[Sodium restriction prevents cardiovascular remodeling associated with insulin-resistance in the rat]

In the present work, the objective was to evaluate the influence of a dietary sodium restriction on cardiovascular morphology changes associated with insulin-resistance.

At 8 weeks of age, rats were fed for 12 weeks a 60%-fructose diet containing a regular sodium content (0.64%) or totally lacking in sodium chloride (<0.01%). A group of rats fed a wheat starch-based diet with regular sodium content served as control group.

Elevated HOMA index and plasma insulin confirm the presence of insulin-resistance in fructose-fed rats. Concomitantly, an increase in cardiac mass and in cardiac collagen (Sirius red staining) was detected without obvious change in arterial pressure or cardiac aldosterone synthase mRNA expression. In addition, cross-sectional area of the carotid artery was higher in fructose-fed rats. Production of superoxide anion, equated with dihydroethidium (DHE) staining, was enhanced in cardiac tissue of rats with insulin-resistance. Withdrawal of sodium from the fructose diet prevented all the cardiovascular effects of fructose consumption, including DHE staining.

These results are in favor of the participation of oxidative stress normalization in the beneficial influence of dietary sodium deprivation on cardiovascular remodeling in this model of insulin-resistance in rats.