Radiation protection by Shigoka extract on split-dose irradiation in mice

Radioprotective effect of a Shigoka extract was studied on split-dose irradiation. Mice were exposed to 4 Gy X 4 or 3 Gy X 4 for examining survival ratio or hemogram, respectively. The extract was i.p. injected immediately after each irradiation. The extract significantly (p less than 0.001) increased the survival ratio, and it increased leukocyte count within the period of the death (days 2-12 after the final exposure). Cerebral hemorrhage after 4 Gy X 4 was diminished by the extract. Recovery of leukocytogenesis seems much more important for survival at split-dose irradiation than at single acute irradiation.