枸杞多糖对高脂血症小鼠血脂及肝脏氧化应激的影响

Effects of Lycium Barbarum Polysaccharides on Blood Lipid and Oxidative Stress of the Liver in Hyperlipidemic Mice

目的探讨枸杞多糖(lycium barbarum polysaccharides,LBP)对高脂血症小鼠肝脏胆固醇7α-羟化酶(cholesterol 7-alpha hydroxylase,CYP7A1)mRNA表达及氧化应激功能的影响。方法选取健康雄性昆明种小鼠26只,随机分为正常对照组、高脂血症组、高脂血症+LBP组;除正常对照组给予正常饮食,高脂血症组、高脂血症+LBP组采用高脂饲料喂养法建立小鼠高脂血症模型;模型建立成功后,高脂血症+LBP组于每天上午9:00按80mg·(kg·d)-1LBP灌胃;正常对照组、高脂血症组在同样时间以同样容量生理盐水灌胃,持续灌胃30d。采用酶联免疫法测定血清总胆固醇(total cholesterol,TC)、甘油三酯(triglyceride,TG)、热休克蛋白70(heat shock protein 70,HSP 70)水平;采用吸光光度法测定肝脏超氧化物歧化酶(super oxide dismutase,SOD)、肝脏丙二醛(malondialdehyde,MDA)表达水平;采用实时荧光定量PCR技术测定肝脏CYP7A1mRNA表达水平。结果与正常对照组比较,高脂血症组小鼠血清TC、TG、肝脏MDA均升高(P<0.01),肝脏SOD、肝脏CYP7A1 mRNA表达水平均下降(P<0.01),高脂饮食+LBP组血清TC、TG、HSP70升高(P<0.01),而肝脏CYP7A1 mRNA表达水平则降低(P<0.05);与高脂血症组比较,高脂血症+LBP组小鼠血清TC、肝脏MDA均下降(P<0.01),肝脏SOD、肝脏CYP7A1 mRNA表达水平、HSP 70升高(P<0.05或P<0.01)。结论 LBP可提高高脂血症小鼠抗氧化应激能力,并可能通过上调高脂血症小鼠肝脏CYP7A1 mRNA的表达降低胆固醇。

Objective To investigate the effects of lycium barbarum polysaccharides( LBP) on cholesterol7-alpha hydroxylase( CYP7A1) mRNA expression and oxidative stress function of the liver in hyperlipidemic mice. Methods Twenty six Kunming mice were randomly divided into three groups: normal control group,hyperlipemia group,hyperlipemia + LBP group. When the mice model of hyperlipidemic was established by cholesterol diet feeding for 4 weeks,the hyperlipemia + LBP group received 80mg·( kg·d)^(-1) LBP by gavage for 30 days. Mice in the normal control group and hyperlipemia group were given the same volume of isotonic saline solution by gavage for 30 days. At the end of 30 days,the liver tissues were taken to measure the levels of malondialdehyde( MDA) and super oxide dismutase( SOD) by spectrophotometry. Blood was collected to measure the levels of total cholesterol( TC),triglyceride( TG),heat shock protein 70( HSP 70) by Enzyme-linked immunosorbent assay( ELISA). The liver tissues were taken to measure the levels of CYP7A1 mRNA expression by Real-time fluorescence quantitative PCR. Results Compared with mice in normal control group,the levels of TC,TG in serum,MDA in liver increased significantly in hyperlipidemia group( P <0. 01) while CYP7A1 mRNA expression decreased significantly in hyperlipidemia group( P < 0. 01). Compared with mice in normal control,the levels of TC,HSP70 in serum increased significantly in hyperlipemia +LBP group( P < 0. 01) while CYP7A1 mRNA expression decreased significantly in hyperlipemia + LBP group( P < 0. 05). Compared with hyperlipidemia group,the levels of TC in serum and MDA in liver decreased significantly in hyperlipemia + LBP group( P < 0. 01) while CYP7A1 mRNA expression,HSP 70 in serum,SOD in liver increased significantly in hyperlipemia + LBP group( P < 0. 05 or P < 0. 01 respectively).Conclusion LBP can improve antioxidant capacity of hyperlipidemia mice and may reduce blood cholesterol by increasing CYP7A1 mRNA expression in liver.