Aim: 

The erythrocyte is considered an excellent cell to study the oxidative status because it accumulates high levels of both, Fe²⁺ and oxygen, and the adult circulating forms can not renew its protein stocks. We examined the effects of fish oil (FO)- and olive oil (OO)-rich diets on erythrocyte susceptibility to oxidative stress.

Methods: 

Rats were fed for 16 weeks diets containing 50 g lipids/kg; either OO, maize oil (MO) or FO. OO or MO diets contained a standard amount (100 mg/kg) of all-rac-alpha-tocopheryl acetate (vitamin E). FO diets were supplemented with 0, 100 or 200 mg all-rac-alpha-tocopheryl acetate/kg. At the end of the feeding period, we measured erythrocyte and reticulocyte count. Also, ATP and BPG erythrocyte concentrations (to evaluate the metabolic status) and GSH and GSH/GSSG (to estimate the cellular redox balance) were measured after two hours incubation at 37°C in a glucose-PBS (controls) and in the presence of 5 mM H₂O₂ to increase oxidative stress. Erythrocyte life span was evaluated in vivo by the ⁵¹Cr labelling method.

Results and Conclusion: 

Our results indicate that the diets did not affect ATP or BPG concentrations. However, erythrocyte GSH levels of rats fed FO were significantly lower in both controls and in the presence of H₂O₂. GSH levels were slightly recovered when vitamin E was added. Erythrocyte life span was slightly lower, but not statistically significant, in FO fed rats. Reticulocyte count increased in FO fed rats. The study suggests that FO, but not the OO diet, makes erythrocytes more susceptible to the oxidative stress.