灌喂氧化鱼油使草鱼肠道黏膜胆固醇胆汁酸合成基因通路表达上调

以草鱼(Ctenopharyngodon idella)为试验对象, 灌喂氧化鱼油7d后, 采集肠道黏膜组织并提取总RNA, 采用RNA-seq方法, 进行氧化鱼油组和正常鱼油组草鱼肠道黏膜基因差异表达水平、基因注释和IPA基因通路分析, 并测定了血清中胆固醇、甘油三酯、高密度脂蛋白和低密度脂蛋白含量. 研究结果显示, 草鱼肠道黏膜在受到氧化鱼油损伤后, 胆固醇和胆汁酸生物合成通路代谢酶、调节胆固醇和胆汁酸合成或转运的代谢酶或蛋白基因差异表达, 部分基因差异表达达到显著性上调水平. 实验结果表明, 草鱼肠道黏膜具备完整的乙酰辅酶A胆固醇胆汁酸的合成代谢基因通路. 肠道黏膜在受到氧化鱼油损伤后, 以乙酰辅酶A为原料的胆固醇生物合成代谢通路基因表达增强, 胆固醇由细胞外转运到细胞内的逆转运途径基因通路表达下调, 胆固醇由细胞内向细胞外转运基因通路表达上调; 以胆固醇为原料的胆汁酸经典合成代谢途径基因通路表达上调, 而胆汁酸的补充合成途径基因表达下调. 在灌喂氧化鱼油后, 血清胆固醇、低密度脂蛋白、甘油三酯含量分别增加了28.84%、29.56%和12.13%, 而高密度脂蛋白含量下降了8.15%.  

Feeding grass carp (Ctenopharyngodon idellus) with oxidized fish oil up-regulates the gene expression in the cholesterol and bile acid synthesis pathway in intestinal mucosa

In this study, grass carps Ctenopharyngodon idellus were injected with oxidized fish oil (experimental group) and normal fish oil (control group) continuously for 7 days. We collected the intestinal mucosa and extracted the total RNA the tissue, and then obtained the RNA sequences from both groups by using the RNA-seq method. We analyzed the differential gene expression, gene annotation, and IPA gene pathway, and measured the levels of cholesterol, triglycerides, HDL, and LDL in serum in the meanwhile. The gene expression in the cholesterol and bile acid biosynthesis pathways increased significantly ( 2 folds) when the intestinal mucosa was injured by oxidized fish oil. Our analysis revealed a complete acetyl coenzyme A cholesterol bile acid biosynthesis gene pathway in the intestinal mucosa of grass carps. Damages in the intestinal mucosa were demonstrated and they were clearly associated with oxidized fish oil. The overall gene expression in the cholesterol biosynthesis pathway was enhanced after the injury. The gene expression was reduced in the reverse cholesterol transporting pathway; in contrast, the gene expression in the cholesterol transport pathway was up-regulated which implied that more cholesterol could be transported out the cell. There was an increase in the gene expression in the classical pathway of bile acid biosynthesis that utilized cholesterol as a raw material; however, the expression in its supplementary pathway was decreased. The levels of cholesterol, LDL, and triglyceride in serum were increased by 28.84%, 29.56% and 12.13% respectively, whereas the level of high-density lipoprotein was reduced by 8.15%.