Abdominal radiation initiates apoptotic mechanism in rat femur bone marrow cells in vivo that is reversed by IGF-1 administration.

PURPOSE Radiation induces apoptosis as a result of damage to cellular DNA and RNA. The aim of our work was to study the effect of radiation on rat bone marrow cells (as a neighboring tissue) in the context of a model of experimental radiation enteritis in rats. The effect of systematic administration in irradiated animals of r-IGF-1 and GH was also studied. MATERIALS AND METHODS Wistar type, normal rats, were divided in 4 groups. One control group and the other 3 groups were irradiated in the abdomen. The measured scattered irradiation in the femur ranged from 16.5 to 47.3 cGy. In 2 groups of irradiated animals, rIGF-1 (0.1 microg/g of body weight twice/d) and rGH (0.25 microg/g of body weight /d) were administered. Bone marrow cells were harvested from both femurs. DNA and RNA were analyzed in specific gels. The m-RNA was hybridized for c-fos proto-oncogene expression. RESULTS The calculated low dose of radiation that affected the femurs of the animals induced reduction in bone marrow cell numbers and endonuclease activation manifested by subsequent fragmentation of DNA and RNA. This phenomenon was reversed by rGH and rIGF-1 administration. The c-fos proto-oncogene expression was upregulated by irradiation. CONCLUSION These observations indicate that scattered low dose radiation is capable of initiating apoptosis in rat bone marrow cells and rGH and rIGF-1 administration reverse this process.