Beneficial effects of vitamin E on radioiodine induced gastrointestinal damage: an experimental and pathomorphological study.

OBJECTIVES: The aim of the present study was to investigate the radioprotective effect of vitamin E in the prevention of radioiodine (RAI) induced gastrointestinal damage. METHOD: Twenty-four rats were randomly divided into three groups as follows: Group-1 was untreated control group, Group-2 was orally administered single dose of 111 MBq RAI, and Group-3 was orally administered 111 MBq RAI and 1 mL of oral vitamin E. Vitamin E was started two days before RAI administration and was continued for five days once daily after RAI. Pathomorphological parameters of gastrointestinal tissues (stomach, small intestines and bowels) were measured using Hematoxylin-Eosin and Masson's trichrome staining. RESULTS: Varying degrees of inflammation, edema, ulcer, mucosal degeneration, necrosis and fibrosis were seen in the stomach, small intestine and bowel tissues of the rats in both study groups and not in the control group. The differences were statistically significant between these groups for all parameters (p < 0.05). The histopathological damage in the vitamin E treated group was significantly less than the damage in the RAI only group (p < 0.05 for all pathomorphological parameters). CONCLUSION: The results of this study showed that vitamin E has a radioprotective property with antiinflammatory and antifibrotic effects protecting against gastrointestinal damage caused by radioiodine (Tab. 3, Fig. 3, Ref. 26).

The protective effect of melatonin on sperm quality in rat after radioiodine treatment.

This study was designed to investigate the potential radioprotective impact of melatonin on the testicular tissue and sperm quality in rat given radioactive iodine (RAI) therapy. Thirty-six male Wistar albino rats were randomly divided into three groups as untreated control (Group 1); oral radioiodine group (RAI, 111 MBq, administrated rats); and RAI+melatonin group (oral radioiodine and intraperitoneal 12 mg/kg/day melatonin, starting 2 days before and continuing for 1 week after oral RAI administration). Twenty-four hours after the injection of the last melatonin dose, blood samples were taken for hormone analyses and the determination of the total antioxidant capacity. Sperm samples taken from the cauda epididymis were examined for spermatological parameters. Tissue samples taken from the rat testes were stained by TUNEL assay and with haematoxylin-eosin to detect apoptosis and histological alterations. It was demonstrated a significant decrease in epididymal spermatozoa viability and motility in all of the treatment groups, in comparison with the control group (p < .001). A significant decrease was also detected in sperm DNA fragmentation, follicle-stimulating hormone (FSH) level and the index of apoptotic germ cells in the RAI+melatonin group when compared to the radioiodine group. It was concluded that melatonin prevents the adverse affects of RAI on apoptosis and spermatozoa quality.

Melatonin: a hepatoprotective agent against radioiodine toxicity in rats.

OBJECTIVES: The aim of the current study was to investigate the possible radioprotective effects of melatonin against hepatic radioiodine (RAI) toxicity. METHODS: Thirty-six rats were randomly divided into three groups: untreated control (Group 1); oral radioiodine (RAI, 111 MBq) administrated rats (Group 2), and melatonin group (oral RAI and daily intraperitoneal injection of 12 mg/kg melatonin-Group 3). In the third group, melatonin administration was started two days before and continued for five days after RAI administration. Twenty-four hours after the administration of the last dose of melatonin, liver samples were taken for biochemical and histopathological evaluation. RESULTS: Oxidative stress parameters demonstrated that melatonin treatment decreased the tissue malondialdehyde (MDA), advanced the oxidation protein products (AOPP) levels, and increased the total-SH (sulphydryl) levels when compared with RAI group. The differences were statistically significant between these groups for all parameters (p < 0.05). The histopathological damage in the melatonin-treated group was significantly less than the damage in RAI group (p < 0.05 for all pathological parameters). CONCLUSION: The results of this study demonstrated that melatonin reduced the harmful effects of RAI treatment on the liver. Anti-inflammatory and antioxidant activities are likely to be involved in the mechanism underlying the radio-protective effects of melatonin (Tab. 3, Fig. 1, Ref. 30).