Use of combinations of chemioprotectors for protection from radiation genetic injury

The cytostatic agent thalliblastine (hydrochloride of the alkaloid thallicarpine), used solely or in combination with gamma-ray exposure, was studied in vitro for effects on the chromosome apparatus of lymphocytes from human peripheral blood. In combined treatment, thalliblastine at concentration levels of 1, 5, 10, 15 or 20 mcg/ml was applied immediately upon single acute exposure to 2 Gy, the drug thus acting throughout the interphase and prophase of the cell cycle. Cytogenetic analysis of metaphase 1 lymphocytes indicated thalliblastine alone to produce chromosome aberrations in excess of spontaneous frequency, with chromosome and chromatid fragments predomonating. The increase was shown to be statistically significant for 5 mcg/ml thalliblastine only. A concentration of 20 mcg/ml being toxic, culture growth was depressed in this case. Combined treatment was observed to produce an additive effect, with radiation playing the determining role. For thalliblastine at 10 mcg/ml, effect enhancement was noted, as clearly evidence in chromatid aberration yield. (authors)