Dioscorea deltoidei (Dioscoreaceae) leaf extract exerts anti-atherosclerotic effect in rats via down-regulation of phosphorylated JAK/STAT

Abstract

Purpose: To investigate the effect of leaf extract of Dioscorea deltoidea (Dioscoreaceae) leaf (DDE) on atherosclerosis-induced aorta wall damage in a rat model, and the underlying mechanism of action.Methods: Rats were fed high-fat diet containing vitamin D2 for 16 weeks to induce atherosclerosis. Histopathological changes in the aorta were examined using hematoxylin and eosin (H & E) staining, while ELISA kits were used to measure cytokine levels.Results: Treatment with DDE significantly (p < 0.05) alleviated atherosclerosis-induced increase in mean lesion area in the rat aorta. The mean lesion area in atherosclerotic rats was decreased to 51.5, 21.2 and 2.3 mm2, on treatment with DDE at doses of 2.5, 5 and 10 mg/kg, respectively. Furthermore, DDE significantly suppressed atherosclerosis-induced elevation in IL-1β and IL-6 levels in the rat aorta (p < 0.05). The levels of MCP-1 and TNF-α decreased in the artherosclerotic rats on treatment with DDE. In DDE-treated rats, the atherosclerosis-induced increase in the levels of Ang II, AT1, AT2, p-STAT3, p-p65 and p-p38 were significantly decreased, relative to the model group (p < 0.05). However, DDE treatment did not alter the levels of total STAT3, p65 and p38 in the rat aorta tissues.Conclusion: These results indicate that DDE inhibits inflammatory response and atherosclerosisinduced damage to aorta wall. Moreover, RAAS expression, inflammatory cytokines and JAK/STAT signalling pathway were down-regulated in atherosclerotic rats on treatment with DDE. Thus, DDE may be a potential source of drug for the management of atherosclerosis.