PCB exposure and regeneration in crinoids (Echinodermata)

Echinoderm regeneration provides a convenient and tractable test to monitor the effects of persistent micropollutants on the developmental physiology of marine animals. Regeneration involves crucial and sensitive biological processes (cell proliferation, morphogenesis, differentiation, tissue renewal) that make it an ideal tool to assess micropollutants at the tissue and cellular level. Our results provide evidence that the regenerative response in the crinoid Antedon mediterranea is especially sensitive to PCBs and that exposure to these chemicals induces significant variations in timing and modality of arm regeneration. Prolonged exposure to low concentrations of Aroclor®1260 (14 ng l–1 of total PCBs), typical of moderately polluted coastal zones, results in abnormal arm growth in terms of both gross morphology and microscopic anatomy. In terms of tissue/cellular aspects the main modifications are: accelerated growth of the regenerate; massive cell migration/proliferation; hypertrophic development of the coelomic canals; and, extensive rearrangement of differentiated tissues of the stump. The anomalies observed in the developmental regenerative processes appear to be compatible with a pattern of pseudo-endocrine activities.