LIPID-PEROXIDATION IN MICROSOMES OF MURINE BONE-MARROW AFTER LOW-DOSEGAMMA-IRRADIATION

The principal aim of the study was to investigate the effect of low-do se gamma-irradiation on lipid peroxidation (LPO) in murine bone marrow . To this end, the degree of LPO in suspensions of microsomes of murin e bone marrow cells (BMC) was determined in terms of malondialdehyde ( MDA) formation after whole-body or in vitro exposure to various doses of gamma-radiation. These effects were compared to some extent with si milar effects in liver and spleen preparations. As to the effect of ga mma-irradiation on LPO in BMC, the response depends on the dose level and on whether whole-body or in vitro exposures are involved. Whole-bo dy irradiation did not result in an increase in LPO in BMC microsomes, even at such high doses as 15 Gy, although hepatic microsomes showed a marked increase. In contrast, in vitro irradiation of BMC microsomes with 0.1, 10 and 50 Gy brought about an increase in LPO. This increas e was already significant (P < 0.05) at 0.1 Gy following a post-irradi ation incubation and substantial at 50 Gy, even without subsequent inc ubation. The results show that low doses of gamma-irradiation are able to induce an elevation of LPO in murine BMC microsomes, but only afte r in vitro irradiation. In the case of whole-body irradiation cellular radical scavengers and other metabolic reactions may prevent a measur able increase in LPO. This is partly illustrated by the case of vitami n-E deficiency, where a substantial increase in LPO in BMC microsomes is observed even without gamma-irradiation in comparison with euvitami notic mice because normally occurring radicals are not scavenged suffi ciently.