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.