Echinoderm regenerative response as a sensitive ecotoxicological test for the exposure to endocrine disrupters: effects of p,p′DDE and CPA on crinoid arm regeneration

Abstract

Echinoderms are valuable test species in marine ecotoxicology and offer a wide range of biological processes appropriate for this approach. Regenerating echinoderms can be regarded as amenable experimental models for testing the effects of exposure to contaminants, particularly endocrine disrupter compounds (EDCs). As regeneration is a typical developmental process, physiologically regulated by humoral mechanisms, it is highly susceptible to the action of pseudo-hormonal contaminants which appear to be obvious candidates for exerting deleterious actions. In our laboratory experiments, selected EDCs suspected for their antiandrogenic action (p,p'-DDE and cyproterone acetate) were tested at low concentrations on regenerating specimens of the crinoid Antedon mediterranea. An integrated approach which combines exposure experiments and different morphological analyses was employed; the obtained results suggest an overall pattern of plausible endocrine disruption in the exposed samples, showing that processes such as regenerative growth, histogenesis, and differentiation are affected by the exposure to the selected compounds. These results confirm that (1) regenerative phenomena of echinoderms can be considered valuable alternative models to assess the effects of exposure to exogenous substances such as EDCs, and (2) these compounds significantly interfere with fundamental processes of developmental physiology (proliferation, differentiation, etc...) plausibly via endocrine alterations. In terms of future prospects, taking into account the increasing need to propose animal models different from vertebrates, echinoderms represent a group on which ecotoxicological studies should be encouraged and specifically addressed.

Chemical fate and biological effects of several endocrine disrupters compounds in two echinoderm species

“…increase in mean regenerate length), although an hormetic dose-response relationship was often observed-rather than a strictly dose-dependent relationship ). Different responses were observed following exposures to the putative anti-androgenic chemicals: DDE was again ineffective whereas CPA exposed samples displayed significantly reduced regenerate length compared to their controls (Sugni et al 2008).…”

“…After 1 week of exposure, regenerating arm length was not affected by most compounds and only TPT promoted the regenerative growth Sugni et al 2007Sugni et al , 2008. After 2 weeks of exposure, all the putative androgenic compounds (TPT, FEN, MET) were reported to have a general stimulatory effect on regeneration (i.e.…”

“…Therefore, they represent a potential threat especially for all those organisms living in contact with sediments, such as, for example, echinoderms. Until recent times, these animals and, in general, invertebrates were rather neglected in spite of their fundamental ecological relevance (Oehlmann and SchulteOehlmann 2003;Zou 2003;Sugni et al 2007Sugni et al , 2008. For this reason there is recent awareness of the urgent need of increasing the availability of suitable experimental models for testing EDCs on this group.…”

“…In some species regeneration is used even for asexual reproduction, as the animal spit in two or more parts and each one of these will regenerate the lacking portion to have a whole individual (Candia Carnevali 2005). As recently underlined (Candia Carnevali 2005;Sugni et al 2007Sugni et al , 2008, regenerating organisms are very sensitive models and can be considered optimal bio-indicators of environmental stress since they reproduce in adult organisms most of those processes (cell proliferation, differentiation, etc.) characteristic of the developmental stages, which are actually known to be very sensitive.…”

Laboratory Tests with Androgenic and Anti-Androgenic Pesticides – Comparative Studies on Endocrine Modulation in the Reproductive System of Invertebrates and Vertebrates

“…DDE inhibited spermatogenesis and reduced the egg size in female P. lividus but enhanced the egg size in Anterdon mediterranea (Lavado et al 2010). In experiments on echinoderm regenerative response DDE interfered with fundamental processes of developmental physiology via endocrine modulation of A. mediterranea (Sugni et al 2008).…”