Radioprotective effects of benzene extracts of human blood cells in rats following chronic irradiation

Benzene extracts were prepared of blood cells from nine donors at the blood transfusion service. In three instances these extracts had a radioprotective effects against the action of long-term, 45-hour gamma irradiation with a dose of 15.4 Gy. The three extracts differed as to the optimal dose and the number of applications required to produce increased radioresistance. The optimal single dose of the first extract was 0.60 mg . kg-1 and of the third 0.10 mg . kg-1. The first two extracts were administered by the i. p. route to rats three times (36, 24 and 7 days or 43, 31 and 14 days before irradiation) and the third five times (36, 30, 24, 18 and 7 days or 43, 37, 31, 23 and 14 days before irradiation). The said properties of the extracts in the different donors were stable and persisted ever after repeated blood sampling. Survival up to the 30th day after the end of irradiation was on average by 45 percentage higher in animals receiving the extracts than in the controls. (author)