Endogenous and Exogenous Antioxidant Protection for Endothelial Dysfunction

We performed "in vitro" experiments using human mammary artery rings, in order to examine the effect of endogenous and exogenous antioxidants on endothelial-dependent vasodilatation induced by cumulative doses (10(-9) M - 10(-4) M) of adenosine (ADP) and to study the effect on endothelial - independent vasodilatation induced by cumulative doses (10(-9) M - 10(-4)M) of sodium-nitroprusside (NSP), respectively. Our results showed that 1 hour pre-incubation with triglyceride diminished the endothelial-dependent vasodilator response to ADP, but it has not modified the endothelial -independent vasodilator response to NSP. Vascular response was expressed as maximal vasodilatation from the 10(-5) M phenilephrine (PE) induced pre-contraction, considered as reference. One hour co-incubation of the rings with triglyceride and antioxidant factors, such as 10(-3) M reduced glutathione (GSH) or 10(-3) M ascorbic acid significantly reduced the impairment of the vasodilatation response to ADP (p = 0.02 for GSH, and p = 0.008 for ascorbic acid) but has not modified the vasodilatation response to NSP. As a conclusion, the endothelial dysfunction induced by the triglyceride could contribute to the pathogenesis of atherosclerosis and the treatment with high doses of antioxidants could "protect" the endothelium against the pro-atherogenic action of the triglyceride.