Introduction: Radiotherapy is an important therapeutic manner of a wide range of tumors. Its side effects on normal cells limit the efficiency of therapy.
Aim of the work: To evaluate the protective role of daidzein and/or vitamin C against biochemical, histopathological and ultrastructural changes in male albino rats exposed to gamma radiation (γ-radiation).
Materials and Methods: The whole-body exposed to 8 GY γ-radiation. Daidzein was given to rats at a concentration of 63 mg/kg b.wt./day for 7 days before irradiation and 7 days during exposure. Whereas vitamin C was ingested at a concentration of 5 mg/kg b.wt. /day for 7 days before irradiation and 7 days during exposure. Animals were sacrificed on the 1st day post the irradiation dose. Blood samples were collected for biochemical determination of uric acid, urea, and creatinine. Lipid peroxides (TBARS) concentration and the activities of superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were also measured. Samples from the kidney were processed for light and electron microscopy.
Results: Irradiation induced significant elevation in uric acid, urea, creatinine and TBARS. These changes were accompanied by significant decrease in antioxidant status (SOD, CAT, and GPx). Also, the histological and ultrastructural investigation displayed remarkable changes in kidney tissue. Daidzein and /or vitamin C reduced the kidney damage induced by irradiation; this was showed by declined levels of creatinine, urea and uric acid, in addition to increased CAT, GPx, and SOD activities. The histopathological structure and ultrastructural alternations were also improved. The radioprotection index for the combination of daidzein and vitamin C was found to be more than daidzein or vitamin C separately.  Conclusion: Daidzein and vitamin C might modulate radiation damages to kidney by boosting the antioxidant capacity and attenuating oxidative injury.