| Mastitis is one of the common diseases in dairy farms, mainly caused by microbial infection. In this study, Staphylococcus aureus was administered through the teat canal to establish the clinical mastitis model in Chinese Holstein. we successfully constructed the S.aureus-induced mastitis model, verified by clinical examination, BMT test, SCC test, histopathological inspection. On this basis, the variation of PGLYRP1 and PTX3 proteins and the S.aureus-mductd immunne responses were explored in the S.aureus-induced mastitis breast tissues using histoligy, western blotting, immunne histochemical and other methods. The main contents and results are as follows:1. To establish the S.aureus-induced mastitis model in Chinese Holstein cows, 1×107CFU/mL S.aureus was administered to a teat duct of three healthy cows each during the mid-lactation milk zone respectively. At 6,12,18 and 24 hours after administering S. aureus, observe the mental state, milk production, appetite, color of the milk, body temperature. The results of BMT test, SCC test in milk and pathological examination showed that after administration, the cows’spirits were low, feed intake decreased, body temperature rose, and breast areas of experimental group were red, swollen, with fever and other obvious symptoms of acute inflammation. The color of milk also changed, the milk was thick, the milk production decreased. The somatic cell count arose dramatically. At 24 hours after administration, the breast areas in experimentation showed the typical symptoms of clinical mastitis, demonstrating a successful model of the S.aureus-induced masitits.2. The pathological features of the S.aureus-induced mastitis:HE staining showed that the mammary of S.aurens-induced mastitis had obvious lesions. Partial vision showed that mammary stroma had significant inflammatory edema and hyperplasia phenomenon, with a lot of neutrophils and lymphocytes in it. Acinus caviry was atrophy and deformation, mammary epithelial cells were not closely connected, acinus caviry had a small amount of flocculent milk and a large number of secretion, mainly shedding mammary epithelial cells and neutrophils, macrophages, lymphocytes and other inflammatory cells. Transmission electron microscopy revealed that there were a large number of S. aureus in experimental mammary breast tissue. Bacteria often gathered around the primary and secondary lysosomes lysosomes, mammary gland epithelial cell nucleus, mitochondria, endoplasmic reticulum, lysosomes and cell membrane had obvious pathological phenomenon. Nuclear chromatin was margination with varying degress. Mitochondrial was in edema and dilatation, and endoplasmic reticulum was slight dilated, network pool appeared inclusive thereof. There were a large number of vacuoles appearred in the cytoplasm within vacuoles, lipid droplets and other contents in it.3. Western blotting and immunne histochemistry showed that PGLYRP1 and PTX3 protein was both expressed in normal breast tissue and S.aureus group. The existence of protein expression in breast normal and S.aureus group was significantly different, PGLYRP1 and PTX3 protein in bacterial protein expression after administration increased. PGLYRP1 is a secreted protein, mainly located in the neutrophil membrane and cytoplasm. PTX3 protein is also secreted proteins, mainly located in the the cell membrane or the cytoplasm of macrophages and neutrophils.Conclusion:Dairy cow mastitis model is typical and easy to establish.It can provide better for immunology research of dairy cow mastitis test base.The occurrence of cow mastitis can cause the destruction of the breast tissue structure.PGLYRP1 and PTX3 protein may be key proteins of dairy cow mastitis and can be used as candidate proteins of dairy mastitis resistance study. |
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