The radioprotective effect of vitamins C, E and vitamin E + glutathione on the small intestine and the thyroid gland in rats irradiated with X-rays

This investigation was carried out in order to determine the protective effects of long term administration at supraphysiologi- cal doses of vitamin E, vitamin C and a compound of vitamin E + glutathione against damage induced by free radicals produced by ionizing radiation. Five groups of 8-10-week-old Wistar albino rats were used in the study. Group I was the sham group and Group II was the radiation group (i.e. radiation alone). The rats in Group III were given a daily dose of 400 mg/kg of vit. C for one month. The rats in Group IV were given a daily dose of vit. E for one month. The rats in Group V received a mix- ture of 400 mg/kg vit. E plus 1000 mg/kg of glutathione per day for 15 days. All the com- pounds were administered via a nasogastric tube. At the end of the drug administration period, the rats in all but the sham group were exposed to X-ray with an radiation ener- gy dose of 8.90 Gy. All the rats were sacri- ficed 1 day after irradiation. Thyroid and intestinal tissues were examined for histopathological changes and T3 , T4 , TSH hormone levels were determined by radioim- munoassay (RIA). The radiation damage observed in the thy- roidal and intestinal cross-sections of the Group II rats was also seen to a lesser extent in the Group III (vit. C group) and Group IV (vit. E) rats. Toxic effects were observed in the Group V (vit. E + glutathione) rats. Significant T3 and TSH level changes (p<0.001; p<0.01) were observed in the Group II rats (radiation alone) and the levels of these hor- mones appeared to be partly affected in the rats in Group III (vit. C group) and Group V (vit. E + glutathione), albeit insignificantly (p>0.05).