Abstract: Objective To study the protective effects of the polypeptides isolated from Chlamys farreri(PCF)against ultraviolet B radiatins.Methods An oxidative damage model of HeLa epithelial cell line irradiated by ultraviolet B(UVB 7.15×10^-5J/cm²)was established.The HeLa cells were randomly divided into six groups:control group,UVB radiated groups(radiated control,0.5%PCF,1%PCF,2%PCF,1%Vit C).The enzymic activities of HeLa cells were tested by MTT methods,the apoptosis rate and death rate of HeLa epithelial cells and the content of free calcium in those cells were tested by using flow cytometry(FCM).The contents of MDA and the activities of GSH-Px,SOD,CAT in the supernatants of cells were determin ed by biochemical methods.Results The results indicated that polypeptides from Chlamys farreri could enhance the activities of GSH-Px,SOD,CA T and decrease the contents of MDAin the supernatants of HeLa cells,increase the concentration of cellular free calciumin the cells,and decrease the rates of apoptosis and cell death of the cells.Conclusions The PCF has the protective effects on the HeLa cells irradiated by ultraviolet B.The mechanism of this effects of PCF may be mediated by eliminating the free radicals,by increasing the activities of antioxidative enzymes to inhibit the oxidative damages caused by UVB.

Key words: Polypeptides,Chlamys farreri, Ultraviolet rays, HeLa cells, Anti oxidants