氧化型和正常极低密度脂蛋白对猪主动脉平滑肌细胞脂类堆积的不同影响  

The Effect of Oxidized and Normal Very Low Density Lipoprotein on Lipid Accumulation in Porcine Aortic Smooth Muscle Cells

作　　者：杨宇虹[1] 冯宗忱[1] 王淳本[1] 江卫国[1] 赵小松 

机构地区：[1]同济医科大学生物化学教研室,武汉430030

出　　处：《中国动脉硬化杂志》1998年第4期305-309,共5页Chinese Journal of Arteriosclerosis

基　　金：国家"八五"攻关课题!859150304

摘　　要：为了观察氧化型及正常极低密度脂蛋白对血管平滑肌细胞内脂类堆积的不同影响，探索平滑肌细胞摄取氧化型极低密度脂蛋白的受体途径，用200mg/L的氧化型及正常极低密度脂蛋白与猪主动脉平滑肌细胞温育48h后，细胞内甘油三酯含量分别为对照组的3．2倍和10．6倍（P〈0．01），且两个实验组之间相比，差异也有显著性意义（P＜0．01）；细胞内总胆固醇明显升高（P＜0．05）．但是两个实验组之间无显著差异（P＞0．05）。荧光素异硫氰酸酯标记的氧化型极低密度脂蛋白结合试验表明；平滑队细胞可通过低亲和力受体途径可饱和性地摄取完整的氧化型极低密度脂蛋白（Kd＝48．82mg／L，Bmax＝2067μg／g）。与正常极低密度脂蛋白相比（Kd＝37．17mg／L，Bmax＝2596μg／g），Kd值升高，Bmax值减小。竞争抑制实验表明，氧化型极低密度脂蛋白、正常极低密度脂蛋白及正常低密度脂蛋白均对荧光素异硫氰酸酯标记的氧化型极低密度脂蛋白的结合摄取表现出明显的竞争作用（50％），而乙酰化低密度脂蛋白仅能抑制10％。提示氧化型极低密度脂蛋白通过低密度脂蛋白受体和／或极低密度脂蛋白受体途径进入平滑肌细胞。Aim To observe the different effects of oxidized very low density lipoprotein(ox-VLDL)and normal VLDL(n-VLDL)on lipid accumulation in smooth muscle cells(SMCs)and attempt to explore receptor pathway of ox-VLDL uptaken by SMCs.Methods The same concentration of ox-VLDL or n-VLDL was incubated with porcine aortic SMCs for 48 hours,total cholesterol(TC)and triglyceride (TG) of the cells were extracted and determined.SMCs were incubated at 37℃ in RPIM 1640 contain-ing different concentration of FITC-ox-VLDL or FITC-n-VLDL for 4 hours,the cells were washed with phosphate buffered saline and the cell surface bound lipoproteins were determined by fluorospec- trometry.Competition experiments were performed as above.except for adding different concentration of unlabeled lipoproteins into the medium.Results ox-VLDL or n-VLDL(200mg/L)was in-cubated with porcine aortic SMCs for 48 hours,caus-ing a 3.2- and 10.6- fold increment of cellular TG in SMCs respectively(p<0.01).less TG was ac cumulated with ox-VLDL as compared with n-VLDL (P<0.01).Scatchard plot of the data of binding ex-periment showed that the Kd of the binding of ox-VLDL or n-VLDL on SMCs were 48.82mg/L and 37.17mg/L respectively,and the Bmax was 2067 μg ox-VLDL/g cell protein and 2596μg n-VLDL/g cell pro-tein respectively.nLDL competed with FITC-ox-VLDL on binding to SMCs as efficient as ox-VLDL,however,acetyl LDL inhibited only 10%.Conclusion More TG was accumulated in cells ex-posed to n-VLDL(P<0.01).FITC-ox-VLDL and FITC-n-VLDL were taken up by SMCs via saturable mechanism with low affinity.The Kd of the binding of ox-VLDL on SMCs was greater than that of n-VLDL and the Bmax was lower than that of n-VLDL.nLDL competed with FITC-ox-VLDL on binding to SMC as efficient as ox-VLDL,acetyl LDL exhibited low competitive effect,indicating that,ox-VLDL was taken up by SMC via LDL or VLDL receptor.

关 键 词：VLDL 动脉粥样硬化 平滑肌脂类堆积 

分 类 号：R543.502[医药卫生—心血管疾病]