Antioxidants Boost Male Fertility: The Role of Reactive Oxygen Species (ROS) in Modulating Fertility and Sperm Viability in Drosophila melanogaster

Abstract

Reactive oxygen species (ROS) in large amounts have been shown to cause peroxidative damage to tissues. ROS production is heightened in stressful environments, such as after exposure to toxins. Antioxidants have been previously found to reduce lifespan-related, peroxidative damage, inflicted by reactive oxygen species in the common fruit fly (D. melanogaster). Our study analyzes the effects of antioxidants in reducing the damaging effects of reactive oxygen species to rescue pre and post-copulatory reproductive efforts in Drosophila melanogaster. We hypothesized that if male fruit flies were fed antioxidant-enriched diets prior to a reactive oxygen species assault, then the antioxidants would quench the reactive oxygen species. This would then reduce the lipid peroxidation damage to male sperm, resulting in increased pre-copula and post-copula reproductive efforts. Two groups of fruit fly food were each infused with antioxidants, lipoic acid (2.15mM) or melatonin (0.43mM) in 75%ethanol. 75% ethanol solution was used as a control. Males from all treatments were then fed an herbicide, paraquat, to shock their immune systems and increase ROS production. All males were then mated to virgin females and copula behavior, sperm viability and male fertility were assessed. Our results showed significant differences between treatments in sperm viability and number of offspring sired. However, there were no significant differences in mating probability or copula duration (both related to pre-copula sexual selection). These results draw light on the important interplay of ROS and antioxidants in the maintenance of reproductive health especially during stress.