金黄色葡萄球菌对小尾寒羊乳腺组织TLR2表达的影响

Effect of Staphyloccocus aureus on TLR2 Expression in Mammary Glands of Small-tail Han Sheep

Toll样受体能够识别细菌等病原微生物及介导炎症反应信号通路,在先天免疫和获得性免疫中发挥着重要作用。为了解Toll样受体2(TLR2)在小尾寒羊正常乳腺组织及由金黄色葡萄球菌引起的乳腺炎乳腺组织中的表达情况,探讨TLR2在金黄色葡萄球菌乳腺炎致病过程中的作用机制及乳腺上皮细胞在乳腺免疫防御中所起的作用,采用qRT-PCR技术和免疫组织化学染色(IHC)法检测了正常小尾寒羊及金黄色葡萄球菌乳腺炎病理模型小尾寒羊乳腺组织中TLR2基因mRNA及其蛋白的表达情况。结果显示,小尾寒羊正常乳腺组织、金黄色葡萄球菌感染乳腺组织均有TLR2 mRNA及其蛋白表达;但金黄色葡萄球菌感染后乳腺组织中TLR2基因及TLR2蛋白显著高于正常乳腺组织,且感染后48 h TLR2 mRNA和TLR2蛋白相对表达量最高(P<0.05),96 h TLR2 mRNA和蛋白相对表达量较48 h显著降低(P<0.05),正常对照组TLR2的相对表达量最低。通过免疫组织化学染色发现,正常乳腺组织中TLR2蛋白主要定位于乳腺腺泡上皮,而感染金黄色葡萄球菌后乳腺组织中TLR2蛋白主要表达在乳腺腺泡腔中脱落的乳腺上皮细胞和以淋巴细胞为主的炎性细胞上。结果表明,乳腺感染金黄色葡萄球菌后,乳腺上皮细胞是病原菌作用的靶标,通过上调表达TLR2识别病原菌,激发先天免疫。

Toll-like receptor（ TLR） family plays a key role in innate immunity and various inflammatory responses,for recognizing the bacterial pathogen and mediated the signal path of inflammation. To investigate the expressions of TLR2 in mammary glands of Small-tail han sheep were infected with Staphylococcus aureu,and to explore the mechanism of TLR2 in mastitis,the qRT-PCR and IHC technology was used to detect the expression of TLR2 mRNA and TLR2 protein in the mammary gland of control and experimental groups. The results showed that the TLR2 mRNAs and protein were expressed in all mammary glands of Small-tail han sheep in control and experimental groups. The levels of TLR2 mRNA and protein was lowest in control group,was highest at 48 h after Staphylococcus aureu infusion,significantly higher than that of control and 96 h group（ P 0. 05）. After infected 96 h,the levels of TLR2 mRNA and protein was significantly reduced than that of 48 h group（ P 0. 05）. The protein of TLR2 were located in the epithelial cell of mammary gland acinus,were expressed in epithelial cell of mammarygland acinus dropped and inflammatory cells as lymphocytes after effected Staphylococcus aureu. The results implied that the expression of TLR2 in the epithelial cell of mammary gland was up-regulated to recognize pathogenic bacteria,arouse the innate immunity.