Chronic ethanol ingestion induces aortic inflammation/oxidative endothelial injury and hypertension in rats

Abstract

The study aim was to investigate the relationship of chronic ethanol-induced inflammation leading to vascular endothelial injury and elevation of blood pressure (BP) in a rat model. Male Fisher rats were divided into two groups of six animals each and treated as follows: (1) Control (5% sucrose, orally) daily for 12 weeks and (2) 20% ethanol (4 g kg^-1, orally) daily for 12 weeks. The mean arterial blood pressure was recorded every week. The animals were anesthetized with pentobarbital after 12 weeks; thoracic aorta were isolated and analyzed for aortic reactivity response, inflammatory mediators, oxidant/antioxidant enzyme protein expression and endothelial nitric oxide-generating system. The results show that the mean BP was significantly elevated 12 weeks after ethanol ingestion. The increased BP was related to increased aortic inflammation (tumor necrosis factor [TNF]-α; nitric oxide synthase [iNOS], COX-2 and MCP-1 protein expression) and elevated angiotensin II levels in alcohol-treated group compared to control. Aortic Nicotinamide adenine dinucleotide phosphate reduced (NADPH) oxidase activity, membrane and cytosolic subunits p22 ^phox and p47 ^phox expression and Mn-SOD activity and protein expression significantly increased, whereas nitric oxide (NO), endothelial NO synthase (eNOS), vascular endothelial growth factor (VEGF)-A and CuZn-SOD activity and protein expression significantly decreased in alcohol-treated group compared to control. The acetylcholine-mediated vasorelaxation response was depressed in the aorta of ethanol-treated rats compared to control. In conclusion, chronic ethanol-induced elevation in BP is related to increased aortic inflammation, elevated angiotensin II levels, induction of NADPH oxidase causing endothelial injury, depletion of CuZn-SOD, down-regulation of endothelial NO generating system and impaired vascular relaxation in rats.