| Summary: | The effects of the heavy metals cadmium and copper (50-500 ìM) on the apoptotic events involving changes in mitochondrial membrane potential (ÄØm) and phosphatidylserine (PS) translocation were investigated in the immune cells (celomocytes) of the earthworm Eisenia hortensis. Using the fluorescent probe JC-1, loss of membrane potential due to depolarization was detected in a greater proportion of cases when induced by cadmium compared to copper (58.7 % vs. 37 %) and at a lower concentration (50 ìM vs. 125ìM). With the use of the general caspase inhibitor Z-VAD-fmk, PS translocation detected by annexin V-FITC was found to be caspase-dependent when induced by cadmium at 125-250 ìM but not at 50 ìM or 500 ìM; a high proportion of earthworms (60 %) exhibited inhibitory effects. Additionally, the collapse in membrane potential and PS translocation were found to strongly correlate (r > 0.5) in 89 % of cases when induced by cadmium and copper. Thus, heavy metals appear to induce death in celomocytes of E. hortensis through apoptosis by means of caspase dependent pathways
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