Low dose radiation induced hormesis and its mechanism of free radicals

Abstract

Objective To investigate whether supematant (the stimulating fluid) centrifuged from myeloid cells suspension after low dose radiation in vitro can produce hormesis on normal or radiation damage cells. The mechanism of free radical was probed. Methods Mouse myeloid cell suspension was irradiated respectively by 0, 2 and 5 Gy, and cultured in vitro. MTT method was used to measure reproductive activity of cells. Meanwhile, Cytochrome C reduction method was used to determine concentration of O2-. Lastly, concentration of O2- was decreased or increased by adding DPI or PMA, and effect of such changes on the stimulating was observed. Results Co-cultured with the stimulating fluid, reproductive activity of myeloid cells after large dose radiation or normal myeloid cells were enhanced. Decreasing concentration of O2- may degrade proliferation of cells after radiation damage; while increasing it may lead to opposite result. Conclusions The stimulating fluid can enhance proliferation of myeloid cells after radiation damage and also normal ones. The mechanism of above-mentioned phenomena might be related with changes of O2- concentration. Key words: Low dose radiation; Hormesis; Free radicals