P-gp expression levels in the erythrocytes of brown trout: a new tool for aquatic sentinel biomarker development.

CONTEXT: P-glycoprotein (P-gp) is a ubiquitous membrane detoxification pump involved in cellular defence against xenobiotics. Blood is a hub for the trade and transport of physiological molecules and xenobiotics. Our recent studies have highlighted the expression of a 140-kDa P-gp in brown trout erythrocytes in primary cell culture and its dose-dependent response to Benzo[a]pyrene pollutant.

OBJECTIVE: The purpose of this study was focused on using P-gp expression in brown trout erythrocytes as a biomarker for detecting the degree of river pollution.

METHODS: abcb1 gene and P-gp expression level were analysed by reverse transcriptase-PCR and Western blot, in the erythrocytes of brown trouts. The latter were collected in upstream and downstream of four rivers in which 17 polycyclic aromatic hydrocarbons and 348 varieties of pesticides micro-residues were analysed by liquid chromatography and mass spectrometry.

RESULTS: The abcb1 gene and the 140-kDa P-gp were not expressed in trout erythrocytes from uncontaminated river. In contrast, they are clearly expressed in contaminated rivers, in correlation with the river pollution degree and the nature of the pollutants.

CONCLUSIONS: This biological tool may offer considerable advantages since it provides an effective response to the increasing need for an early biomarker.