Low-dose ionizing radiation increases the lifespan of Drosophila melanogaster under oxidative stress conditions through AKT/SOD regulation

To investigate the biological effects of low-dose ionizing radiation (LDIR) on living organisms, we analyzed the effects of LDIR of 0.05 Gy and its mechanism on the Drosophila melanogaster, which is an ideal model organism for aging studies due to its short lifespan and conserved molecular pathways. The embryos of Drosophila melanogaster were irradiated and we analyzed the effects of LDIR treatment on the lifespan of Drosophila melanogaster. To investigate the effects of LDIR under oxidative stress conditions, because oxidative stress is a major cause of aging, reactive oxygen species (ROS) levels and the oxidative stress susceptibility of flies under hydrogen peroxide (H2O2)-induced oxidative stress conditions were evaluated at early post-irradiation time points. We next elucidated the effects of LDIR on the molecular mechanisms of lifespan extension. LDIR extended the lifespan, but did not alter developmental rates. In addition, the locomotive deterioration of aged flies was rescued by exposure to a 0.05 Gy dose of γ-irradiation. LDIR increased the survival rates and locomotive ability under oxidative stress conditions and decreased mRNA levels of the pro-apoptotic factors, grim and reaper. Moreover, 0.05 Gy of LDIR decreased ROS accumulation and increased superoxide dismutase (SOD) activity in flies exposed to H2O2. Also, LDIR activated AKT pathway in H2O2-treated flies and inhibition of AKT activity suppressed the effects of LDIR. LDIR of 0.05 Gy extends the lifespan and survival rates under H2O2-induced oxidative stress conditions by controlling ROS levels via AKT activation.