Radioprotective effect of adenine on irradiation-induced apoptosis

AIM:To investigate the radioprotective effect of adenine on irradiated lymphocytes and discover the possible mechanisms of protection.METHODS:Lymphocytes were pretreated for 12 h with adenine(0.001-0.1 molL-1) and then exposed to 4 Gy radiation.Cell viability was observed by the MTS assay,apoptosis was detected by Annexin V-FITC/PI,DNA ladder,and caspase 3/7 activity.Caspase-9,Bax,and Bcl-2 gene expression was investigated by RT-PCR.RESULTS:Irradiation increased cell death and DNA fragmentation.Pretreatment with adenine significantly reversed this tendency.Furthermore,several anti-apoptotic characteristics of adenine were determined,including the ability to inhibit caspase 3/7,upregulate B-cell lymphoma(Bcl-2) and downregulate Bcl-2-associated X(Bax),capase-9 gene expression in 4 Gy-irradiated AHH-1 cells.CONCLUSION:The results suggest that adenine had a radioprotective effect to inhibit apoptosis in a concentration dependent manner.