title: Effects of the model PAH phenanthrene on immune function and oxidative stress in the haemolymph of the temperate scallop Pecten maximus.
abstract: Phenanthrene, a major component of crude oil, is one of the most abundant PAHs in aquatic ecosystems, and is readily bioavailable and toxic to a range of marine invertebrates. Within bivalves, the haemolymph acts as a transfer medium for these pollutants and their metabolic products, leaving haemocytes susceptible to deleterious effects. Using a suite of biological endpoints, this study determined the sublethal (7-d exposure to 50, 100 and 200microgL(-1)) effects of phenanthrene on several oxidative stress and immunological parameters in the haemolymph of the commercially-important scallop Pecten maximus. Phenanthrene exposure (200microgL(-1)) resulted in immune modulation with significant reductions in cell membrane stability (P<0.05) and phagocytosis (P<0.05), and a significant increase in the number of total haemocytes (P<0.05). Oxidative stress was also observed with a significant decrease in total glutathione (P<0.05) and significantly increased levels of lipid peroxidation in the haemolymph (P<0.05). Changes in the cellular and biochemical endpoints observed in this study illustrate their potential use in assessing the subtle effects of contaminant exposure. Whilst previous reports have suggested a link between free radical generation and immune suppression in vertebrates, this is the first instance where oxidative stress and immune function have been measured together in the haemolymph of a bivalve mollusc, demonstrating a possible link between PAH-induced oxidative stress and the subsequent inhibition in haemocyte immune function.
authors.affiliation: Ecotoxicology and Stress Biology Research Centre, University of Plymouth, Drake Circus, Devon, UK. marie.hannam@plymouth.ac.uk
authors.forename: Marie L
authors.initials: ML
authors.lastname: Hannam
authors.forename: Shaw D
authors.initials: SD
authors.lastname: Bamber
authors.forename: Tamara S
authors.initials: TS
authors.lastname: Galloway
authors.forename: A
authors.initials: A
authors.lastname: John Moody
authors.forename: Malcolm B
authors.initials: MB
authors.lastname: Jones
mesh_terms: D000818:Animals; D005978:Glutathione / Q000378:metabolism; D006458:Hemolymph / Q000187:drug effects / Q000276:immunology*; D015227:Lipid Peroxidation; D008956:Models, Chemical; D018384:Oxidative Stress; D049910:Pecten / Q000187:drug effects*; D010587:Phagocytosis; D010616:Phenanthrenes / Q000633:toxicity*; D013997:Time Factors; D014874:Water Pollutants, Chemical / Q000633:toxicity*
chemical_list: D010616:Phenanthrenes; D014874:Water Pollutants, Chemical; C031181:phenanthrene; D005978:Glutathione