The Effects Of Serum Hormones And Nutrients On The Migration Of Neutrophils Across The Mammary Epithelial In Dairy Cows

Poly-morphonuclear Neutrophils（PMN）is one of phagocytic cells,which number accounts for about 25% in the all white blood cells of cattle,and plays an important role in the non-specific immune system of dairy cows.PMN can protect animal health through phagocytosis,respiratory bursts and the formation of extracellular trapping networks（NET）to kill pathogenic bacteria.When the cows have a breast infection,the pathogen will concentrate in the breast acinar cavity.However,the PMN need to cross mammary epithelium into breast acinar cavity to performing a bactericidal function.Therefore,it is academic and practical value of researching the factors of PMN trans-mammary epithelial for preventing and controlling the cows mastitis.In this study,a transwell was build as the test model for researching the function of PMN trans-mammary epithelium in vitro.And the function of hormones,trace elements,SCFA and NEFA,influencing PMN trans-mammary epithelium,were researched by the test model.The test results were as follows:1.E₂ inhibited the number of PMN trans-mammary epithelium in a dose-dependent manner.When the concentration of E₂ was 20 pg/m L,the number of PMN trans-mammary epithelium was decreased significantly（P < 0.01）.The more the concentration of E₂,the more obvious the inhibitory effect;P4 promoted the number of PMN trans-mammary epithelium,and the low concentration（5 ng/m L）and medium concentration（20 ng/m L）were extremely significant（P < 0.01）,and the high concentration of P4（40 ng/m L）was significant（P< 0.05）;PRL and INS had no significant effect on the number of PMN trans-mammary epithelium（P > 0.05）.2.Cu,Zn and Se promoted the number of PMN trans-mammary epithelium in a dose-dependent manner.When the concentration of Cu was 1.5 mg/m L,the number of PMN trans-mammary epithelium was increased significantly（P < 0.05）.The number of PMN trans-mammary epithelium was increased extremely significantly（P < 0.01）,when the concentration of Zn and Se were 5.0 mg/m L and 0.1 mg/m L,respectively.However,the low concentration of Cu and Zn had no significant effect on the number of PMN trans-mammary epithelium（P > 0.05）.3.OA promoted the number of PMN trans-mammary epithelium in a dose-dependent manner.When the concentration of OA was 0.065 mmol/L,the number of PMN trans-mammary epithelium was increased extremely significantly（P < 0.01）.The more the concentration of OA,the more obvious promotive effect;PA and SA had no significant effect on the number of PMN trans-mammary epithelium（P > 0.05）.4.Ac and Bt promoted the number of PMN trans-mammary epithelium in a dose-dependent manner.When the concentration of Ac and Bt were 30 mmol/L and 2.5 mmol/L,respectively,the number of PMN trans-mammary epithelium was increased extremely significantly（P < 0.01）.When the concentration of Bt was 0.5 mmol/L,the number of PMN trans-mammary epithelium was increased significantly（P < 0.05）.However,Pr had no significant effect on the number of PMN trans-mammary epithelium（P > 0.05）.The results showed that the number of PMN trans-mammary epithelium was influenced by hormones,trace elements,SCFA and NEFA.The E₂ inhibited the number of PMN trans-mammary epithelium,and P4,Cu,Zn,Se,OA,Ac,Bt promoted the number of PMN trans-mammary epithelium.