Effect Of X-ray Irradiation On NADH Dehydrogenase Activity And MtDNA Complexes â…  Gene Sequences

Objectives1. To investigate the effects of different doses of X-ray irradiation on NADHdehydrogenase activity of human esophageal squamous carcinoma Ec9706cells.2.To analyse the effects of6Gy X irradiation on the six gene (NDl,ND2,ND3,ND4, ND4L,ND5) sequences of mitochondrial DNA(mitochondrialDNA，mtDNA) complexⅠ.Methods1.The EC9706line of human esophageal squamous cell carcinoma cell werecultured in vitro，respectively2Gy,4Gy,6Gy,8Gy five dose irradiation.Extraction themitochondria mitochondrial enzyme activity after irradiation,selection of the bestdose group in final.2.MtDNA was extracted by6GyX irradiation in cell line Ec9706,afteramplification,using PCR technology,the PCR products were purified,and the PCRproduct recovery,purification.3.Genetic sequencing of the mtDNA NDl, ND2,ND3,ND4,ND4L,ND56gene.4.And compared with the analysis of DNA sequence variation of software on the NDl,ND2,ND3,ND4,ND4L, ND5.Results1. According to statistics analysis：After2Gy,4Gy,6Gy,8Gy different doses ofirradiation,the NADH dehydrogenase activity was significantly different between thegroups (P <0.05)；the NADH dehydrogenase activity in6Gy group was significantlylower than that in other four groups (P <0.01).2. After the6Gy X-ray irradiation,the six gene(NDl, ND2, ND3, ND4, ND4L,ND5) sequence of mtDNA did not change.Conclusions1. After2Gy,4Gy,6Gy,8Gy X-ray irradiation,the NADH dehydrogenase of Ec9706cell activity was lower than that in the non-irradiated group,from2Gy to6Gy,as thedose increased activity gradually decreased to a minimum when the6Gy dose；whendose was gradually increased to8Gy,although the activity lower than the controlgroup，but no longer continue to decrease.Further confirmed that the irradiation canaffect mitochondrial oxidative phosphorylation function.2.After6Gy X-ray irradiation，the six gene(NDl,ND2,ND3, ND4, ND4L, ND5)sequence of mtDNA did not change.