Purpose: The degree of radiation injury to kidneys which are located within the limits of radiotherapyarea is determined by the volume and the dose of radiation to which the organ is exposed. When the tolerancedose of the kidney is exceeded after a latent period of 6 months acute nephritis develops and after 18 monthschronic nephritis ensues. Melatonin is known to prevent the oxidative injury of toxins and radiotherapy withits free radical scavenging capacity. Methods and materials: In this study 8 weeks old 24 Sprague –Dawley ratswere allocated into 4 groups: Control group; Radiotherapy group (20 Gy bilaterally in 5 fractions); Melatoningroup (10 mg/kg intraperitoneally), and Melatonin+radiotherapy group (20 Gy Radiotherapy in 5 fractions+melatonin 10 mg/kg intraperitoneally). After a follow-up period of 6 months BUN was determined in all groups.After rats were euthanized the kidneys were removed for histopathological examination under both light andelectron microscopes.
Results: After 6 months follow-up, both at light and electron microscopy levels, therats in radiotherapy+melatonin group were significantly protected against the radiation injury comparing toradiotherapy group (p<0.05).
Conclusion: It was shown in this experimental model that melatonin has protectiveeffects against radiation injury to kidneys.