中文摘要：

为了在探究单一添加不同浓度的赖氨酸对原代奶牛乳腺上皮细胞的增殖,以及mTOR信号通路介导的酪蛋白合成相关基因的影响.试验用厄尔平衡溶液（EBSS）代替正常培养基来处理原代奶牛乳腺上皮细胞,在此基础上依次添加不同浓度的赖氨酸,采用MTT法检测细胞12h和24h的增殖和利用qRT-PCR技术检测4个编码酪蛋白基因和8个mTOR信号通路中与乳蛋白合成翻译相关基因的相对表达量.结果表明：添加赖氨酸12h,浓度为0.5～24mmol/L时,原代奶牛乳腺上皮细胞增殖数量增加（P=0.05）;添加赖氨酸24h,浓度为0.5～8mmol/L时,细胞增殖数量增加（P〈0.01）.当赖氨酸的添加浓度为0.5～16 mmol/L时,CSN1S1、CSN1S2、CSN2和CSN3基因表达均显著上调（P〈0.01）.当赖氨酸添加量为0.5～16mmol/L时,mTOR和raptor基因的表达量显著上调（P〈0.05）.在添加不同浓度的赖氨酸时,下游通路信号因子S6K1、4EBP1和eEF2基因表达均显著上调（P〈0.01）;rps6基因表达上调,eIF4E基因表达下调,但差异均不显著.以上结果表明,补充赖氨酸能显著促进乳腺上皮细胞中酪蛋白的合成,这一过程与mTOR信号通路介导蛋白质合成相关.

英文摘要：

The objective of this study was to use the primary bovine mammary epithelial cells as the model,understanding the regulatory effects of single supplement with different concentrations of lysine oncells proliferation by MTT and milk protein synthesis molecular mechanism by qRT-PCR.Treatment groups based on the Earle＇s balanced salts were added with lysine of different concentrations.The primary bovine mammary epithelial cell proliferation in 12 hand 24hand the gene on milk protein synthesis were detected.The results showed that adding 0.5～24mmol/L lysine for 12 himproved the proliferation of primary bovine mammary epithelial cell（P=0.05）;adding 0.5～8mmol/L lysine for 24 h,the rate of primary bovine mammary epithelial cell proliferation significantly increased（P〈0.01）.The expression of genes CSN1S1,CSN1S2,CSN2 and CSN3 significantly increased（P〈0.01）when the concentration of lysine was 0.5～8mmol.At the concentration of lysine was 0.5～16mM,the expression of genes mTOR and raptor related to mTORC1 both increased（P〈0.05）.The expression of genes S6K1,4EBP1,eEF2 related to mTOR signaling pathway increased（P〈0.01）,but the increasing of rps6 was not significantly（P〈0.05）.Expression of gene eIF4 E decreased,but not significant（P〈0.05）.These results demonstrated that lysine supplements could significantly promote the synthesis of casein,which the process might be a potential control point in the regulation of milk protein synthesis in the primary mammary epithelial cell.