Bone marrow and intestinal damage limits the efficacy of radiotherapy for cancer and can result in death if the whole body is exposed to too high a dose, as might be the case in a nuclear accident or terrorist incident. Identification of an effective nontoxic biological radioprotector is therefore a matter of some urgency. In this study, we show that an orally administered hot-water extract from a Chinese herbal medicine, Cordyceps sinensis (CS), protects mice from bone marrow and intestinal injuries after total-body irradiation (TBI). CS increased the median time to death from 13 to 20 days after 8 Gy TBI and from 9 to 18 days after 10 Gy TBI. Although CS-treated mice receiving 10 Gy TBI survived intestinal injury, most died from bone marrow failure, as shown by severe marrow hypoplasia in mice dying between 18 and 24 days. At lower TBI doses of 5.5 and 6.5 Gy, CS protected against bone marrow death, an effect that was confirmed by the finding that white blood cell counts recovered more rapidly. In vitro, CS reduced the levels of free radical species (ROS) within cells, and this is one likely mechanism for the radioprotective effects of CS, although probably not the only one."

PURPOSE: This study was carried out to test the hypothesis that the anti-oxidant and growth promoting properties of the cultured mushroom fungus Hirsutella sinensis (CorImmune) of Cordyceps sinensis mitigate radiation injury in mice. MATERIALS AND METHODS: BALB/c mice received total body irradiation (TBI) followed by treatment with CorImmune. The effect of CorImmune on lymphoid tissue, spleen and blood cells as well as survival and hematopoietic recovery was compared to normal saline treated controls. RESULTS: CorImmune administered beginning 2 hours after a lethal dose of TBI significantly improved survival: 55% in the CorImmune group vs. 0% in the saline control (p < 0.0001). It increased normal leukocyte levels in a dose-dependent fashion. Animals treated with sub-lethal TBI and monitored for blood leukocyte recovery exhibited a return to normal baseline 3 weeks after TBI injury. In contrast, only 50% returned to normal baseline in the saline control group (p < 0.01). CorImmune also stimulated immune lymphocyte proliferation by nearly two-fold in a (3)H-thymidine incorporation assay compared to controls (p < 0.01). CONCLUSIONS: CorImmune significantly increased animal survival after a lethal dose of radiation, accelerated leukocyte recovery and stimulated immune lymphocyte proliferation. We conclude that CorImmune is effective as a radiation mitigator when administered after radiation injury.