Association of oxidative stress with the formation of reproductive toxicity from mercury exposure on hermaphrodite nematode Caenorhabditis elegans.

Here we selected HgCl(2) to investigate the mechanism of Hg toxicity on reproduction in hermaphrodite nematodes. Accompanied with decrease of brood size, Hg exposure caused severe deficits in egg number in uterus, egg laying and reproductive structures, including gonad arms and vulva, and formation of protruding phenotype for vulva. Meanwhile, Hg exposure induced severe stress response and oxidative damage in gonad and vulva. Pre-treatment with vitamin E, a potent antioxidant, at the L2-larval stage prevented the oxidative damage and formation of reproductive deficits in Hg exposed nematodes; however, pre-treatment with paraquat, a regent generating superoxide anions, induced more severe reproductive deficits in Hg exposed nematodes. Moreover, Hg exposure increased expression of clk-2 and isp-1 genes, whose mutations decrease ROS production, and decreased expression of mev-1 and gas-1 genes, whose mutations increase ROS production. Thus, oxidative stress may be essential for the induction of reproductive deficits in Hg exposed hermaphrodite nematodes.