Histopathological progression of hemic neoplasms in the tropical crab Paratelphusa hydrodromous (Herbst) treated with sublethal cadmium chloride

Abstract

Tropical crab Paratelphusa hydrodromous were exposed in the laboratory to five sublethal cadmium chloride concentrations (0.02, 0.05, 0.25 and 0.50μM/L) for 30 days to evaluate the cellular inflammatory and chronic pathologic responses. The most frequent pathologic responses of hepatopancreas exposed to 0.25–0.50 μM CdCl₂/L were atrophy of R-cells and the development of granulomatous reaction consisting of granulocytes and monomorphic basophilic cells. Coagulative necrosis was evident in the young oocytes at 0.05 μM CdCl₂/L which was accompanied by the increased vitellophagia of follicle cells. Thirty-day exposure to 0.25–0.50 μM CdCl₂/L shortened the reproductive life span of the crabs by inducing spontaneous atresia and granulocytosis. Eosinophilic granulocytes, the most numerous cell type found in the necrotic centers, phagocytosed the masses of cellular debris and yolk from cadmium-induced atretic oocytes. The widespread proliferation of basophilic cells related to hyalinocyte with high nucleocytoplasmic ratio would suggest the development of hemic neoplasia. Heavy granulocytic infiltration was the typical cellular inflammatory response during chronic pathological conditions.