Protection Against X-ray Irradiation Injury by Chinese Caterpillar Medicinal Mushroom, Ophiocordyceps sinensis (Ascomycetes) Polysaccharides in Mice

Polysaccharides are one of the main active ingredients of Ophiocordyceps sinensis, a traditional Chinese medicinal mushroom. In this study, we investigated the protective effect of O. sinensis polysaccharides (CSPs) against X-ray irradiation in mice. The results indicated that CSPs improved survival rates and times in radiation-injured mice, accelerated the recovery of white blood cells, increased the organ index of thymus and spleen, and increased the DNA content in bone marrow cells. CSPs also increased the activity of superoxide dismutase, decreased the production of malondialdehyde, and reversed the increase in catalase and glutathione peroxidase activity induced by irradiation. Treatment with 100, 200, and 400 mg/kg body weight CSPs caused a significant decrease in the protein and messenger RNA expression of extracellular regulated protein kinase (ERK1), c-Jun N-terminal kinase (JNK1), and p38 mitogen-activated protein kinase (MAPK) after irradiation. Our results demonstrate that CSPs protect mice from injury after exposure to X-ray irradiation, and that this effect may be exerted via the mitogen-activated protein kinase pathway. These findings may provide a basis for the use of CSPs as an effective radioprotector or an alternative strategy in reducing irradiation-induced injury.