Host: The Japan Radiation Research Society
Co-host: Asian Association for Radiation Research
Ionizing radiation generates reactive oxygen species (ROS), such as superoxide, hydroxyl radicals and hydrogen peroxide, which participate in DNA damage and lipid peroxidation. Manganese (III) -5,10,15,20-tetrakis (1-methyl-4-pyridyl) porphyrin pentachloride (MnTMPyP) is well known as cell-permeable superoxide dismutase (SOD) mimetics. In this study, we investigated the protective effects of MnTMPyP on the mortality after irradiation. Eight-week-old female ICR mice were given whole-body irradiation with 137Cs γ-rays at a dose of 8.2 Gy (0.93 Gy/min). Mortality of the irradiated mice was determined for 30 days after exposure. When the mice were given a single i.p. injection of MnTMPyP at a dose of 6, 60 mg/kg, or saline before irradiation, the survival rates were about 40%, 50% and 10%, respectively. The survival rate of group continuously treated with 6 mg/kg MnTMPyP for 2 weeks was about 50%. These results support that MnTMPyP might be a potential radioprotector. The conceivable mechanism of the radioprotective effect of MnTMPyP would be the scavenging of the free radicals because MnTMPyP has ROS scavenging activity. Effect of MnTMPyP after irradiation on the mortality is now underway.
