The Study On Dynamic Changes And Function Of TH17/IL-17in Mice Mastitis Induced By Staphylococcus Aurens

The pathogenesis of mastitis induced by Staphylococcus aureus is complex and in-depth understanding of immune response mechanism is the key to the prevention and control of Staphylococcus aureus mastitis. Th17cell subsets and their secretion of the cytokines IL-17play an important role in extracellular bacterial infection and chronic inflammation. Especially the latest study found that DL-17plays an important role in immune protection on skin during Staphylococcus aureus infection, which provides a new target for the prevention and treatment of Staphylococcus aureus skin infections. Mammary gland as special organs, how did the Th17cells/IL-17dynamically change after Staphylococcus aureus infection? What is the function of IL-17in this process? There are few studies have been reported. This study is focused on dynamic changes and function of Th17/IL-17in mice mastitis induced by Staphylococcus aureus. We establised the mice mastitis model induced by Staphylococcus aureus and analysis the dynamic changes of Th17cells and its main effect factor IL-17by flow cytometry and fluorescence quantitative PCR method. Verify the facilitation of cytokines IL-17 secreted by bovine mammary epithelial cells in vitro tests and make a preliminary evaluation for the function of IL-17in mastitis induced by Staphylococcus aureus. This study provided new experimental data to clarify the pathogenesis of staphylococcus aureus mastitis.Results:1. Staphylococcus aureus mastitis infection model in mice was established successfully, and inflammatory cells infiltration in mammary gland tissue have increased along with the time of infection.2. Flow cytometry detection showed that Th1, Th2and Th17cells were significantly increased at3,6,9days after staphylococcus aureus challenge. The relative quantity of IFN-γ、IL-12, IL-4、 IL-10, IL17and IL-23were also elevated by Real-time PCR method. ELISA results showed that the peak expression of IL-17/IL-23in the murine mammary gland appeared on the third day after infection. Colonization of staphylococcus aureus in murine mammary gland decrease along with the time of infection, change trend instead with the changes of IL-17.3. Expressed IL-17successfully in bovine mammary epithelial cells. The Real-time PCR results showed that the expression level of pro-inflammatory factors in bovine mammary epithelial cells were increased by pEGFP-N3-bIL-17transfection during S. aureus infection, which suggested that IL-17might promote the inflammatory factor expression of bovine mammary epithelial cells.This research provided insights into the mechanism of staphylococcus aureus mastitis.