氯化两面针碱通过Wnt/mTOR信号通路缓解热应激水牛乳腺上皮细胞β-酪蛋白含量降低OA北大核心CSTPCD

[Objective]This study aimed to explore the effects of nitidine chloride(NitC)on the reduction of β-casein content in buffalo mammary epithelial cells caused by heat stress,in order to provide a theoretical basis for alleviating the negative impact of heat stress on buffalo milk quality in the actual production.[Method]The temperature-humidity index(THI)of the cowshed was recorded in the non-heat stress season and the heat stress season,and the respiratory rate and rectal temperature of the buffalo were detected to determine whether the buffalo was in a state of heat stress;milk samples were collected for milk composition analysis to investigate the effects of heat stress on the β-casein content in buffalo milk;bu-ffalo mammary epithelial cells were used as the research objects,and the buffalo mammary epithelial cells heat stress model was established by treating them at 40.5℃for 24 h.LiCl and LGK974 were used to activate and inhibit the Wnt pathway respectively,and the β-casein content in buffalo mammary epithelial cells and the expression levels of genes and proteins related to β-casein synthesis were detected to explore the mechanism by which nitidine chloride alleviated the decrease of β-casein content in buffalo mammary epithelial cells caused by heat stress.[Result]Compared with the non-heat stress season,the THI in the cowshed increased and exceeded the heat stress threshold of buffaloes in the heat stress season,the respiratory rate and rectal temperature of buffaloes increased significantly(P<0.05,the same below),and the β-casein content in buffalo milk decreased significantly.Cell experiments showed that treatment with 40.5℃for 24 h significantly reduced the β-casein content,cell viability,and the relative expression of Wnt2,mTOR and β-casein genes and proteins in buffalo mammary epithelial cells.Nitidine chloride treatment effectively alleviated the effects of heat stress on buffalo mammary epithelial cells and significantly increased the β-casein content,cell viability and the relative expression of Wnt2,mTOR and β-casein genes and proteins in buffalo mammary epithelial cells.[Conclusion]Heat stress reduces the β-casein content and the relative expression of β-casein synthesis-related genes and proteins in buffalo mammary epithelial cells.Nitidine chloride increases the β-casein content,cell viability and the relative expression of Wnt2,mTOR and β-casein genes and proteins in buffalo mammary epithelial cells through the Wnt/mTOR signaling pathway,alleviating the decrease in β-casein content in buffalo mammary epithelial cells caused by heat stress.