Characterization of cadmium transport in hepatopancreatic cells of a mangrove crab Ucides cordatus: The role of calcium

Cadmium is a toxic metal, present in batteries and discarded in estuaries and mangrove habitats. Apart from that, it is a non-essential metal that causes toxic effects in many organisms. Cadmium accumulates in gills and hepatopancreas of crustaceans and its route into the cell is unknown. It is possible that occurs by calcium channels or calcium transporters. The objective of this study was to characterize the transport of cadmium and the role of calcium in different cell types from hepatopancreas of the mangrove crab Ucides cordatus. For this, the hepatopancreas was dissociated by magnetic stirring and after that separated by a sucrose gradient. Then, the cells were labeled with FluoZin-3 AM and different CdCl2 concentrations were added together with a variety of inhibitors. The results showed that Cd2+ transport occurs differently in each cell type from hepatopancreas and is partially explained by the function the cells perform in this organ. Embryonic (E) and Resorptive (R) cells transported more Cd2+ compared to Fibrillar (F) and Blister (B) cells. R cells responded to Ca2+ channel inhibitors and intracellular Ca2+ manipulations positively, as the other cell types and in a stronger way. B cells were the least responsive to Ca2+ channel inhibitors and, unlike the other cells, showed a competition of Cd2+ with intracellular Ca2+ manipulations. The results indicate that Ca2+ affects the transport of Cd2+ in hepatopancreatic cells of Ucides cordatus and uses Ca2+ channels to enter these cells. In addition, information about Ca concentration could be used as a mitigating factor for Cd accumulation in crabs' hepatopancreas.