Anti-oxidative Effects of Melatonin in Protection Against Renal tubular Damage Caused By Ionizing Radiation In Mice (Histological and electron microscopical studies)

摘要

The response to ionizing radiation, at the cellular level, depends on a number of factors that may be grouped into those that are genetically controlled, radiation quality, dosage, and environmental factors. The biological effects of low levels of ionizing radiation, and regulatory measures to protect people from exposure to low doses, have come in for much scrutiny in recent years. The objective of this study is to examine the potential radioprotective properties of melatonin in exposed low dose irradiated mice. Kidney, is selected to study the effect of low dose gamma irradiation as it is a target organ of many other organs, which influence its function. Histopathological, and electron microscopical changes of the renal tubular structure of the kidney were studied in irradiated, and melatonin treated animals. Male adult albino mice were used in this experiment, they were divided into 5 main groups: the first was, served as control normal group. The 2nd was given-in a fractionated dose of gamma radiation at a dose level (? Gy) twice a week for eight weeks, while the third were left 8 more weeks without radiation. The 4th group was given daily intraperitoneal, i.p. 10 mg/kg melatonin and irradiated by ? Gy twice a week for eight weeks, and the 5 th was left 8 more weeks given melatonin only without irradiation. (All groups of animals were scarified at two time intervals 8 and 16 weeks). It could be observed that The intensity of the histological damage was more marked in the untreated irradiated group which irradiated for 8weeks than those which are irradiated and left 8 more weeks without radiation irradiated. Hydropic change in the renal tubule, degenerative, narcotizing changes, and areas of complete proximal tubular necrosis and autolysis break down were detected. The protection offered by pretreatment with Mel. is particularly dramatic. . The proximal tubules retain its normality and structure; the nuclei were rounded with well- developed nuclear membrane and chromatin. On the other hand the distal tubules were well designed with many mitochondria and healthy nucleus. It could be reported that 10 mg/kg melatonin given Intraperitoneal, (i.p.) Daily to the irradiated animals helped very much the kidney to be protected from radiation injuries. The radioprotective effects of melatonin against cellular damage caused by radiation oxidative stress and its low toxicity make it a potential supplement in the treatment or co-treatment in situations where the effects of ionizing radiation are to be minimized