Lentil polyphenol extract prevents angiotensin II-induced hypertension, vascular remodelling and perivascular fibrosis

Abstract

The objective of the study was to investigate whether chronic administration of the Morton lentil polyphenol extract (MLPE), which possesses rich phenolic compounds and a high antioxidant activity, had any protective effects on angiotensin II-induced hypertension. After four weeks of subcutaneous infusion of angiotensin II (200 ng kg⁻¹ min⁻¹) in male SD rats, the water intake and mean artery pressure was significantly increased by 39.8% and 48.3%, respectively, as compared with the control. The media/lumen ratio of the small arteries in the heart and kidneys were increased by 117% and 168% by angiotensin II infusion. The perivascular fibrosis was increased by 65% and 32% in the heart and kidneys, respectively. Levels of the reactive oxygen species in the aorta was enhanced by 115.8%. In another group of rats, which received four weeks of lentil extract administration (1% freeze-dried MLPE in the drinking water), followed by another four weeks of extract administration plus angiotensin II infusion, the angiotensin II-induced enhancement in water intake and mean artery pressures decreased by 12.7% and 8.2%, respectively, as compared with the rats that received angiotensin II infusion alone. The angiotensin II-induced rats showed increases in the media/lumen ratios which were attenuated by 43.6% and 47.2% in the small arteries of heart and kidneys, respectively. Angiotensin II-induced perivascular fibrosis was attenuated by 30% and 26% in the rats that received the extract. Angiotensin II-induced rats showed reactive oxygen species levels in the aorta was reduced by 48.9%. These findings demonstrated that lentil extract attenuated angiotensin II-induced hypertension and associated pathological changes, including remodelling and perivascular fibrosis in the small resistant arteries of heart and kidneys.