Exposure to polychlorinated biphenyls (PCBs) affects the histology and antioxidant capability of the clam Cyclina sinensis

Abstract

Polychlorinated biphenyls (PCBs) are environmentally persistent and highly toxic organochlorine compounds that may cause toxic effects on aquatic animals. In this study we assess the toxic effect of PCBs on a bivalve used in aquaculture, the clam Cyclina sinensis. To this end, individuals of C. sinensis were exposed for 72 h at two PCB concentrations (1 ng/L and 10 ng/L) and control (absence of PCBs). At the end of the exposure, the hemolymph, hepatopancreas, and gills samples of C. sinensis were harvested for analysis of the enzyme activity and histology. The results showed that acute PCBs exposure decreased the survival rate of C. sinensis compared to the control. Acute PCBs exposure up-regulated the enzymatic activity of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) and the content of malondialdehyde (MDA) in the hemolymph of C. sinensis, while down-regulated the non-specific enzymatic activity of alkaline phosphatase (AKP). For the hepatopancreas, 1 ng/L PCBs exposure up-regulated the enzymatic activity of SOD while down-regulated the enzymatic activity of CAT of C. sinensis. In the gill, the enzymatic activity of CAT decreased significantly and the MDA content increased of C. sinensis after 10 ng/L PCBs exposure. Moreover, histological observations showed that acute exposure to PCBs caused loss of gill filaments and lateral cilia and shortening of their length, in the studied organism. The present study will provide valuable reference data for marine shellfish aquaculture and toxicology research.

Polychlorinated Biphenyl (PCB) in Environment: Contamination, Toxicity, and Carcinogenicity

“…Symptoms reported in the workplace include slight irritation to skin and eyes at airborne levels above 0.1 mg per cubic meter with intolerable irritation occurring above 10 mg per cubic meter (3). In a comparison study in animals, (13) showed that acute PCB exposure decreased the survival rate of Cyclina sinensis mussels compared to controls. Acute PCB exposure regulates the enzymatic activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) and malondialdehyde (MDA) content in C. sinensis hemolymph, while decreasing nonspecific enzymatic regulation of alkaline phosphatase (AKP).…”

Marine Animal Co-Products—How Improving Their Use as Rich Sources of Health-Promoting Lipids Can Foster Sustainability

“…Contaminant accumulation has been reported in crustacean hepatopancreas [334][335][336] and in the skin, viscera, bones, and scales of fish [337][338][339][340][341]. Mollusks also accumulate toxicants [342][343][344][345], with the digestive glands and gills of hard-shelled animals representing preferential accumulation sites [346][347][348]. The presence of marine biotoxins may represent a very concrete challenge for the use of marine animal co-products.…”