Toxic dinoflagellate Alexandrium tamarense induces oxidative stress and apoptosis in hepatopancreas of shrimp (Fenneropenaeus chinensis)

This study investigated the inductive effect of Alexandrium tamarense, a toxic dinoflagellate producing paralytic shellfish poison, on oxidative stress and apoptosis in hepatopancreas of Chinese shrimp, Fenneropenaeus chinensis. The individuals of F. chinensis were exposed to 200 and 1000 cells mL^‑1 of A. tamarense with their superoxide dismutase (SOD), glutathione S-transferase (GST) activities, malonyldialdehyde (MDA) concentration, and caspase gene (FcCasp) expression in hepatopancreas determined at 12, 24, 48, 72 and 96 h. In addition, apoptosis in hepatopancreas of F. chinensis at 96 h after exposure was determined through terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay. The hepatopancreatic SOD and GST activities of F. chinensis exposed to 1000 cells mL^‑1 of A. tamarense showed a bell-shaped response to exposure time. The hepatopancreatic MDA concentration of F. chinensis exposed to 1000 cells mL^‑1 of A. tamarense increased gradually from 48 to 96 h, and such a trend corresponded to the decrease of GST activity. The hepatopancreatic FcCasp transcript abundance of F. chinensis exposed to 1000 cells mL^‑1 of A. tamarense was positively and linearly correlated to MDA concentration. Results of TUNEL assay showed that exposure to 1000 cells mL^‑1 of A. tamarense induced apoptosis in the hepatopancreas of F. chinensis. Our study revealed that A. tamarense exposure influenced the antioxidative status of F. chinensis and caused lipid peroxidation and apoptosis in the hepatopancreas of shrimp.