茶多酚对高蛋氨酸饮食大鼠GSH-Px、NOS活性及MDA、NO含量的影响

Effects of tea polyphenols on the activity of GSH-Px and NOS,and the content of MDA and NO in rats fed with high methionine diet

目的探讨茶多酚(TP)对高蛋氨酸饮食大鼠谷胱甘肽过氧化物酶(GSH-Px)、一氧化氮合酶(NOS)活性及丙二醛(MDA)、一氧化氮(NO)含量的影响。方法将大鼠随机分为对照组,模型组,TP低、中和高剂量组;对照组喂饲正常基础饲料,模型组及TP组均喂饲3%高蛋氨酸饲料,TP低、中、高剂量组每天经灌胃分别给予50、100和200mg/kg TP,对照组和模型组经灌胃给予等容量的蒸馏水。8周后断头处死大鼠,苏木素-伊红(HE)染色观察主动脉弓结构改变;试剂盒测定血清GSH-Px及NOS活性、MDA及NO含量。结果各组GSH-Px活性均无统计学差异;与模型组相比,TP低剂量组MDA含量下降27.1%(P<0.01),TP各剂量组NOS活性分别上升18.7%、15.1%、18.0%(P<0.01),TP低高剂量组NO含量分别增高113.4%和73.4%(P<0.01)。HE染色显示模型组动脉壁增厚,平滑肌增生,TP中高剂量组可抑制平滑肌增生。结论 TP可降低高蛋氨酸饮食引起的脂质过氧化水平,并通过提高NOS活性和NO含量维持内皮细胞的正常功能。

Objective To study the effect of tea polyphenols（TP） on the content of malondialdehyde（MDA） and nitric oxide（NO） and the activity of GSH-Px and nitric oxide synthase（NOS） in rats fed with high methionine diet.Methods Wistar rats were randomly divided into 5 groups： model group,control group and 3 TP groups.Rats in model group and TP groups were fed with 3% methionine in diet,and rats in control group with routine diet.Rats in low-,midium-and high-dose TP groups were treated with 50,100 and 200mg/kg TP respectively by gavage every day for 8 weeks.Rats in control group and model group were given equal volume of distilled water.Activities of GSH-Px and NOS and contents of NO and MDA in serum were detected.Histopathological changes of aortic arc were observed by hematoxylin-eosin（HE） staining techniques.Results There were no statistically significant changes of GSH-Px activities among all groups.Compared with model group,MDA contents decreased by 27.1% in low-dose TP group（P0.01）.Activities of NOS in TP groups increased respectively by 18.7%,15.1% and 18.0%（P0.01）,and NO contents in low-and high-dose TP groups increased by 113.4% and 73.4%（P0.01）,respectively.A proliferation of vascular smooth muscle cells（VSMC） and increased thickness of aortic arch was observed in rats of model group,and these changes were suppressed in TP groups.Conclusion Lipid peroxidation induced by high-methionine diet could be protected by TP.The function of endothelial cells could be maintained by increasing the NOS activity and NO contents,thus the injury of endothelial cells induced by high-methionine diet could be prevented and reduced by TP.