Histological and immunocytochemical study on the detoxification of cadmium chloride in Anadara notabilis (Röding 1798) (Bivalvia, Arcidae)

Marine organisms are subjected to pathogens and xenobiotics in their natural ecosystem. The objective of this study was to test the role of hemocytes in Anadara notabilis subjected to cadmium chloride pollution. The clams were collected from the Mediterranean Sea off Alexandria, Egypt, in summer and winter 2019 for morphological and immunocytotoxic studies. Sodium Dodecyl sulfate polyacrylamide gel electrophoresis was carried out to separate the proteins of hemolymph lysate. Immunodetection was performed with anti-inducible and anti-endothelial nitric oxide synthesis and anti-p105 antibody. Nitric oxide production in hemocytes was tested. Nucleic acids were extracted and quantified. Clams subjected to cadmium chloride pollution (100 µg/L, 250 µg/L and 500 µg/L) showed a multifocal inflammatory reaction in the columnar epithelia and the connective tissue with mantle retraction in an active encapsulation. During summer hemocytes incubated with interleukin-2 released more nitric oxide than control cells while the use of the protein kinase C inhibitor caused a slight increase in the nitric oxide synthesis compared to hemocytes incubated in interleukin-2. The use of monoclonal antibodies in hemocytes lysate incubated with the different inducers revealed the presence of 140 and 145 kDa bands in both control and treated clams during summer and winter. The proportion of SH hemocytes (spreading cells with phagocytic activities) exceeded that of RH cells (round cells with non-phagocytic activities) in summer and winter. During winter, the DNA fragments appeared characteristic of apoptosis. This study concludes that interleukin-2 causes notable increases in NO production irrespective of season. During summer hemocytes produce an amount of NO double than those observed during winter.