Biochemical Evaluation of Serum CK18 (M30/M65) Levels and Radioprotective Effect of Melatonin in Rats Irradiated at Different Dose Rate

Abstract

Purpose: This study aims to biochemically assess serum CK18 levels in healthy rats exposed to FF and FFF mode irradiation. Additionally, the radioprotective effect of melatonin against two different dose rates will be evaluated. A total of 48 healthy adult female Sprague Dawley rats were included in this experimental study. Rats in Groups 1 and 2 did not receive any radiotherapy. Groups 3 and 5 were exposed to radiotherapy alone at dose rates of 600 MU/min (LDR-FF) and 2400 MU/min (HDR-FFF), respectively. Group 4 received 50 mg/kg of melatonin (MLT) 15 minutes prior to LDR-FF irradiation, while Group 6 was administered the same dose of MLT 15 minutes before HDR-FFF exposure. A significant increase in M30 and M65 levels was observed in Groups 3 and 5 as a result of radiation exposure. In both irradiated groups, melatonin treatment led to a reduction in these biochemical parameters. The findings demonstrate significant changes in serum M30 and M65 levels following melatonin administration, highlighting its potential as a radioprotective agent. CK18-based biomarkers are suggested for broader use in future preclinical and clinical research.