Abstract: The paper is mainly about to observe the effect of Radix Angelicae Sinensis and Radix Hedysari (RAS-RH) on hepatoma cells H22 DNA damage induced by heavy ion ¹²C⁶⁺ irradiation, and to explore its possible mechanism. H22 cells were cultured in DMEM medium.They were then divided into control group, drug group(RAS-RH), radiation group(Gy) and combination group(RAS-RH + Gy). CCK-8 method, single cell gel electrophoresis, γ-H2AX immunofluorescence in situ hybridization and Western Blotting were used to study the correlation. The results showed that RAS-RH inhibited the proliferation of human hepatocellular carcinoma H22 cells in a time-and dose-dependent manner at concentrations of 0-72 h and 5-200 mg/L. The IC20 of RAS-RH was (117.6+2.15) mg/L. Single cell gel electrophoresis showed that the content of Head DNA in the combined group was higher than that in the radiation group, while Tail DNA, TM and OTM were lower than those in the radiation group. RAS-RH did not increase DNA damage induced by heavy ion ¹²C⁶⁺ radiation, but in 2-12 h, the repair of double strand breaks of DNA by γ-H2AX foci was inhibited by RAS-RH, and DNA damage persisted. Western Blotting showed that RAS-RH inhibited the aggregation of γ-H2AX by down-regulating the expression of Ku70/80 and Rad51 proteins. It was suggested that RAS-RH could down-regulate the expression of DNA damage repair related factors Ku70/80 and Rad51 in human hepatocellular carcinoma H22 cells.

Key words: RAS-RH, heavy ion ¹²C⁶⁺, hepatoma cells line H22, DNA damage repair