Effects on CYP1A of the polycyclic musk tonalide (AHTN) in single and co-exposure with benzo(a)pyrene and 3,3′-4,4′,5-pentachlorobiphenyl in the PLHC-1 fish cell line

Abstract

The aim of this study was to investigate the interaction of a common polycyclic musk fragrance, namely tonalide (AHTN), with the detoxification gene family CYP1A, by looking at both gene transcription (cyp1a) and enzyme activity (7-ethoxyresorufin-O-deethylase; EROD) in the PLHC-1 fish cell line. Time-dependent (6 and 24 h) exposure experiments with three doses of AHTN (1 nM, 10 nM and 2 μM) were performed. Co-exposure with known CYP1A inducers such as benzo[a]pyrene (B[a]P) and 3,3′-4,4′,5-pentachlorobiphenyl (PCB 126) was also investigated. A slight induction of cyp1a gene transcription was observed after 6 h, but not at 24 h. At 6 h, 40–45% of reduction of cyp1a transcription was observed in co-exposure with B[a]P and PCB 126 compared with single inducers. Complete recovery was observed after 24 h. No effect on EROD activity by AHTN was observed in either single exposure and co-exposure. AHTN seemed not to affect CYP1A at the gene or enzyme level, but in co-exposure with inducers ATHN seems able to reduce detoxification capability within a short time.

Keywords:

• tonalide
• CYP1A
• EROD
• detoxification
• co-exposure
• PLHC-1

Acknowledgements

The study was financed by the Italian Ministry for Universities and Research (MIUR) based on PRIN project 2007J23NNX_001 2007. The authors are grateful to Roko Zaja and Jovica Loncar from the Ruder Boskovic Institute for setting up the PLHC-1 analysis and to Tvrtko Smital for great advices and support.