Antioxidant metabolism and development in Bufo arenarum embryos exposed to azynphos methyl

LASCANO C; FERRARI A; VENTURINO A

Mar del PLata

Congreso; 43ª Reunión Anual de la SAIB; 2007

SAIB

Amphibians are very susceptible to environmental contaminants, being the toad B. arenarum particularly threatened during its embryonic development by the massive application of the organophosphate azynphos methyl (AM) used for pest control in Norpatagonia valleys. Our objective is to determine if reactive oxygen species (ROS) in connection with altered polyamine (PA) metabolism contribute to altered embryonic development. Embryos were continuously exposed until complete development to 0.5, 2 and 9mg/l AM. Antioxidant enzyme activities were measured. Catalase was early increased by 0.5mg/lAM returning to control levels thereafter.GSHreductase was also early increased by all doses of AM, while GSH peroxidase tended to decrease at late stages. GST was not affected by AM. Putrescine levels increased throughout development, rising significantly in exposed embryos, while spermidine and spermine were decreased in late embryos exposed to 9mg/l AM. These effects are accompanied with a dose dependent increase in the number of embryonic malformations. The results suggest that catalase and GSH reductase are early induced in response to mild exposure to AM, while in later embryonic stages the antioxidant enzymes are altered by the increase of oxidative stress. PA levels suggest an oxidative metabolization to putrescine, contributing to oxidative stress and altered development.