The effect of thymic humoral factor upon regeneration of lymphatic and haemopoietic tissues of irradiated mice.
The study investigates the effect of humoral factor isolated from calf-thymus (thymosin) upon regeneration of lymphatic and haemopoietic tissues of female (CBA times C57BL/10ScSn)F1 mice irradiated with a whole-body exposure of 500R or 600R of gamma-rays. Thymosin was applied subcutaneously in amounts of 5 mg. per mouse per day. Two schemes of application were used: 1. The first dose given immediately after irradiation, followed by one injection daily for a total of either 3 or 9 days. 2. The first dose given 3 days prior to radiation exposure, followed by one injection daily for a total of 7 days. The number of endogenous spleen colonies, 59Fe splenic uptake, and dry spleen weight, all estimated on day 9 postirradiation, were significantly higher in both experimental groups treated with thymosin, when tested against untreated controls. If the start of the treatment preceded the irradiation, the ESC number increased as much as five times beyond the level found in the irradiated untreated group and the 59Fe uptake even exceeded the values of iron incorporation in unirradiated mice. Stimulation of lymphopoiesis induced by thymosin was reflected in an increase in 2-(14)C-thymidine incorporation into DNA of the spleen, thymus and lymph nodes, measured 72 hours after irradiation.
D000818:Animals; D002999:Clone Cells; D005260:Female; D005720:Gamma Rays; D006413:Hematopoietic System / Q000276:immunology* / Q000528:radiation effects; D008208:Lymphatic System / Q000276:immunology* / Q000528:radiation effects; D051379:Mice; D013154:Spleen / Q000166:cytology / Q000276:immunology / Q000528:radiation effects; D013947:Thymosin / Q000008:administration & dosage / Q000494:pharmacology*; D013949:Thymus Extracts / Q000494:pharmacology*
D013949:Thymus Extracts; D013947:Thymosin