亚急性瘤胃酸中毒对奶山羊瘤胃上皮细胞挥发性脂肪酸吸收代谢相关基因表达的影响

Effects of Subacute Ruminal Acidosis on Expression of Volatile Fatty Acid Absorption and Metabolism Related Genes in Ruminal Epithelium of Dairy Goats

本研究旨在探究亚急性瘤胃酸中毒(SARA)对奶山羊瘤胃上皮细胞挥发性脂肪酸(VFA)吸收代谢相关基因mRNA相对表达量和蛋白相对表达量的影响。选取体重[(62.13±4.76)kg]相近的12只经产泌乳期萨能奶山羊,安装永久性瘤胃瘘管,随机分为2组,每组6只羊。对照组饲喂基础饲粮,饲粮非纤维性碳水化合物/中性洗涤纤维(NFC/NDF)为1.15;SARA组通过饲喂NFC/NDF分别为1.15、1.49、2.12、2.66的试验饲粮诱导建立SARA模型。试验期为60 d。试验期结束屠宰采集奶山羊的瘤胃腹囊上皮组织,分别采用实时荧光定量PCR(RT-PCR)、Western blotting法检测瘤胃上皮细胞VFA吸收代谢相关基因的mRNA相对表达量和蛋白相对表达量,并分析瘤胃发酵参数、瘤胃上皮细胞VFA吸收率与VFA吸收代谢相关基因mRNA相对表达量之间的相关性。结果表明:1)与对照组相比,SARA组瘤胃上皮细胞Na^(+)/H^(+)交换蛋白1(NHE1)、酰基辅酶A短链合成酶2(ACSS2)、3-羟基-3-甲基戊二酰辅酶A合成酶1(HMGCS1)、3-羟基-3-甲基戊二酰辅酶A合成酶2(HMGCS2)、3-羟基-3-甲基戊二酰辅酶A还原酶(HMGCR)的mRNA相对表达量极显著上调(P<0.01),Na^(+)/H^(+)交换蛋白3(NHE3)、单羧酸转运蛋白1(MCT1)、下调式腺瘤载体(DRA)的mRNA相对表达量显著上调(P<0.05)。2)与对照组相比,SARA组瘤胃上皮细胞NHE1、NHE3、Na^(+)/H^(+)交换蛋白4(NHE4)、单羧酸转运蛋白2(MCT2)、阴离子交换蛋白2(AE2)、钠/钾ATP酶(Na^(+)/K^(+)-ATPase)、ACSS2、酰基辅酶A短链合成酶3(ACSS3)、3-羟基-3-甲基戊二酰辅酶A裂解酶(HMGCL)、乙酰辅酶A乙酰转移酶1(ACAT1)的蛋白相对表达量显著上调(P<0.05)。综上所述,SARA可以提高瘤胃上皮细胞NHE1、NHE3、MCT1、DRA、ACSS2、HMGCS1、HMGCS2、HMGCR的mRNA相对表达量以及NHE1、NHE3、NHE4、MCT2、AE2、Na^(+)/K^(+)-ATPase、ACSS2、ACSS3、HMGCL和ACAT1的蛋白相对表达量,进而加快瘤胃上皮细胞对VFA的吸收与代谢,缓解SARA对机体的损伤。

The aim of this experiment was to investigate the effects of subacute rumen acidosis(SARA)on the mRNA relative expression levels and protein relative expression levels of volatile fatty acid(VFA)absorption and metabolism related genes in ruminal epithelium of dairy goats.Twelve lactating Saanen dairy goats with similar body weight[(62.13±4.76)kg]were installed permanent rumen fistulas and randomly divided into two groups with 6 goats per group.Goats in the control group were fed a basal diet,and dietary non-fibrous carbohydrate/neutral detergent fiber(NFC/NDF)was 1.15;the others in SARA group was fed experimental diets to establish SARA model,and dietary NFC/NDF were 1.15,1.49,2.12 and 2.66,respectively.The trial period was 60 days.At the end of the experiment,dairy goats were slaughtered and collected the rumen epithelial tissues from ventral sac.The mRNA relative expression levels and protein relative expression levels of VFA absorption and metabolism related genes in ruminal epithelium were detected by real-time PCR(RT-PCR)and Western blotting methods.The correlation between rumen fermentation parameters,VFA absorption rate of ruminal epithelium and mRNA relative expression levels of VFA absorption and metabolism related genes was analyzed.The results showed as follows:1)compared with the control group,the mRNA relative expression levels of Na^(+)/H^(+)exchanger 1(NHE1),acyl-CoA short chain synthetase 2(ACSS2),3-hydroxy-3-methylglutaryl-CoA synthetase 1(HMGCS1),3-hydroxy-3-methylglutaryl-CoA synthetase 2(HMGCS2)and 3-hydroxy-3-methylglutaryl-CoA reductase(HMGCR)in ruminal epithelium of SARA group were significantly up-regulated(P<0.01),and the mRNA relative expression levels of Na^(+)/H^(+)exchanger 3(NHE3),monocarboxylate transporter 1(MCT1)and down-regulated adenoma carrier(DRA)were significantly up-regulated(P<0.05).2)Compared with the control group,the relative protein expression levels of NHE1,NHE3,Na^(+)/H^(+)exchanger 4(NHE4),monocarboxylate transporter 2(MCT2),anion exchanger 2(AE2),Na^(+)/K^(+)-ATPase,ACSS2,acyl-CoA short-chain synthase 3(ACSS3),3-hydroxy-3-methylglutaryl-CoA lyase(HMGCL)and acetyl-CoA acetyltransferase 1(ACAT1)in ruminal epithelium of SARA group were significantly up-regulated(P<0.05).In conclusion,SARA can increase the mRNA relative expression levels of NHE1,NHE3,MCT1,DRA,ACSS2,HMGCS1,HMGCS2 and HMGCR in ruminal epithelium and the protein relative expression levels of NHE1,NHE3,NHE4,MCT2,AE2,Na^(+)/K^(+)-ATPase,ACSS2,ACSS3,HMGCL and ACAT1,there by accelerate the absorption and metabolism of VFA in ruminal epithelium and relieve the damage to the body of SARA.