Toxicopathic hepatic lesions in subadult English sole (Pleuronectes vetulus) from Puget Sound, Washington, USA: Relationships with other biomarkers of contaminant exposure

Liver neoplasms are rarely detected in young wild fish. Therefore, other lesions occurring early in the histogenesis of hepatic neoplasia need to be considered as biomarkers of chemical contaminant exposure effects in monitoring studies, especially where adult fish are nor available. Moreover, exposure effects may be more reliably assessed in younger fish that have not yet migrated extensively. Accordingly, livers of subadult English sole were histologically examined from nine sires in Puget Sound, WA and the same fish were assessed for contaminant exposure by measurement of fluorescent aromatic compounds (FACs) in bile, hepatic levels of polychlorinated biphenyls (PCBs) and cytochrome P4501A (CYP1A) as catalytic activity of aryl hydrocarbon hydroxylase (AHH), and hydrophobic DNA adducts in liver by P-32-postlabelling. Although neoplasms were rare, higher prevalences of preneoplastic, regenerative, and unique degenerative/ necrotic lesions were detected in sole from contaminated sites. Prevalences of these early histopathologic biomarkers were significantly higher at the more contaminated sites, and concentration of mean biliary FACs at each capture site was a significant risk factor for most lesions, as determined by stepwise logistic regression. By this statistical method, we also demonstrated that several measures of bioaccumulation or biochemical response to contaminants were significant and near-significant risk factors for prevalences of most hepatic lesion categories. For example, mean hepatic AHH activity was a significant risk factor for prevalence of all lesion types, except neoplasms; hepatic PCB and xenobiotic-DNA adduct concentrations were significant risk factors for the most frequently detected lesion category, hepatocellular nuclear pleomorphism/megalocytic hepatosis, and the inclusive category 'any early toxicopathic lesion'. These findings further support the utility of certain non-neoplastic liver lesions as early indicators of biological damage in subadult as well as adult fish exposed to xenobiotics in the marine environment. Published by Elsevier Science Ltd.