bcl-2 gene expression in splenocytes from gamma irradiated mice

We have shown earlier that chronic low-dose gamma irradiation induces the synthesis of stress proteins, and increases adaptive possibilities of cells. Here we analyse the expression of bcl-2 gene, whose product is thought to prevent apoptosis, in thymocytes and splenocytes an mice after exposure to gamma irradiation at a dose range from 3 cGy to 6 Gy. Gamma irradiation of mice at a dose rate of 3 cGy per day for 30 days gradually enhances bcl-2 gene expression. The overexpression of bcl-2 under conditions of a continuous gamma irradiation was shown to suppress apoptosis, induced by subsequent acute gamma irradiation at a dose of 6 Gy. Irradiation of mice at a dose of 6 Gy alone did not change bcl-2 mRNA level in thymus and slightly decreased in spleen. The interrelation between the antioxidant status of cell and radiation-modified bcl-2 gene expression in apoptosis is discussed. (author)