Radioprotection of EGCG based on immunoregulatory effect and antioxidant activity against 60Coγ radiation-induced injury in mice

Excessive reactive oxygen radicals (ROS) produced by ionizing radiation (IR) can cause human body to serious oxidative damage, leading to oxidation-reduction (REDOX) system imbalance and immune system damage. Here, the radioprotection of EGCG was studied through a model of oxidative damage in 60Coγ radiation mice. Firstly, the weights and the main organs indexes of mice, including the liver index, spleen index and pancreas index, indicated preliminarily the safety and protection of EGCG. Then, the radioprotection of EGCG based on immune-regulation on radiation mice was further investigated. Results suggested that EGCG could prevent significantly the immune system damage caused by 60Coγ via increasing the immune organ index, inducing the transformation of spleen cells into T- and B-lymphocytes, and enhancing the macrophage phagocytosis, compared with model group. In addition, EGCG could also protect spleens of radiation mice from 60Coγ-induced the imbalance of REDOX system by enhancing the activities of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), increasing the level of glutathione (GSH), suppressing lipid peroxidation (Malondialdehyde, MDA). The antioxidant enzymes activities of serum and livers were also increased markedly. Taken together, our results indicated that EGCG possessed the excellent potential to serve as a natural radioprotector against IR-induced damage.