Intervention of astragaloside to human skin fibroblasts affected by ultraviolet A

Objective To discuss the mechanism of astragaloside intervening the ageing of human skin fibroblasts induced by the radiation of ultraviolet A(UVA).Methods Skin fibroblasts were cultured in vitro,irradiated with UVA(10 J/cm2) and then intervened with astragaloside(20 mg/L).After 24 h,48 h and 72 h,the changes of cell cycle distribution were detected by using flow cytometer,and after 24 h,the expressions of ageing-related genes p53,p16 and c-myc were detected by using real-time fluorescence quantitative polymerase chain reaction(RT-PCR).Results Compared with control group,there were obvious blocks in G1 phase of fibroblasts in UVA group(P0.01).After 24 h,the proportion of fibroblasts in G1 phase increased from 59.31% in control group to 81.36% in UVA group,and after 72 h,the proportion increased further to 89.09%.In astragaloside group,the blocks in G1 phase of fibroblasts were significantly alleviated(P0.01),and proportion of fibroblasts in G1 phase decreased to 69.14%.The results of RT-PCR showed that the expressions of p53 mRNA and p16 mRNA increased and expression of c-myc mRNA decreased in UVA group(P0.01).The expressions of p53 mRNA and p16 mRNA were inhibited(P0.01) and expression of c-myc mRNA was down-regulated in astragaloside group.The expression of c-myc mRNA was down-regulated further in UVA combining astragaloside group(combining group,P0.01).Conclusion The radiation of UVA can start the ageing process of skin fibroblasts through inducing the blocks in G1 phase.Astragaloside can inhibit this ageing process,and the mechanism may be related to regulating the expressions of ageing-related genes.