Sublethal concentrations of azinphos-methyl induce biochemical and morphological alterations in Rhinella arenarum embryos

LASCANO C; FERRARI A; VENTURINO A

CHEMISTRY AND ECOLOGY

TAYLOR & FRANCIS LTD

Lugar: Londres; Año: 2011 vol. 27 p. 557 - 568

0275-7540

Considering that amphibians are good sentinels of environmental conditions, Rhinella arenarum embryos were used to investigate the effects of sublethal concentrations of the organophosphorus insecticide azinphos-methyl, focusing on the appearance of morphological alterations and its possible connection with anticholinesterasic or pro-oxidant actions. Early R. arenarum embryos exposed to azinphos-methyl displayed a protective response through glutathione S-transferase induction along with superoxide dismutase inhibition. At intermediate embryonic stages, embryos exposed to azinphos-methyl displayed superoxide dismutase inhibition and morphological alterations, although cholinesterase activity was not altered, suggesting that other molecular targets different from cholinesterase were involved in the development of morphological alterations. At the end of embryonic development, a decrease in reduced glutathione as well as cholinesterase inhibition were observed, along with a significant increase in the number of malformed embryos. The connection between biochemical alterations and the appearance of malformations was not evident in R. arenarum embryos. However, increased glutathione S-transferase and decreased superoxide dismutase activities could be considered as early markers of exposure to azinphos-methyl. The results obtained demonstrate that sublethal concentrations of azynphos-methyl are a serious threat for toad embryos in their natural habitats since biochemical and morphological alterations could impair their ability to deal with an environmental stress situation.