Oxidative stress response to hydrogen peroxide exposure of Mytilus galloprovincialis and Ruditapes philippinarum: Reduced embryogenesis success and altered biochemical response of sentinel marine bivalve species

Abstract

The elevated concentration of hydrogen peroxide (H2O2) due to natural and anthropogenic causes is a significant bane to marine and coastal organisms, as it has a prolonged half-life and can inject across lipid bilayers and interfere with aquatic redox processes. The present assessment aimed to determine the acute effect of H2O2 on larval development of the Mediterranean mussel Mytilus galloprovincialis and to observe the oxidative stress (OS) responses, including genotoxicity and neurotoxicity in the clam Ruditapes philippinarum. Two experiments were performed, in which (a) mussel embryos were exposed to the consecutive dilution (0.0, 0.05, 0.5, 5.0, 50.0 and 500.00 μM) of H2O2 for 48 h and (b) adult clams were exposed to similar concentrations - of this reactive oxygen species (ROS) for 21 days. Incremental H2O2 significantly retarded the growth of mussel larvae; the percentage of malformed larvae increased with increasing toxicant concentration (p < 0.01, and r = 0.884). H2O2 also induced oxidative stress (OS) in clams, indicated by the activation/inactivation of antioxidant enzymes (GST, GPx, and GR) with a significant rise in lipid peroxidation (LPO) in the digestive gland tissues of the clams (p < 0.05). No genotoxicity or neurotoxicity on R. philippinarum were evident after chronic exposure. The battery of responses (organismal and cellular parameters) showed embryotoxicity and sublethal effects on bivalves, which confirmed their suitability for assessing the effect of H2O2 mediated OS responses in the marine environment.