PCB-induced environmental stress and the regenerative response in crinoids.

Some persistent and ubiquitous pollutants (PCBs) which can affect the natural environment because of their bio-accumulation in organisms exert their effects by acting as “endocrine disrupters”. In this respect they interact with members of the nuclear receptor family and can induce dramatic effects on gene expression, reproductive competence and development. This paper focuses on the impact of such compounds on natural arm regeneration in crinoids. Since crinoids are benthic and microfilter-feeding animals they are particularly susceptible to the presence of micropollutants in marine sediments. We used the regenerative response of crinoids to monitor and evaluate chronic toxicity by means of tests performed in the laboratory under controlled conditions of known environmental parameters and contamination levels. Exposure to Aroclor 1260, a commercial cocktail of chlorinated congeners, have been performed in static conditions. The concentration of the pollutant has been analysed in both the water and in the whole animal during and at the end of tests. Since the phenomena of tissue renewal involves substantial cell cycle activity and proliferation, the crinoids regeneration bio-test represents an ideal bioindicator of stress at the cellular and molecular level due to persistent pollutants, particularly endocrine disrupters. On the basis of the present results it is quite evident that regenerative response is especially sensitive and that exposure to these types of toxic chemical can induce significant variations in times and modalities of regenerative developmental compared to normal regeneration.