Effects of in vivo iron exposure on oxidative stress in the temperate bivalve Mya arenaria

GONZÁLEZ, P.M.; MALANGA, G. Y PUNTARULO, S.

Tucuman

Otro; XLV Reunión Anual SAIB; 2009

SAIB

The aim of this study was to evaluate the effect of in vivo Fe exposure over the oxidative metabolism of Mya arenaria. Bivalves were placed in aquaria with natural seawater supplemented with 500 mM Fe. Digestive glands (GD) were isolated and total Fe content, measured spectrophotometrically, resulted in a significant increase after 9 to 17 days of exposure. After 2 days of treatment, the content of thiobarbituric acid reactive substances, measured spectrophotometrically, showed a significant increase (3.8-fold), decreasing to control values after 7 days and increasing constantly from day 7 to day 17. Ascorbyl radical content, measured by electronic paramagnetic resonance (EPR), showed a significant increase at day 2 (4-fold) and 9 (25-fold), as compared to controls. The labile Fe pool significantly increased over control values from day 7 until day 17. Nitrate and nitrite content, measured by Griess reaction; and nitric oxide (NO) content, assessed by EPR, decreased on day 2 with no further alteration until day 17 suggesting a role for NO in the Fe mediated effect. These data showed that at early stages of Fe exposure, Fe uptake is limited and an initial phase of damage could be adequately controlled by the cells. However, after 7 days of treatment, endogenous Fe increased continuously, severely damaging the cells leading to injury and death.