奶牛金黄色葡萄球菌乳腺炎小鼠模型的建立

Establishment of Mice Models of Staphylococcus aureus of Dairy Cows Mastitis

目的利用从临床乳腺炎奶牛乳样中分离纯化的金黄色葡萄球菌(S.aureus)感染小鼠乳腺,建立奶牛金黄色葡萄球菌乳腺炎小鼠模型。方法将产后8～10 d的ICR远交系母鼠随机分为3组,包括无菌生理盐水对照组,低剂量攻菌组(含金黄色葡萄球菌2×102CFU)和高剂量攻菌组(含金黄色葡萄球菌5×106CFU)。以小鼠第4对乳腺为攻菌部位,用非损伤方法经乳头管注入生理盐水或金黄色葡萄球菌。攻菌24h后采集乳汁进行白细胞计数;从眼球采血,进行血常规检测和流式细胞计数;之后处死母鼠,取乳腺组织进行匀浆细菌计数,并做乳腺组织切片。结果高剂量攻菌组不论是体温、组织学观察,还是乳汁白细胞计数、乳腺匀浆细菌计数、血常规指标和流式细胞计数,都和对照组有显著或极显著差异(P<0.05);而低剂量攻菌组与对照组相比,除血液CD4+/CD8+比值差异显著外(P<0.05),其余指标差异均不显著。结论金黄色葡萄球菌浓度为5×106CFU、攻菌时间24 h时,成功建立了远交系小鼠金黄色葡萄球菌乳腺炎模型,而2×102CFU细菌浓度则不适于远交系小鼠乳腺炎模型的建立。

Objective Infect mouse mammary gland with Staphylococcus aureus （S. aureus） isolated and purified from clinical mastitis milk samples in order to establish a mouse model of Staphylococcus aureus of dairy cows mastitis. Methods 8 -10 days postpartum far inbred ICR female mice were randomly divided into three groups, including the sterile saline control group, low-dose-bacteria-attack group （2 × 102 CFU of Staphylococcus aureus） and high-dose-bacterial-attack group （5× 106CFU of Staphylococcus aureus）. Staphylococcus aureus or sterile saline were injected into the fourth pair mammary gland through the nipple tube with non-invasive method. 24 h after bacteria attack, milk of these rats was collected to do white blood cell count, and blood from eyes to do blood testing and flow cytometry; after the female mice were killed, taking the breast tissue to do homogenate bacterial count, and do biopsy. Results The high-dose group have a significant or very significant difference （P 〈 0.05） with the control group whether in the histological observation and body temperature, or milk white blood cell count, breast homogenate count, some indicators in blood testing and flow cytometry. But compared the low-dose group with the control group, indicators have no significant differences except the blood CD4＋/CD8＋ ratio was significantly different （P 〈 0. 05）. Conclusion The distant strains of mice models of S. aureus mastitis was successfully established when the concentration of Staphylococcus aureus is 5 × 10SCFU, bacterial attack for 24 h, and concentration of 2 x 102 CFU of bacteria is not suitable for the establishment of distant strains of mice models of S. aureus mastitis.