0515 : Moringa oleifera seeds improve vascular function in aged Wistar rats

Vascular ageing is characterized by functional and structural changes of the vessel wall, decreased endothelial NO bioavailability, elevated vasoconstrictor and inflammatory mediators leading to endothelial dysfunction, vascular rigidity and tone impairment. Moringa oleifera (MOI) is a little tree used in Malagasy folk medicine to treat cardiovascular diseases. The present study evaluated MOI treatment effects in vascular ageing of Wistar rats. Male Wistar rats (47 weeks old) received food containing 750 mg/kg/day of MOI seed powder or normal food. A group of young Wistar rats (16 weeks old) was used as control. After 4 weeks, rats were sacrificed and vessels were harvested to evaluate vascular reactivity and protein expression by Western blot and immunostaining. Plasmatic levels of vasoactive substances were analyzed by ELISA and Griess methods. MOI treatment improved carbachol-dependent relaxation in both aortas and mesenteric arteries of aged rats. In aortas, this was associated with an increased endothelial-NO-synthase activation and Akt-signaling, caveolin-1 inhibition and enhanced L-arginine bioavailability through arginase I downregulation to a level comparable to that of young rats. In mesenteric arteries the improvement of the endothelial function was related to an EDHF-dependent mechanism. Furthermore, MOI seeds completely reversed the hyporeactivity to phenylephrine of aortas from aged rats, reduced inducible-NOsynthase expression and subsequent circulating NO. In addition, increased circulating prostacyclin without changes in vascular expressions of cyclooxygenases were found in aged treated rats. These results suggest a protective vascular role of MOI seeds against the vascular dysfunction due to ageing. The author hereby declares no conflict of interest