Cytochrome P450 system expression and DNA adduct formation in the liver of Zacco platypus following waterborne Benzo(a)pyrene exposure: implications for biomarker determination

Abstract

Benzo(a)pyrene (BaP) is a polycyclic aromatic hydrocarbon that causes mutations and tumor formation. Zacco platypus is a sentinel species that is suitable for monitoring aquatic environments. We studied cytochrome P450 system (CYP system) expression and DNA adduct formation in the liver of Z. platypus following waterborne exposure to BaP. The results showed both dose and time dependency. The significant induction levels of CYP system mRNA and protein reached maximums at 2 days and 14 days, respectively, and hepatosomatic index was maximally induced at 4 days during 14 days BaP exposure. DNA adduct formation was significantly induced compared to corresponding controls (t-test, p < 0.01) after 4 days of exposure in 100 μg/L BaP. These results indicate that the only use of mRNA expression level of CYP system as a biomarker make us underestimate prolonged toxicity (4-14 days) of BaP and the only use of protein expression level of CYP system make us underestimate acute toxicity (1-2 days) of BaP. Therefore, we suggests that a combinational use of the mRNA expression level and protein expression level of CYP system, hepatosomatic index is a useful biomarker in risk assessment of waterborne BaP exposure. In addition, DNA adduct formation was a useful biomarker in risk assessment of waterborne BaP exposure at 4 days. CYP1A was a more sensitive biomarker than CYP reductase for BaP exposure when considering both the mRNA and protein level. Furthermore, our results show that Z. platypus is a useful species for assessing the risk of waterborne BaP exposure.

Effects of phenol on metabolic activities and transcription profiles of cytochrome P450 enzymes inChironomus kiinensislarvae

“…The regulation of CYP enzyme activity may play a central role in the adaptation of aquatic and/or marine animals to environmental pollutants. In Zacco platypus , Lee et al (2014) reported significant inductions of CYP system mRNA and protein, as well as increases in the hepatosomatic index, which reached maximum levels at 2, 14 and 4 days, respectively, during a 14-day B a P exposure; they suggested that a combination of the CYP system mRNA and protein expression levels, and the hepatosomatic index, would provide a useful biomarker in risk assessments of waterborne B a P exposure.…”

Significance of adverse outcome pathways in biomarker-based environmental risk assessment in aquatic organisms

“…In a recent study, BaP induced both CYP1A mRNA and protein expressions in liver and gills of four well known model species (freshwater minnow Zacco platypus, zebrafish Danio rerio, Japanese medaka Oryzias latipes, and common carp Cyprinus carpio) (Lee et al, 2015). Moreover, a positive correlation has been observed between CYP1A protein levels and DNA adduct formation in the teleost fish Z. platypus upon exposure to BaP (Lee et al, 2012). In BaP-exposed killifish (Fundulus grandis and F. similus), a dose-dependent increase in the formation of DNA adducts has been reported, along with significant modulation of CYP1A genes (Willett et al, 1995).…”

“…2). The MIE of BaP exposure is the binding of BaP to the AhR (Hahn, 2002;Lin et al, 2003b;Wang et al, 2010), leading to AhR activation and CYP1A expression in teleost fish (Haasch et al, 1993;Levine and Oris, 1999;Hahn, 2002;Bo et al, 2010;Wang et al, 2010;Lee et al, 2012). In the red sea bream Pagrus major, expression of Pm-CYP1A1 and Pm-AhR2 is induced simultaneously in a time-dependent and dose-dependent manner (Bo et al, 2010).…”

Multiwall Carbon Nanotube-Induced Apoptosis and Antioxidant Gene Expression in the Gills, Liver, and Intestine ofOryzias latipes

“…Oryzias latipes has been used widely as an experimental fish for monitoring pollutants for over a century [2]. Fish liver is a major detoxification organ and the gills and intestine are useful monitor organs that reflect the health of aquatic organisms and have been used as target organs in aquatic toxicity studies [3–5]. …”