Dual behavior of N-acetylcysteine during ethanol-induced oxidative stress in embryonic chick brains

Ethanol (EtOH) causes oxidative stress in embryos. Because N-acetylcysteine (NAC) failures and successes in ameliorating EtOH-induced oxidative stress have been reported, the objective was to determine if exogenous NAC ameliorated EtOH-induced oxidative stress within embryonic chick brains.

Control eggs were injected with approximately 25 µl of water on day 0, 1, and 2 of development (E_0-2). Experimental eggs were injected with dosages of either 3.0 mmol EtOH/kg egg; 747 µmol NAC/kg egg; 3.0 mmol EtOH and 747 µmol NAC/kg egg; 1000 µmol NAC/kg egg; or 3.0 mmol EtOH and 1000 µmol NAC/kg during the first 3 days of development (E_0-2). At 11 days of development (E₁₁; late embryogenesis), brains were harvested and subsequently assayed for oxidative stress markers including the loss of long-chain membrane polyunsaturated fatty acids (PUFAs); the accumulation of lipid hydroperoxides (LPO); decreased glutathione (GSH) and glutathione/glutathione disulfide (GSSG) levels; and decreased glutathione peroxidase (GPx) activities.

EtOH (3 mmol/kg egg), medium NAC (747 µmol/kg egg), and EtOH and medium NAC promoted oxidative stress. These treatments caused decreased brain membrane long-chain PUFAs; increased LPO levels; decreased GSH levels and GSH/GSSG levels; and decreased Se-dependent GPx activities. High NAC dosages (1000 µmol/kg egg) attenuated EtOH-induced oxidative stress within EtOH and high NAC-treated chick brains.

Exogenous EtOH and/or medium NAC propagated oxidative stress. Meanwhile, high NAC ameliorated EtOH-induced oxidative stress.