Cytotoxicity induced by abamectin exposure in haemocytes of Chinese mitten crab, Eriocheir sinensis

Abamectin is widely utilized in both agricultural and aquaculture areas in China for pest control. However, information about toxic effects of abamectin on non-target aquatic organisms is still incomplete. The Chinese mitten crab, Erocheir sinensis has been extensively bred in the rice-crab co-culture system for years, resulting in the frequent exposure to pesticides including abamectin. In the present study, a primary haemocyte culture model was established to investigate the immune response under exposure of abamectin. The results showed that medium osmolarity ranging from 360 to 480 mOsM/Kg was optimal for primary haemocyte culture from E. sinensis. Abamectin could induce significant decrease of cell viability, inhibition of phagocytic activity, as well as decline of Acid Phosphatase (ACP) and Alkaline Phosphatase (AKP) activities. All parameters decreased in time- and dose- dependent manners throughout the experiment, indicating the remarkable immunosuppression of abamectin on E. sinensis and also the sensitivity of the cytotoxicology model of haemocytes in vitro under abamectin exposure. In addition, a dose dependent increase of intracellular Reactive Oxygen Species (ROS) was found after 6 h exposure. It revealed that excessive generation of ROS may a main reason to the degradation of cell viability, and moreover, the decrease in immune function.