皮质酮处理对产蛋鸡肝脏胆固醇代谢的影响

Effects of Corticosterone Treatment on Hepatic Cholesterol Metabolism in Laying Hens

为研究慢性应激对产蛋鸡肝脏胆固醇代谢的影响,试验选用48只158日龄如皋黄鸡,随机分成2个处理组,每组8个重复,每个重复3只鸡。对照组注射等体积的生理盐水(含15%酒精),试验组注射4 mg/kg的皮质酮,连续注射7 d建立慢性应激模型。试验结束后对其血浆和肝脏中胆固醇含量以及肝脏中胆固醇代谢相关基因的mRNA和蛋白表达进行分析。结果显示:皮质酮处理显著促进了产蛋鸡肝脏重以及肝脏和血浆中总胆固醇含量(P<0.01),显著促进了产蛋鸡肝脏中胆固醇合成基因SREBP2和HMGCR的mRNA和蛋白表达水平(P<0.05),胆固醇降解基因CYP7A1的蛋白表达、CYP27A1和转运基因LDLR的mRNA和蛋白表达水平在皮质酮处理后亦显著上调(P<0.05)。研究表明,皮质酮通过上调肝脏中胆固醇合成基因SREBP2和HMGCR以及转运基因LDLR的mRNA和蛋白表达,进而造成产蛋鸡肝脏中胆固醇累积。

In order to study the effects of chronic stress on hepatic cholesterol metabolism in laying hens,a total of 48158-day-age Rugao yellow-feathered laying hens were randomly allotted into 2 treatments with 8 replicates,and 3 chickens per replicate.Hens were treated with daily subcutaneous injection of solvent(15%ethanol)or corticosterone(CORT)in a dose of 4.0 mg/kg body mass for 7 days to establish a chonic stress model.The plasma and hepatic cholesterol content and hepatic mRNA and protein expression of cholesterol metabolism related genes were analyzed after the experiment.The results showed that chronic CORT treatment significantly increased the liver weight,hepatic and plasma total cholesterol content(P<0.01),significantly increased the mRNA and protein expression of cholesterol biosynthesis genes SREBP2 and HMGCR in chicken liver(P<0.05),and the protein expression of cholesterol catabolic gene CYP7 A1 and the mRNA and protein expression of cholesterol catabolic gene CYP27 A1 and transporter gene LDLR were also significantly increased(P<0.05).The results showed that chronic CORT administration induced hepatic cholesterol accumulation in laying hens likely through increasing the mRNA and protein expression of cholesterol biosynthesis genes SREBP2 and HMGCE and transporter gene LDLR.