transforming growth factor-β(TGF-β) for the modeling of renal fibrosis were used to investigate the inhibitory effect of SPS on EMT. Network pharmacology and Western blot were employed to explore the molecular mechanism of SPS in alleviating renal fibrosis. The results showed that SPS significantly reduced Scr and BUN levels and alleviated renal injury and collagen deposition in UUO rats. Moreover, SPS notably down-regulated the protein levels of FN, collagen Ⅰ, vimentin, and α-SMA as well as the mRNA levels of SNAI1, ZEB1, TWIST1, IL-1β, IL-6, and TNF-α in the kidneys of UUO rats and TGF-β-treated HK-2 cells. In addition, compared with Plantaginis Semen without stir-frying with saltwater, SPS showed increased content of specific compounds, which were mainly enriched in the mitogen-activated protein kinase(MAPK) signaling pathway. SPS significantly inhibited the phosphorylation of extracellular signal-regulated kinase(ERK) and p38 MAPK in the kidneys of UUO rats and TGF-β-treated HK2 cells. In conclusion, SPS can alleviate renal fibrosis by attenuating EMT through inhibition of the MAPK signaling pathway.
Animals
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Epithelial-Mesenchymal Transition/drug effects*
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Rats, Sprague-Dawley
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Male
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Rats
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Fibrosis/genetics*
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Drugs, Chinese Herbal/administration & dosage*
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Kidney Diseases/pathology*
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Kidney Tubules/pathology*
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Humans
5.Treatment of allergic rhinitis in children by attenuating oxidative stress from sweat pore-Qi-triple energizer system.
China Journal of Chinese Materia Medica 2025;50(5):1419-1426
Sweat pores function is the ascending and descending of Qi. The human body maintains a continuous, holistic, and dynamic balance through the functioning of sweat pores as well as the Qi movement and transformation in the spleen, stomach, and triple energizer. Sweat pores play a crucial role in the generation and development of Zang-fu organs, essence and spirit, and body and orifices, as well as in the onset and progression of diseases. Oxidative stress significantly affects the regulation of inflammation in allergic rhinitis(AR), induces the pathological damage to nasal epithelial cells, and alters immune activity, serving as a key mechanism exacerbating AR symptoms. This mechanism closely aligns with the pathogenesis associated with dysfunction in the sweat pore-Qi-triple energizer system. In recent years, oxidative stress and antioxidants in AR have received increasing attention. Elevated levels of reactive oxygen species, fractional exhaled nitric oxide, and malondialdehyde have become key indicators for the early diagnosis of AR. Classical prescriptions, empirical prescriptions, and newly developed preparations of traditional Chinese medicine(TCM) for external use with anti-inflammatory, anti-allergic, and immune-regulatory effects via antioxidant pathways have demonstrated definite efficacy in treating AR. This provides a basis for understanding the pathogenesis of AR in TCM from a modern medical perspective. Therefore, this paper systematically examines the relationship between the sweat pore-Qi-triple energizer system and AR, incorporating the oxidative stress mechanism into the research on pathogenesis of the disorders. Furthermore, methods for treating AR in children are proposed with TCM preparations for external use which aimed at opening nasal sweat pores, dispersing, searching, channeling with aroma, warming, and dredging, regulating Qi movement in spleen, warming Yang Qi to promote urination, and clearing latent wind to inhibit liver depression.
Humans
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Oxidative Stress/drug effects*
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Rhinitis, Allergic/metabolism*
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Child
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Qi
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Sweat/metabolism*
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Drugs, Chinese Herbal/administration & dosage*
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Medicine, Chinese Traditional
6.Medicinal properties and mechanisms of p-cymene with mild and warm nature based on deficiency-cold and deficiency-heat syndrome models.
