Transient inhibition of cyp1a gene transcription and EROD activity by musk xylene exposure in two fish cell lines PLHC-1 and RTG-2

摘要

Musk xylene (MX) is one of the most used synthetic nitromusk fragrance in personal care products. The high release in the aquatic environment together with the evidence of bioaccumulation in aquatic organisms suggest that this chemical could be an actual concern for toxicological consequences. Nevertheless no much data are available on cellular pathways and mechanisms of toxicity in aquatic organisms. The aim of the present study was to investigate the capability of MX to interfere with phase I of biotransformation by looking at cyp1a gene transcription and related enzyme activity in two fish cell lines as PLHC-1 and RTG-2. A dose-dependent (2, 4, 20 μM) and time-dependent (6, 12 and 24 h) exposure experiments have been performed testing MX alone and combined with a known CYP1A inducer as B(a)P. A transient inhibition of cyp1a gene transcription was observed after 6 h in both cell lines which seems to recover dose-dependently after 24 in RTG-2 and less markedly in PLHC-1. EROD activity did not show clear effect after 6 h while resulted significantly inhibited in both cell lines after 24 h. A common pathway of inhibition at gene level could be thus hypothesised in both cell lines after 6 h of exposure confirmed by EROD activity inhibition at 24 h. The potential involvement of MX metabolites in cyp1a gene recovery after 24 h of exposure could be hypothesized. Results of the time dependent experiment also suggest a different pathway of gene regulation for MX compared to B(a)P.