Dietary cadmium (Cd) reduces hemocyte level by induction of apoptosis in Drosophila melanogaster

Abstract

Drosophila melanogaster larvae ensure continuous proliferation and differentiation of hemocytes to maintain a fixed range of different blood cell types during its various stages of development. Variation in this number is often an indicator of animal well-being, its genotype or an effect of environmental perturbation, including exposure to heavy metals. The present study investigates the effect of Cd on larval hemocytes. Embryos were allowed to grow in metal media till third instar larvae and finally circulating hemocyte were collected. The number of major hemocytes, plasmatocytes and crystal cells was determined to be lowered in Cd exposed animals. Our results also showed modulation of antioxidant biology of Cd exposed hemocytes by changing the major antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) activity, and decreasing reduced glutathione (GSH) levels in hemocytes suspended in the hemolymph. Acridine orange (AO) staining further revealed induction of apoptosis in hemocytes of metal treated larvae. Our results suggest a negative impact of Cd exposure on the hemocytes of the Drosophila larvae culminating in their lowered count by induction of apoptosis.