Xiao-Fang WU ; Yi LI ; Xing-Yu ZHAO ; Lin-Ze LI ; Qi ZHANG ; Yin-Ming ZHAO ; Ying-Li ZHU ; Chun WANG ; Jian-Jun ZHANG ; Lin-Yuan WANG
China Journal of Chinese Materia Medica 2025;50(8):2032-2040
This paper aims to study the effect of p-cymene on mice with deficiency-cold syndrome induced by hydrocortisone and deficiency-heat syndrome induced by dexamethasone and explore the medicinal properties and mechanism of p-cymene with mild and warm nature based on the dominant characteristics of the two-way applicable conditions of mild drugs. A total of 80 KM mice were randomly divided into blank group, deficiency-cold syndrome model group, deficiency-cold syndrome + ginseng group, and deficiency-cold syndrome + low-dose and high-dose p-cymene groups, as well as blank group, deficiency-heat syndrome model group, deficiency-heat syndrome + American ginseng group, and deficiency-heat syndrome + low-dose and high-dose p-cymene groups. Hydrocortisone and dexamethasone solution were intragastrically administered for 14 consecutive days to prepare deficiency-cold syndrome and deficiency-heat syndrome models. Except for the blank group and the model group intragastrically administered with normal saline, the other groups were intragastrically administrated with drugs for 14 days. The levels of cyclic adenosine monophosphate(cAMP), cyclic guanosine monophosphate(cGMP), triiodothyronine(T3), thyroxine(T4), total cholesterol(TC), triglyceride(TG), immunoglobin G(IgG), and immunoglobin M(IgM) in serum, as well as the activity of Na~+-K~+-ATPase in liver tissue were detected. The expression of transient receptor potential melastatin 8(TRPM8), transient receptor potential vanilloid 1(TRPV1), and uncoupling protein 1(UCP1) in brown adipose tissue of deficiency-cold syndrome model after intervention with p-cymene was studied. The results showed that p-cymene could effectively improve the levels of cAMP, cAMP/cGMP, TC, IgM, and IgG in serum and the activity of Na~+-K~+-ATPase in liver tissue of mice with deficiency-cold syndrome and reduce the content of cGMP. The effects on T3, T4, and TG were not statistically significant. At the same time, p-cymene could reduce the levels of cAMP, cAMP/cGMP, and T4 in serum and the activity of Na~+-K~+-ATPase in liver tissue of mice with deficiency-cold syndrome and increase the levels of cGMP, IgM, and IgG, and it had no effect on T3, TC, and TG. In addition, p-cymene could up-regulate the expression of TRPV1 and UCP1 in brown fat of mice with deficiency-cold syndrome and down-regulate the expression of TRPM8. In summary, p-cymene could significantly regulate the syndrome indexes of mice with deficiency-cold syndrome, and some indexes of mice with deficiency-heat syndrome could be improved, but the effects on lipid metabolism and energy metabolism indexes were not obvious, indicating that the regulation effect of p-cymene on deficiency-cold syndrome model was more prominent and that the medicinal properties of p-cymene were mild and warm. The regulation of TRPV1/TRPM8/UCP1 channel expression may be the molecular biological mechanism of p-cymene with mild and warm nature affecting the energy metabolism of the body.
Animals
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Cymenes
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Mice
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Drugs, Chinese Herbal/administration & dosage*
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Male
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Disease Models, Animal
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Humans
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Cyclic AMP/metabolism*
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Monoterpenes/administration & dosage*
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Liver/metabolism*
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Cyclic GMP/metabolism*
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TRPV Cation Channels/genetics*
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Uncoupling Protein 1/genetics*
7.Correlation between dynamic contrast-enhanced MRI imaging and clinical pathological features of invasive breast cancer and lymphovascular invasion
Shi-Qi GUO ; Yu-Jiao XIE ; Qing-Yang LI ; Si-Yi CHEN ; Jia-Hong SUN ; Zhao-Feng GAO ; Jun-Qing LIANG ; Yu-Hui CHEN ; Bao-Shi BAO ; Li ZHU ; Jian-Dong WANG
Medical Journal of Chinese People's Liberation Army 2025;50(7):847-854
Objective To explore the relationship between dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)and clinical pathological features of invasive breast cancer and lymphovascular invasion(LVI).Methods Imaging and clinical pathological data were retrospectively collected from 508 patients with invasive breast cancer who underwent breast DCE-MRI at the First Medical Center of Chinese PLA General Hospital from January 2019 to August 2021.Patients were divided into the LVI-positive(LVI+)group(n=79)and LVI-negative(LVI-)group(n=429)based on postoperative pathological results.Univariate and multivariate logistic regression analyses were used to identify risk factors for LVI.Results Compared with LVI-group,LVI+group had a higher proportion of patients aged<45 years(44.3%vs.27.0%,P=0.002),non-mass-like enhancement(NME)(31.7%vs.17.7%,P=0.004),Ki-67 expression rate(40.0%vs.30.0%,P<0.001),high Ki-67 expression(94.9%vs.78.1%,P=0.001),Luminal B subtype(76.0%vs.60.1%,P=0.008),and positive axillary lymph nodes rate(72.2%vs.31.5%,P<0.001),while the proportion of Luminal A subtype was lower(2.5%vs.21.5%,P<0.001).Univariate and multivariate logistic regression analyses showed that age≥45 years(OR=0.468,95%CI 0.280-0.783,P=0.004)was an independent protective factor for LVI,while NME(OR=1.987,95%CI 1.126-3.444,P=0.016)was an independent risk factor.Compared with Luminal A subtype,patients with Luminal B subtype(OR=10.482,95%CI 3.164-64.923,P=0.001),HER-2 overexpression subtype(OR=11.571,95%CI 2.755-79.341,P=0.003)and triple-negative subtypes(OR=8.433,95%CI 1.985-57.908,P=0.009)had a higher risk of LVI.Conclusions Age≥45 years is an independent protective factor for LVI,while NME is an independent risk factor.Among molecular subtypes,patients with Luminal B,HER-2 overexpression and triple-negative subtypes have a higher risk of LVI compared with the Luminal A subtype.
