Metformin modulates cardiac endothelial dysfunction, oxidative stress and inflammation in irradiated rats: A new perspective of an antidiabetic drug.

Cardiovascular disease is one of the most pivotal disorders after radiotherapy. The aim of this study investigates the possible protective effect of metformin against gamma radiation-induced heart damage in male rats. Group 1 (control) received saline, group 2 was whole body gamma-irradiated 5 Gy, group 3 was orally administered metformin 50 mg/kg/day for 2 weeks, group 4 received metformin 50 mg/kg/day for 1 week, then exposed to whole-body gamma radiation at a dose of 5 Gy and continued with metformin for further 1 week. The results revealed that the administration of metformin to irradiated rats significantly ameliorated the changes in cardiac biomarkers (LDH and CK-MB) compared with irradiated group. Heart catalase and SOD activities showed normal level when compared with the irradiated group. Also, NF-κB, IL-6 and TNF- α levels were markedly decreased compared with the corresponding values of irradiated group. Consequently, metformin reduced E-selectin as well ICAM and VCAM-1. These results confirmed by histopathological examination. In conclusion, concomitant administration of metformin during radiotherapy acts as a potent heart protector from oxidative stress, inflammatory mediators and endothelial dysfunction induced damages. Results thus hold a great promise for a new implication of an antidiabetic drug (metformin) as adjunct to radiotherapy.