Study On Toxic Effects Of Combined Cadmium And UVB On Human Skin Fibroblasts

As the first defense of organisms,skin is chronically exposed to the natural environment which is prone to be attacked by various environmental factors such as irradiation and toxic compounds.UVB in the sunlight is one of the greatest harmful environmental factors to human skin.Cadmium(Cd)is a kind of harmful heavy metals that is widely distributed in the environment.Cadmium has long been classified as B1 carcinogen by the International Agency for Research on Cancer(IARC)[1]In cadmium-polluted areas,there will be a combination exposure of cadmium and UVB.Therefore study on the combined toxicity of cadmium and UVB is of practical significance.This study explored the joint toxicity of cadmium and UVB on human skin fibroblasts(GM00637).Methods:After exposure to different doses of cadmium(0-16 ?M)and UVB(10-100 mJ/cm2)of GM00637 for 24 h,the SRB assay was used to detect cell viability,flow cytometry(FCM)was used to detect cell cycle distribution and apoptosis,western blotting and immunofluorescence were used to detect DNA damage and the expressions of DNA damage and apoptosis-related factors respectively.Results:1.0.25-0.50 p.M cadmium treatment alone could stimulate GM00637 cells' proliferation.UVB treatment alone with doses of higher than 50 mJ/cm2 significantly inhibited cell proliferation.Doses higher than 1 ?M of cadmium significantly decreased cell viability.Combined treatment of cadmium and UVB significantly impaired cell viability and displayed joint toxicity.2.High doses of cadmium,UVB treatment alone and combined treatments of cadmium and UVB caused GM00637 cells' DNA damage and these effects were significantly higher than those of control and were dose-dependent.3.High doses of cadmium,UVB treatment alone and combined treatments of cadmium and UVB induced GM00637 cells'apoptosis were significantly higher than those of control and were dose-dependent.4.Lower concentrations of cadmium had no significant impact on UVB-induced GM00637 cells' cell cycle arrest(G1/S phase),and higher doses of combined treatments appeared to change cell cycle distribution.Conclusion:The cell viability of GM00637 cells were decreased by combined exposure of cadmium and UVB,combined treatment of UVB and cadmium enhanced DNA damage and apoptosis.