8.EFFECT OF PD-1 DEFICIENCY ON IMMUNE RESPONSE IN MICE INFECTED WITH TRICHINELLA SPIRALIS
Si-Meng ZHAO ; Xin-Yang HUANG ; Yi-Qi LIU ; Yao ZHANG ; Yan YU ; Jing-Jing HUANG ; Xin-Ping ZHU ; Yu-Li CHENG
Acta Parasitologica et Medica Entomologica Sinica 2025;32(2):65-72
Objective To investigate the effect of programmed death-1(PD-1)on cell infiltration in muscle tissue and immune response types in mice infected with Trichinella spiralis.Methods C57BL/6J wild-type(WT)and PD-1 deficient(PD-1-/-)mice were infected with T.spiralis(400 muscle larvae per mouse),and samples were collected on day 35 after infection.The proportions of infiltrating inflammatory cells and fibroblasts around encapsulated larvae were assessed by immunohistochemistry.The expression levels of interferon-γ(IFN-γ),interleukin(IL)-4,IL-5,IL-13,and eotaxin in muscle tissue were measured using enzyme-linked immunosorbent assay.Peripheral blood and spleen were collected at different time points after infection.The percentages of CD4+IFN-γ+Th1 and CD4+IL-4+Th2 within CD4+T cells population in peripheral blood and spleen of mice were analyzed using flow cytometry.Results The proportions of eosinophils and fibroblasts among total infiltrating cells around the encapsulated larvae in the muscle of PD-1-/-mice were significantly lower than those in WT mice after T.spiralis infection(P<0.01).The infected PD-1-/-mice exhibited higher proportions of macrophages,T cells and B cells in total infiltrating cells than the infected WT mice(P<0.01).The levels of IL-4,IL-5,IL-13,and eotaxin in the muscle tissue of infected PD-1-/-mice were significantly lower than those in infected WT mice(P<0.05).However,IFN-γ levels were not significantly different between the infected WT and PD-1-/-mice.The proportions of Th2 cells in CD4+T cells from peripheral blood and spleen of infected PD-1-/-mice were significantly lower than those in infected WT mice,whereas the proportion of Th1 cells showed no difference among the infected groups.Conclusions PD-1 deletion results in decreased expression of key chemokines of eosinophils and key cytokines of fibroblast formation,and a corresponding decrease in inflammatory cells in muscle in T.spiralis-infected mice.This effect may be associated with a diminished Th2 immune response caused by PD-1 deletion.
