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

Theelevatedconcentrationofhydrogenperoxide(H2O2)duetonaturalandanthropogeniccausesisasignificantbaneto marineandcoastalorganisms,asithasaprolongedhalf-lifeandcaninjectacrosslipidbilayersandinterferewithaquatic redoxprocesses. ThepresentassessmentaimedtodeterminetheacuteeffectofH2O2on larval development of the Mediterranean musselMytilus galloprovincialis and to observethe 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 for48hand(b)adultclamswere exposedto similar concentrations- of this reactive oxygen species (ROS) for 21 days. Incremental H2O2 significantly retardedthegrowthofmussellarvae;thepercentageofmalformedlarvaeincreasedwithincreasingtoxicantconcentration (p <0.01, and r=0.884).H2O2alsoinducedoxidative stress (OS) in clams, indicated by the activation/inactivation of antioxidant enzymes(GST,GPx,andGR)withasignificantriseinlipidperoxidation (LPO)inthedigestivegland 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 confirmedtheir suitability for assessing the effect of H2O2 mediated OS responses in the marine environment.