Developmental alterations in Rhinella arenarum embryos caused by the exposure to the organophosphate Chlorpyrifos

SOTOMAYOR V; LASCANO C; PECHEN DE D'ANGELO A.M.; VENTURINO A

ENVIRONMENTAL TOXICOLOGY AND CHEMISTRY

SETAC PRESS

Año: 2012 vol. 31 p. 2052 - 2058

0730-7268

Organophosphorus pesticides (OP) are widely applied in the Alto Valle of Río Negro and Neuquén due to intensive fruit growing. Amphibians are particularly sensitive to environmental pollution and OP may transiently accumulate in ponds and channels of the region during their reproductive season. OP exposure may alter amphibian embryonic development and the reproductive success of autochthonous species. In this study, embryos of the common toad Rhinella arenarum were employed to assess developmental alterations and to study polyamine (PA) metabolism, which is essential to normal growth, as a possible target underlying the effects of the OP chlorpyrifos (CPF). As the duration of CPF exposure increased and embryonic development progressed, the LC50 values decreased and the percentage of malformed embryos increased. Developmental arrest was also observed and several morphological alterations were recorded, such as incomplete and abnormal closure of the neural tube, dorsal curvature of the caudal fin, reduction of body size and caudal fin length, atrophy and edema. An early decrease in ornithine decarboxylase (ODC) activity and PA levels was also observed in embryos exposed to CPF. The decrease in PA contents in tail bud embryos might be a consequence of the reduction in ODC activity. The alteration of PA metabolism occurred before embryonic growth was interrupted and embryonic malformations were observed, and may be useful as a biomarker in environmental studies.