RADIOPROTECTIVE EFFECTS OF THE ASSOCIATION THYMOPENTIN INTERLEUKIN-1-ALPHA IN THE C57BL 6 MOUSE/

We investigated whether thymopentin, a synthetic pentapeptide derivati ve of thymopoietin, could enhance the protective effect of interleukin -1alpha when both administered prior to sublethal irradiation in the C 57BL/6 mouse. Thymopentin (10 mg/kg/day/7 days) was injected intraperi toneally in groups of C57BL/6 mice. Then, interleukin-1alpha was admin istered on day 7. Twenty hr later, all groups were given whole body su blethal irradiation of 750 rad by Co-60 elements. In some groups of mi ce, treatment with thymopentin was continued for 1 week after irradiat ion. Efficacy of the combination treatment was assessed by evaluation of mortality, as well as by histologic examination of the brain, testi s, bone marrow, heart and spleen. The combination of relatively low do ses of interleukin-1alpha (700 U) with thymopentin yielded a survival which was nearly that observed with interleukin-1alpha (1000 U) given alone (about 100%). The optimal effect was observed in animals treated for 15 days with thymopentin, either in combination or alone. In addi tion, incidence and severity of histological lesions were also lower i n animals with the some treatment schedule. Our results suggest that t he combined treatment thymopentin-interleukin-1alpha prevents radiatio n damage in the mouse.