INVESTIGADORES
VENTURINO Andres
artículos
Título:
Antioxidant responses to azinphos methyl and carbaryl during the embryonic development of the toad Rhinella (Bufo) arenarum Hensel
Autor/es:
FERRARI A; LASCANO C; ANGUIANO O.L.; PECHEN DE D'ANGELO A.M; VENTURINO A
Revista:
AQUATIC TOXICOLOGY
Editorial:
Elsevier
Referencias:
Año: 2009 vol. 93 p. 37 - 44
ISSN:
0166-445X
Resumen:
Amphibian embryos are naturally exposed to prooxidant conditions throughout their development. Environmental
exposure to contaminants may affect their capacity to respond to challenging conditions,
to progress in a normal ontogenesis, and finally to survive and succeed in completing metamorphosis.
We studied the effects of the exposure to two anticholinesterase agents, the carbamate carbaryl
and the organophosphate azinphos methyl, on the antioxidant defenses of developing embryos of the
toad Rhinella (Bufo) arenarum. Reduced glutathione (GSH) levels were increased early by carbaryl, but
were decreased by both pesticides at the end of embryonic development. The GSH-dependent enzymes
glutathione reductase and glutathione peroxidases showed oscillating activity patterns that could be
attributed to an induction of activity in response to oxidative stress and inactivation by excess of reactive
oxygen species. Glutathione-S-transferases, which may participate in the conjugation of lipid peroxide
products in addition to pesticide detoxification, showed an increase of activity at the beginning and at the
end of development. Catalase also showed variations in the activity suggesting, successively, induction
and inactivation in response to pesticide exposure-induced oxidative stress. Superoxide dismutase activity
was increased by carbaryl and transiently decreased by azinphos methyl exposure. Judging from the
depletion in GSH levels and glutathione reductase inhibition at the end of embryonic development, the
oxidative stress causedby azinphosmethylseemedto be greater than that causedby carbaryl, whichmight
be in turn related with a higher number of developmental alterations caused by the organophosphate.
GSH content is a good biomarker of oxidative stress in the developing embryos exposed to pesticides. The
antioxidant enzymes are in turn revealing the balance between their protective capacity and the oxidative
damage to the enzyme molecules, decreasing their activity.