组胺对奶牛瘤胃上皮细胞mTOR自噬通路的影响

Effects of Histamine on mTOR Autophagy Signaling Pathway in Rumen Epithelial Cells of Dairy Cows

奶牛发生亚急性瘤胃酸中毒时短链脂肪酸在瘤胃内大量积累,使瘤胃pH长时间为5. 0～5. 5,瘤胃内菌群紊乱,使组胺酸脱羧产生组胺的细菌增多,因而瘤胃内组胺浓度上升。瘤胃内自噬发生是清除异己,将体内的有害物排出以实现细胞本身的代谢需要和某些细胞器的更新,是机体的重要功能。试验研究了不同时间及浓度组胺对奶牛瘤胃上皮细胞自噬的影响(时间点0,1,3,6,9,18 h;浓度0. 8,1. 6,2. 4 nmol/m L)。结果表明:不同浓度组胺刺激后瘤胃上皮细胞自噬雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)通路中关键蛋白磷酸化mTOR(pmTOR)和自噬降解底物(p62)表达量上升,mTOR、微管相关蛋白1轻链3(LC3)表达量下降。说明组胺高浓度时mTOR自噬通路受到抑制,使清除有害物质功能减弱,从而引起细胞损伤。

When subacute rumen acidosis occurs in dairy cows,short-chain fatty acids accumulate in the rumen,causing rumen pH to be between 5.0 and 5.5 for a long time.The flora in the rumen is disordered,and the bacteria that deaminate histidine to produce histamine are increased,resulting in the increase of the concentration of histamine in the rumen.The autophagy in the rumen is the important function of the body to remove the dissidents and expel the harmful substances in the body to realize the metabolic needs of the cells themselves and the renewal of some organelles.This experiment was to investigate the effects of histamine at different times and concentrations on autophagy in rumen epithelial cells of dairy cows(time points 0,1,3,6,9 and 18 h;concentrations 0.8,1.6 and 2.4 nmol/m L).The results showed that the expression of key protein phosphorylated mTOR(pmTOR)and autophagy degradation substrate(p62)increased in the rumen epithelial cells after stimulation with different concentrations of histamine,mTOR and mTOR.The expression level of microtubule-associated protein 1 light chain 3(LC3)was decreased.The results showed that the mTOR autophagy pathway was inhibited at high concentrations of histamine,which weakened the function of scavenging harmful substances and caused cell damage.