Hydroxylated-Benz[a]anthracenes Induce Two Apoptosis-Related Gene Expressions in the Liver of the Nibbler Fish .

Polycyclic aromatic hydrocarbons (PAHs) are known to have toxic effects on fish. In this study, we examined the effects of benz[a]anthracene (BaA), a type of PAH, on fish liver metabolism. Nibbler fish () were intraperitoneally injected with BaA (10 ng/g body weight) four times over a 10-day period. BaA significantly decreased known bone metabolism-related plasma factors such as calcium and inorganic phosphorus. Moreover, significant reductions were observed in the plasma levels of known liver metabolism-related factors, including ferrous ions, total bile acids, total bilirubin, free bilirubin, aspartate aminotransferase, and alkaline phosphatase. Interestingly, mono-hydroxylated metabolites of BaA, such as 3 hydroxylbenz[a]anthracene (3-OHBaA), were detected in the bile of BaA-injected nibbler fish. This hydroxylated form of BaA was found in its free form, rather than conjugated with glucuronic acid or sulfuric acid. Due to the lack of whole-genome sequence data for the nibbler fish, two nibbler fish-specific apoptosis-related factors (TNF receptor superfamily member 1A: and TNF superfamily member 10: ) were isolated by De novo RNA sequencing. In a liver tissue culture, 3-OHBaA (10 M) significantly upregulated the expression of and in the liver. These results provide the first evidence that 3-OHBaA metabolites exhibit toxic effects on the liver in teleost.