Abstract
Model organisms such as Drosophila m. have made it possible to study the effects of different environmental oxygen conditions on lifespan and oxidative stress. However, many studies have often yielded controversial results usually assigned to variations in Drosophila genetic background and differences in study design. In this study, we compared longevity and ROS levels in young, unmated males of three laboratory “wild-type” lines (Canton-S, Oregon-R and Berlin-K) and one mutant line (Sod1n1), under both normoxic and hypoxic (2% oxygen - 24h) conditions. Lifespan was used to detect the effects of hypoxic treatment and differences were analysed by means of Kaplan-Meier survival curves. EPR spectroscopy was used to measure ROS levels and analysis of variance was used to estimate the effects of hypoxic treatment and to assess ROS differences between strains. As expected, in normoxia Sod1n1 are the shortest-lived, while the wild-type strains, despite a longer lifespan, show some differences, with the Canton-S line displaying the lowest mortality rate. After hypoxic stress these variances are amplified, with Berlin-K flies showing the highest mortality rate and most evident reduction of lifespan. Moreover, our analysis highlighted differential effects of hypoxia on redox balance/unbalance. Canton-S flies had the lowest increase of ROS level compared to all the other strains, confirming it to be the less sensitive to hypoxic stress. Sod1n1 flies displayed the highest ROS levels in normoxia and after hypoxia. These results should be used to standardize future Drosophila research models designed to investigate pathways that may be involved in lifespan and/or ROS, as well as comparative studies on specific mutant strains.