MCT1在犊牛消化道的分布以及SCFA对MCT1表达的影响

Distribution of MCT1 in calf gastrointestinal tract and the effect of SCFA on the expression of MCT1

短链脂肪酸(SCFAs)是由纤维素性饮食在瘤胃内发酵产生的乙酸、丙酸、丁酸以及戊酸等组成的混合物。SCFA对维持反刍动物的能量平衡至关重要,目前对SCFA的吸收机制和影响因素至今尚不清楚,本试验主要研究一元羧酸转运蛋白(monocarboxylate/proton cotransporter isoform 1,MCT1)在犊牛消化道内的分布及SCFA对MCT1表达的影响。运用免疫印迹Western blot和实时荧光定量PCR检测MCT1在犊牛消化道内的分布和表达;在体外试验中,体外添加一定比例的SCFA(乙酸、丙酸和丁酸的混合物)处理犊牛原代瘤胃上皮细胞,检测SCFA对MCT1表达水平的影响。结果显示:MCT1在整个消化道内均有分布,并且在瘤胃内的表达水平显著高于其他部位(P<0.01);体外处理的瘤胃上皮细胞,正常组MCT1的表达水平显著高于(P<0.05)SARA组。结果表明:正常水平的SCFA能够促进MCT1的表达和转运能力,而过量的SCFA抑制MCT1的表达和转运能力。

Short-chain fatty acids （SCFA）, such as acetate, propionate, and butyrate and pentanoate are produced by microbial fermentation of undigested carbohydrate from ingested dietary fiber in the ruminal fluid. SCFA plays an important role in maintaining energy homeostasis. However, the influencing factors and mechanism of SCFA absorption are not fully studied. Here we examined the distribution of MCT1 in calf gastrointestinal tract and the effect of SCFA on the expression of MCT1. In vivo, the distribution of MCT1 in calf gastrointestinal tract was detected by Western blot and qRT-PCR. In vitro ,a mix of SCFA was used to stimulate the ruminal epithelium cells and examine the effect of SCFA on the expression of MCT1. The results showed that MCTI was pres ence in all regions of calf gastrointestinal tract,and the abundance of MCT1 in rumen was signifi- cantly higher than others（P〈0.01）. In vitro ,the expression levels of MCT1 in normal group was higher than in SARA group. In conclusion, the concentration of SCFA in normal group could in- crease the expression of MCT1, however, the concentration of SCFA in SARA group could de- crease the expression of MCT1.