高脂饮食对小鼠胸主动脉平滑肌细胞凋亡率的影响及枸杞多糖的干预作用研究

Effect of High Fat Diet on Smooth Muscle Cell Apoptosis Rate of the Thoracic Aorta and the Intervention of Lycium Barbarum Polysaccharides

目的探讨高脂饮食对小鼠胸主动脉平滑肌细胞凋亡率的影响及枸杞多糖(Lycium Barbarum Polysacharides,LBP)的干预作用。方法健康雄性昆明小鼠34只,按体重随机分为正常对照组(10只)、高脂饮食组(12只)、高脂饮食+LBP组(12只)。正常对照组给予正常饮食60d,高脂饮食组、高脂饮食+LBP组均采用高脂饲料自由喂养60d;高脂饮食+LBP组于每天清晨9:00给予枸杞多糖80mg·(kg·d)-1灌胃,正常对照组、高脂饮食组于同时间点给予同剂量生理盐水灌胃,均持续30d。采用酶联免疫法检测小鼠血清总胆固醇(total cholesterol,TC)、甘油三酯(triglyceride,TG)、热休克蛋白70(Heat Shock Protein 70,HSP70)水平;采用721型分光光度计检测小鼠心脏组织匀浆超氧化物歧化酶(superoxide dismutase,SOD)及丙二醛(malondialdehyde,MDA)含量;采用原位细胞死亡检测法(TUNEL)检测小鼠胸主动脉平滑肌细胞凋亡率。结果与正常对照组比较,高脂饮食组、高脂饮食+LBP组小鼠血清TC、TG、心肌MDA及胸主动脉平滑肌细胞凋亡率均升高(P<0.05),心肌SOD降低(P<0.05),高脂饮食+LBP组HSP 70升高(P<0.05);与高脂饮食组比较,高脂饮食+LBP组小鼠血清TC、TG、心肌MDA均下降(P均<0.05),心肌SOD、血清HSP70、胸主动脉平滑肌细胞凋亡率升高(P<0.05)。结论高脂饮食可增加小鼠胸主动脉平滑肌凋亡率,降低心肌抗氧化应激能力,LBP通过抑制主动脉平滑肌细胞增殖和抑制脂质过氧化反应两种途径延缓动脉粥样硬化的发生、发展。

Objective To investigate the effect of high fat diet on smooth muscle cellapoptosis rate of the thoracic aorta and the intervention of Lycium Barbarum Polysaccharides(LBP). Methods Thirty-four Kunming mice were randomly divided into three groups: normal control group(ten),high fat diet group(twelve),high fat diet+LBP group(twelve). Mice of ormal control group was fed with normal diet for 60 days while mice of high fat diet group and high fat diet+LBP group were fed with high fat diet for 60 days. The high fat diet+LBP group received 80mg·(kg·d)-1LBP by gavage for 30 days. The normal control group and high fat diet group were given the same volume of isotonic saline solution by gavage for 30 days. At the end of gavage 30 days,blood samples were collected to measure the levels of total cholesterol(TC),triglyceride(TG),heat shock protein 70(HSP70)using ELISA. The homogenate of heart tissue was taken to measure the levels of malondialdehyde(MDA)and super oxide dismutase(SOD)by using the 721 type spectrophotometer; Thoracic aorta was taken to measure smooth muscle cells apoptosis rate by TUNEL. Results Compared with normal control group,the levels of TC,TG in serum,MDA in the homogenate of heart tissue,smooth muscle cells apoptosis rate of the thoracic aorta increased significantly in high fat diet group and high fat diet+ LBP group(P<0.05),SOD in homogenate of heart tissue decreased significantly in high fat diet group and high fat diet+LBP group(P<0.05)while HSP 70 in serum increased significantly in high fat diet+LBP group(P<0.05). Compared with fat diet group,the levels of TC,TG in serum and MDA in homogenate of heart tissue decreased significantly in high fat diet+ LBP group(P<0.05)while smooth muscle cells apoptosis rate of the thoracic aorta,HSP 70 in serum,SOD in homogenate of heart tissue increased significantly in high fat diet+ LBP group(P<0.05). Conclusion High fat diet could increase smooth muscle cells apoptosis rate of the mice thoracic aorta and reduce the ability to resist oxidative stress.LBP could delay the occurrence and development of atherosclerosis(AS) by inhibiting smooth muscle cell proliferation and lipid peroxidation.