Protective effect of melatonin on hemoglobin damage induced by gamma irradiation

Ionizing radiation causes serious damage in biological system. Some drugs and antioxidants are used to prevent such damage. In the present study two doses of melatonin (10 mg/kgand30mg/kg) were selected to be used for such purpose. The radioprotective effects of melatonin on hemoglobin of red blood cells from female mice was studied through UV absorption spectrum, ESR spectroscopy, dielectric measurements and relative viscosity .The results of Hemoglobin absorption indicate that a pronounced increase in the average value of peak position and width at half maximum Whmax followed by a decrease in the absorbance of sort band, decrease in absorption ratio A578 / A540 in addition to disappearance of globin band at 275 nm. The free radicals which are expected to be formed after exposing to γ-irradiation are detected by electron spin resonance spectroscopy (ESR). The results indicate that the intensity of ESR signal for hemoglobin extracted from animals exposed to γ-irradiation is greater as compared with normal hemoglobin. Dielectric measurements indicate that there is an increase in dielectric permittivity (e'), the dielectric loss (e'') and the a.c conductivity (σac) while some decrease is noticed in the viscosity measurements after exposing to irradiation. The data obtained from the whole studied parameters after treating animals with melatonin become closer to those for unirradiated samples.