Effects of Benzo (a) Pyrene on Ethoxyresorufin-O-deethylase (EROD) Activity and Genomic Damage in Java Medaka (Oryzias Javanicus)

Benzo[a] pyrene (BaP) is a high molecular weight polycyclic aromatic hydrocarbon (PAH) that have high carcinogenic effects. So, the aim of this study was to assess the effects of benzo [a] pyrene (BaP) on liver EROD enzyme activity induction and liver DNA breakage in Java Medaka.
twenty three Java Medaka were transferred to 10 L glass aquarium and exposed to benzo [a] pyrene concentrations of 0.5 µg/L (Low concentration), 1.5 µg/L (median concentration), 5 µg/L and 0 µg/L (DMSO solvent control), with semi-static renewal technique during 7 days. Fish liver biopsy was performed in seventh day and a part of the samples was immediately homogenized and were used to measure EROD enzyme activity. Another part of the liver samples were transferred to -20 °C to use for DNA integrity assay. Data were analyzed by using ANOVA and Duncan tests. The p value ≤ 0.05 was considered as a level of statistical significance.
A significant increase in EROD anzyme activity was observed between the experimental treatments compared to the control group. Although the fishes that exposed to the highest concentration (5 micrograms per liter) of Benzo[a] pyrene had higher DNA breakage. Nevertheless, there was no significant difference between the treatment groups compared to the control group.
benzo[a]pyrene combination increased hepatic EROD activity, the enzyme in the initial phase of PAH detoxification, in Java Medaka. However, it seems that Java Medaka fish have a DNA repair and preventive mechanisms from liver DNA breakage.