Fistular onion stalk extract exhibits anti-atherosclerotic effects in rats

Fistular onion stalk is used as a traditional herbal medicine, and its extract exhibits certain beneficial effects on cardiovascular disease. In this study, the effects of fistular onion stalk extract on the pathological features, circulating inflammatory cytokines, local renin-angiotensin-aldosterone system (RAAS) and signaling pathway activities were examined using an in vivo model of atherosclerosis. Atherosclerosis of the aorta was induced by loading Sprague Dawley rats with a high-fat diet and vitamin D₂. Fistular onion stalk extract administration began five weeks after the induction of atherosclerosis and continued for 12 weeks. Rats treated with fistular onion stalk extract showed a significant reduction in the pathological region compared with the vehicle-treated controls. Inhibition of atherosclerosis was associated with preservation of the vascular wall and immune cell infiltration. The extract also reduced the levels of the local inflammatory cytokines interleukin (IL)-1β, IL-6, monocyte chemoattractant protein-1 and tumor necrosis factor-α. Furthermore, the extract downregulated the local activity of the RAAS. In addition, extract treatment inhibited several inflammatory signaling pathways by preventing phosphorylation, including the nuclear factor κB, Janus kinase/signal transducers and activators of transcription and mitogen-activated protein kinase pathways. These data indicate that fistular onion stalk extract may be useful for the attenuation of atherosclerosis, and the mechanism includes the regulation of the local inflammatory response.