tEndosulfan is a persistent organic pollutant (POP) that has lethal and sublethal effects on non-targetorganisms, including amphibians. In a laboratory study, we investigated direct and post-exposure effectsof endosulfan on Bufo bufo tadpoles. For this purpose we exposed the tadpoles to a single short-term con-tamination event (96 h) at an environmentally-realistic concentration (200 g endosulfan/L). This wasfollowed by a recovery period of 10 days when the experimental animals were kept in pesticide-freewater. The endpoints were assessed in terms of mortality, incidence of deformity, effects on behavior,and the morpho-functional features of the epidermis. We found that a short-term exposure to the testedconcentration of endosulfan did not cause mortality but induced severe sublethal effects, such as hyper-activity, convulsions, and axis malformations. Following relocation to a pesticide-free environment, wenoted two types of response within the experimental sample, in terms of morphological and behav-ioral traits. Moreover, by using both ultrastructural and a morpho-functional approach, we found that ashort-term exposure to endosulfan negatively affected the amphibian epidermis. We also observed sev-eral histo-pathological alterations: increased mucous secretion, an increase in intercellular spaces andextensive cell degeneration, together with the induction of an inducible isoform of nitric oxide synthase(iNOS).Following the post-exposure period, we found large areas of epidermis in which degenerationphenomena were moderate or absent, as well as a further increase in iNOS immunoreactivity. Thus,after 10 days in a free-pesticide environment, the larval epidermis was able to partially replace elementsthat had been compromised due to a physiological and/or a pathological response to the pesticide. Theseresults highlight the need for both exposure and post-exposure experiments, when attempting to assesspollutant effects.
Exposure and post-exposure effects of endosulfan on Bufo bufo tadpoles: Morpho-histological and ultrastructural study on epidermis and iNOS localization
Bernabò, I;Guardia, A.;La Russa, D;Madeo, G;TRIPEPI, Sandro;BRUNELLI, Elvira
Project Administration
2013-01-01
Abstract
tEndosulfan is a persistent organic pollutant (POP) that has lethal and sublethal effects on non-targetorganisms, including amphibians. In a laboratory study, we investigated direct and post-exposure effectsof endosulfan on Bufo bufo tadpoles. For this purpose we exposed the tadpoles to a single short-term con-tamination event (96 h) at an environmentally-realistic concentration (200 g endosulfan/L). This wasfollowed by a recovery period of 10 days when the experimental animals were kept in pesticide-freewater. The endpoints were assessed in terms of mortality, incidence of deformity, effects on behavior,and the morpho-functional features of the epidermis. We found that a short-term exposure to the testedconcentration of endosulfan did not cause mortality but induced severe sublethal effects, such as hyper-activity, convulsions, and axis malformations. Following relocation to a pesticide-free environment, wenoted two types of response within the experimental sample, in terms of morphological and behav-ioral traits. Moreover, by using both ultrastructural and a morpho-functional approach, we found that ashort-term exposure to endosulfan negatively affected the amphibian epidermis. We also observed sev-eral histo-pathological alterations: increased mucous secretion, an increase in intercellular spaces andextensive cell degeneration, together with the induction of an inducible isoform of nitric oxide synthase(iNOS).Following the post-exposure period, we found large areas of epidermis in which degenerationphenomena were moderate or absent, as well as a further increase in iNOS immunoreactivity. Thus,after 10 days in a free-pesticide environment, the larval epidermis was able to partially replace elementsthat had been compromised due to a physiological and/or a pathological response to the pesticide. Theseresults highlight the need for both exposure and post-exposure experiments, when attempting to assesspollutant effects.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
