Effect of Melatonin on Bone Mineral Density of Irradiated Rats

Objective: melatonin is a powerful endogenous antioxidant and it may play a role in prevention of radiation-induced damage. the aim of this study was to investigate the effect of melatonin on bone mineral density in rats receiving radiation. materials and methods: sprague dawley rats were divided into four groups. group 1 (control group) received neither melatonin nor radiation (control group). group 2 (mel group) was administered intraperitoneal injections of 5mg/kg melatonin daily for ten days. group 3 (rt group) and group 4 were exposed to total cranium radiation of 5 gy in a single dose by using a cobalt-60 teletherapy unit. in addition to irradiation, group 4 (rt + mel group) was administered 5mg/kg of melatonin intraperitoneally. at the end of the 10th day, the rats' cranium and vertebrae bone mineral densities (bmds) were measured. results: when cranial bmds were evaluated, statistically more significant bmd increases were seen in the mel group and the rt + mel groups than in the control group. no significant difference was seen in the mel group versus the rt + mel group; however, there was a significant difference between rt and rt + mel groups. when vertebral bmds were evaluated, the only significant difference was found between the control and mel groups. conclusion: we think that melatonin is a radioprotective agent. however, we would like to emphasize that further studies are needed before clinical trials with melatonin are initiated.