Effects of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans on phagocytic response of Eisenia andrei coelomocytes

Abstract

The immunotoxicological effects of polychlorinated dibenzo-p-dioxins/dibenzofurans (PCDDs/Fs) mixtures on <em>Eisenia andrei </em>earthworms have never been studied. In this work we investigated these effects both for <em>in vitro </em>and <em>in vivo</em> exposure, using the viability and the phagocytic activity of coelomocytes as immunological biomarkers and the flow cytometry was used for analysis. The <em>in vitro </em>exposure revealed a cytotoxic effect of PCDD/Fs mixture (C2) containing 50&yen;10-3 ng/mL of 2, 3, 7, 8-TCDD and an induction of the phagocytic capacity at the mixture (C1) containing 25&yen;10-3 ng/mL of 2, 3, 7, 8-TCDD. In the <em>in vivo </em>filter paper exposure, the immunocompetence of earthworms was assessed after 3 h-exposure to mixtures of PCDD/Fs at the levels of C1, C2, C3 and C4 containing about; 0.05, 0.3, 0.5 and 0.83 ng of 2, 3, 7, 8-TCDD/cm&sup2;, respectively. Morphological observations showed an excessive secretion of mucus and body surface lesions in worms exposed to higher concentrations (C3 and C4), which revealed that these organisms were affected by PCDD/Fs either through skin and/or by feeding. The levels of the extruded cell yield decreased significantly at all the concentrations tested. However, the cell viability was shown to be unaffected by PCDD/Fs concentrations. It was also shown, that exposure to the highest PCDD/Fs concentrations; C2, C3 and C4 inhibited both phagocytic activity and efficiency.