2-D Gel analysis of protein synthesis in fish hepatocytes exposed to Pb: Development of stress proteins as biomarkers of sublethal chemical exposure : JUDITH GLAVEN, MIRIAM AKKERMAN & BRUCE A. FOWLER. University-wide Program in Toxicology, University of Maryland, Baltimore, Maryland 21201, USA

Abstract

There is a need in aquatic toxicology to develop alternative assays for the assessment of toxicity in fish. In recent years, in vitro assays have been developed for scientific, ethical and economical reasons. In this study, the fish hepatoma cell line PLHC-1 (Hightower & Renfro, 1988) was employed for assessing the cytotoxicity of environmental chemicals, to derive structure activity relationships and to compare in vitro with in vivo toxicity. The cytotoxicity of several important organic compounds, including chloro- and nitrophenols, estrogenic alkylphenols and sulphonic acids, as well as organotin compounds (Brüschweiler et al., 1995), was assessed. Two cytotoxicity assays were performed: inhibition of neutral red uptake (NR) into lysosomes based on cell membrane damage; and the tetrazolium salt reduction (MTT) assay to determine inhibition of mitochondrial succinate dehydrogenase. A high correlation between the two assays was found. Of the various compounds, organotins were most toxic, followed by higher substituted phenols, lower substituted phenols and sulphonic acids. The in vitro cytotoxicity showed a similar trend as the in vivo acute toxicity of fish for organotins and substituted phenols. Furthermore, a positive trend between cytotoxicity and n-octanol-water partition coefficients of the chemicals was found. The results indicate that cytotoxicity assays using this metabolically active hepatoma cell line are a promising tool in the first evaluation and toxicity screening of chemicals prone to contaminate aquatic systems.