9.Isolation and Identification of Staphylococcus xylosus in Nude Mice with Squamous Skin Scurfs
Zhihao KONG ; Xiaofeng WEI ; Lingzhi YU ; Liping FENG ; Qi ZHU ; Guojun SHI ; Chen WANG
Laboratory Animal and Comparative Medicine 2025;45(3):368-375
Objective To isolate pathogenic bacteria from the skin of a nude mouse exhibiting squamous skin scurfs, and perform bacterial identification, traceability analysis, and pathogenicity studies to provide a new approach for the diagnosis of pathogens in nude mice with squamous skin scurfs. MethodsSkin swab samples were collected from a nude mouse exhibiting squamous skin scurfs for nucleic acid testing, bacterial isolation and culture, biochemical identification, 16S rDNA gene amplification and sequencing, and whole genome sequencing to construct a phylogenetic tree. Fifteen BALB/c nude mice were randomized into a saline-treated control group, a high-concentration group treated with 1.8×10⁸ CFU/mL of the isolated bacterial suspension, and a low-concentration group treated with 1.8×10⁷ CFU/mL of the isolated bacterial suspension. Pathogenicity was assessed by animal infection experiments and observation of histopathological changes in skin tissue using HE staining. Results The nucleic acid test for Corynebacterium bovis was negative, excluding infection by this organism. The pathogen isolated on mannitol salt agar and blood agar, combined with Gram staining, suggested a Gram-positive Staphylococcus species. The isolated strain was identified by 16S rDNA sequencing and a fully automated microbial identification system as Staphylococcus xylosus. Phylogenetic tree analysis based on whole genome sequencing showed that the strain was most closely related to an isolate from leafy vegetables in South Korea (GenBank GCA_00207825.1). In the high-concentration group, squamous skin scurfs appeared on the head, neck, and back of nude mice on the 17th day post-infection, while in the low concentration group, similar symptoms appeared on the 20th day post-infection and gradually spread to other areas. The scaling symptoms were transient, lasting for 7 days in the high-concentration group and 3 days in the low-concentration group, after which the skin returned to normal. The infection rate was 33.33% in both the high- and low-concentration groups. No significant pathological changes were observed in the skin tissues of infected mice compared to the control group, indicating marked individual differences in the pathogenicity of the strain in nude mice. Conclusion A strain of Staphylococcus xylosus was isolated from the skin of a nude mouse exhibiting squamous skin scurfs. The strain is an opportunistic pathogen that causes transient squamous skin scurfs without significant histopathological changes, and there are individual differences in the sensitivity of nude mice to this strain. These findings can provide valuable data for pathogen identification in immunodeficient or gene knockout mice.
10.Isolation and Identification of Staphylococcus xylosus in Nude Mice with Squamous Skin Scurfs
Zhihao KONG ; Xiaofeng WEI ; Lingzhi YU ; Liping FENG ; Qi ZHU ; Guojun SHI ; Chen WANG
Laboratory Animal and Comparative Medicine 2025;45(3):368-375
Objective To isolate pathogenic bacteria from the skin of a nude mouse exhibiting squamous skin scurfs, and perform bacterial identification, traceability analysis, and pathogenicity studies to provide a new approach for the diagnosis of pathogens in nude mice with squamous skin scurfs. MethodsSkin swab samples were collected from a nude mouse exhibiting squamous skin scurfs for nucleic acid testing, bacterial isolation and culture, biochemical identification, 16S rDNA gene amplification and sequencing, and whole genome sequencing to construct a phylogenetic tree. Fifteen BALB/c nude mice were randomized into a saline-treated control group, a high-concentration group treated with 1.8×10⁸ CFU/mL of the isolated bacterial suspension, and a low-concentration group treated with 1.8×10⁷ CFU/mL of the isolated bacterial suspension. Pathogenicity was assessed by animal infection experiments and observation of histopathological changes in skin tissue using HE staining. Results The nucleic acid test for Corynebacterium bovis was negative, excluding infection by this organism. The pathogen isolated on mannitol salt agar and blood agar, combined with Gram staining, suggested a Gram-positive Staphylococcus species. The isolated strain was identified by 16S rDNA sequencing and a fully automated microbial identification system as Staphylococcus xylosus. Phylogenetic tree analysis based on whole genome sequencing showed that the strain was most closely related to an isolate from leafy vegetables in South Korea (GenBank GCA_00207825.1). In the high-concentration group, squamous skin scurfs appeared on the head, neck, and back of nude mice on the 17th day post-infection, while in the low concentration group, similar symptoms appeared on the 20th day post-infection and gradually spread to other areas. The scaling symptoms were transient, lasting for 7 days in the high-concentration group and 3 days in the low-concentration group, after which the skin returned to normal. The infection rate was 33.33% in both the high- and low-concentration groups. No significant pathological changes were observed in the skin tissues of infected mice compared to the control group, indicating marked individual differences in the pathogenicity of the strain in nude mice. Conclusion A strain of Staphylococcus xylosus was isolated from the skin of a nude mouse exhibiting squamous skin scurfs. The strain is an opportunistic pathogen that causes transient squamous skin scurfs without significant histopathological changes, and there are individual differences in the sensitivity of nude mice to this strain. These findings can provide valuable data for pathogen identification in immunodeficient or gene knockout mice.

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