[Effect of heparin on postradiation thymus recovery in mice with various degrees of radiosensitivity]

BALB/c, random-bred and hybrid (CBA x C57Bl) F1 mice were exposed to a total single irradiation with CO60 gamma-rays (0.2 Gy/min) in doses of 4--6 Gy. Upon sublethal irradiation changes in the thymus mass were biphasic in nature. At the same time the degree of a secondary decrease in the thymus mass depended on radioresistance of the mice. On the 20th day after the irradiation the thymus mass in BALB/c mice (LD50/30 -- 6 Gy) reduced 3-fold, while that in mouse hybrids (LD50/30 -- 7 Gy) 2-fold. Upon heparin injection from day 5 to day 9 after the irradiation (250 units/kg once a day) the postradiation pattern of thymus mass recovery in radiosensitive BALB/c mice was similar to that seen in more resistant F1 hybrids.