DNA damage in hepatopancreas cells of Haliotis discus hannai induced by P-xylene

Abstract

In order to examine the toxic effects of p-xylene on the hepatopancreas of Haliotis discus hannai, a subchronic toxicity test was carried out for 21 days by setting 4 concentrations (0.5, 1.0, 1.5, and 2.0 mg·L-1) and the control group. DNA damage in hepatopancreas cells of H. discus hannai was analyzed by comet assay. The CASP analysis software was used to analyze the damage indices, including tail rate, tail length, percentage of tail DNA, and olive moment. The results showed that DNA damage in hepatopancreas cells occured in all exposed groups, with different degrees of damage. The DNA damage of hepatopancreas cells was aggravated with the increase of exposure concentration. High concentration of p-xylene could induce apoptosis, showing a certain dose-damage effect. Short-term exposure to medium concentration of p-xylene could cause DNA damage in hepatopancreas cells of H. discus hannai, and the damage degree increased with the extension of exposure time, showing a certain time-damage effect. However, the damage indices of DNA decreased after prolonged exposure, which might be related to the DNA repair mechanism of the cell and the metabolic mechanisms of the detoxification system. In conclusion, p-xylene could induce oxidative damage in hepatopancreas cells of H. discus hannai, resulting in DNA fragmentation. Prolonged exposure to high concentration of p-xylene could lead to apoptosis.