马/驴源马链球菌马亚种新疆分离株小鼠感染模型的建立及验证

doi:10.16431/j.cnki.1671-7236.2025.03.035

摘要/Abstract

摘要： 【目的】探索采用马/驴源马链球菌马亚种诱导小鼠感染模型的条件及方法,为马腺疫新药研发及其他相关研究奠定试验基础。【方法】选择昆明小鼠100只，将马源马链球菌马亚种新疆株(SEE-M)和驴源马链球菌马亚种新疆株(LXY019)分别设置相应梯度浓度感染小鼠，测定菌株感染小鼠的最低完全致死量(minimum complete lethal dose，MLD)。将30只昆明小鼠随机分为3组(模型Ⅰ组：SEE-M株感染；模型Ⅱ组：LXY019株感染；空白对照组：生理盐水)，每组10只，分别以80% MLD浓度的相应菌株感染小鼠建立马腺疫感染模型，观察小鼠死亡情况。通过对小鼠脏器系数、内脏载菌量、血清炎性因子及组织病理学等进行检测，验证小鼠感染模型的构建情况。【结果】马源和驴源马链球菌马亚种感染小鼠的MLD分别为1.875×10⁹和8.750×10⁸ CFU。以80% MLD的马源和驴源马链球菌马亚种感染小鼠建立马腺疫动物模型，死亡率分别为60%和70%，体重呈下降趋势。小鼠感染模型验证结果表明，与对照组相比，模型Ⅰ、Ⅱ组小鼠肝脏、肺脏、肾脏指数显著升高(P＜0.05)；模型Ⅰ、Ⅱ组小鼠各脏器组织均表现为马链球菌马亚种感染阳性，其中肝脏、脾脏、肺脏和肾脏的载菌量显著高于心脏和脑(P＜0.05)；模型Ⅰ、Ⅱ组小鼠血清中肿瘤坏死因子α(tumor necrosis factor alpha，TNF-α)和白细胞介素-6(interleukin-6，IL-6)含量极显著高于对照组(P＜0.01)。病理切片观察结果显示，模型Ⅰ、Ⅱ组小鼠内脏均有明显的炎性细胞浸润、出血、结构被破坏、内脏细胞坏死脱落等病理变化。【结论】以1.5×10⁹ CFU马源马链球马亚种和7×10⁸ CFU驴源马链球菌马亚种感染小鼠可成功建立马腺疫动物模型，小鼠感染模型各内脏均会被侵染，其中对肺脏、肝脏、脾脏、肾脏的影响最为显著，本研究结果为马腺疫的防治及靶向药物研发奠定试验基础。

关键词: 马链球菌马亚种; 马腺疫; 动物模型; 细胞因子

Abstract: 【Objective】 This study was aimed to explore the conditions and methods of the infection mice model induced by Streptococcus equi subsp. equi from horse/donkey,and lay a foundation for the development of new drug of horse/donkey strangle and related research.【Method】 100 Kunming mice were selected and infected with different concentrations of hourse source Streptococcus equi Xinjiang strain (SEE-M) and donkey source Streptococcus equi Xinjiang strain (LXY019),the minimum complete lethal dose (MLD) was determined.Then 30 Kunming mice were randomly divided into 3 groups (Model Ⅰ:SEE-M strain infection;Model Ⅱ:LXY019 strain infection;Control:Normal saline),10 mice in each group.Mice were infected with the corresponding strain of 80% MLD to establish the model of strangle infection,and the death of mice was observed.By detecting the organ coefficient,visceral bacterial load,serum inflammatory factors,and histopathology of mice,the construction of the mouse infection model was verified.【Result】 The results showed that the MLD of mice infected with horse/donkey derived Streptococcus equi subsp.equi was 1.875×10⁹ and 8.750×10⁸ CFU,respectively.The horse/donkey strangle model was established by infecting mice with 80% MLD horse/donkey Streptococcus equi subsp. equi.The mortality rates were 60% and 70% respectively,and the body weight showed a downward trend.The experimental results of mice infection model showed that compared with control group,the liver,lung and kidney organ indexes of mice in model Ⅰ and model Ⅱ groups were significantly increased (P＜0.05).All organs of the mice in model Ⅰ and model Ⅱ groups showed Streptococcus equi subsp.equi infection positive,and the bacterial load in liver,spleen,lung and kidney was significantly higher than that in heart and brain (P＜0.05).The levels of tumor necrosis factor alpha (TNF-α) and interleukin-6 (IL-6) in serum of mice in model Ⅰ and model Ⅱ groups were extremely significantly increased (P＜0.01).Pathological section results showed that the organs of mice in model Ⅰ and model Ⅱ groups showed obvious pathological changes such as inflammatory cell infiltration,bleeding,structural destruction,and necrosis and shedding of visceral cells.【Conclusion】 Infection of mice with 1.5×10⁹ CFU of Streptococcus equi subsp.equi from horses and 7×10⁸ CFU of Streptococcus equi subsp.equi from donkeys could successfully establish equine strangle animal model. All the organs of infected mice were infected by pathogenic bacteria,especially lungs,livers,spleens and kidneys.The results laid a foundation for the prevention and treatment of equine strangle and the development of targeted drugs.

Key words: Streptococcus equi subsp.equi; equine strangle; animal model; cytokine

中图分类号:

S852.61

刘丹丹, 李金荣, 高函雅, 李姝怡, 彭菲, 徐李依娜, 王馨, 郝宝山, 买占海, 阿得力江·吾斯曼, 赛福丁·阿不拉, 刘建华, 张伟. 马/驴源马链球菌马亚种新疆分离株小鼠感染模型的建立及验证[J]. 中国畜牧兽医, 2025, 52(3): 1342-1351.

LIU Dandan, LI Jinrong, GAO Hanya, LI Shuyi, PENG Fei, XU Liyina, WANG Xin, HAO Baoshan, MAI Zhanhai, WUSIMAN Adelijiang, ABULA Saifuding, LIU Jianhua, ZHANG Wei. Establishment and Verification of Mice Infection Model of Horse/Donkey Source Streptococcus equi subsp.equi in Xinjiang[J]. China Animal Husbandry and Veterinary Medicine, 2025, 52(3): 1342-1351.

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