Insights into mechanism of DNA damage and repair-apoptosis in digestive gland of female scallop Chlamys farreri under benzo[a]pyrene exposure during reproductive stage.

As one of the most carcinogenic persistent organic pollutants (POPs), benzo[a]pyrene (B [a]P) brings high toxicity to marine bivalves. Digestive gland is the most important metabolism-related organ of aquatic animals. This study conducted the digestive gland transcriptome of Chlamys farreri under B[a]P treatment at reproductive stages. And the reproductive-stage dependence metabolism-DNA repair-apoptosis process of scallops under 0, 0.04, 0.4 and 4 μg/L B[a]P was studied by qRT-PCR. The results demonstrated that the detoxification metabolism was disturbed after ovulation except for CYP3A4. In antioxidant system, antioxidant enzyme CAT and GPX, and GGT1 (one of the non-enzymatic antioxidants synthesis gene) continuously served the function of antioxidant defense. Three types of DNA repair were activated under B[a]P stress, however, DNA strand breaks were still serious. B[a]P exposure weakened death receptor pathway as well as enhanced mitochondrial pathway, surprisingly suppressing apoptosis in scallops. In addition, ten indicators were screened by Spearman correlation analysis. This study will provide sound theoretical basis for bivalve toxicology and contribute to the biomonitoring of marine POPs pollution.