Da-Chuan-Xiong Decoction Ameliorates Sodium Sensitivity and Plasma Norepinephrine via Attenuation of Brain Oxidative Stress in the DOCA-Salt Hypertensive Rats

Abstract

Background. Da-Chuan-Xiong Decoction (DCXD) is an aqueous extract from a classic Chinese herbal formula composed of dried rhizomes of Ligusticum chuanxiong Hort and Gastrodia elata Bl. in the mass ratio of 4 : 1. It has been long used to treat chronic cardiovascular disease caused by blood stasis and wind pathogen in the clinic. This experimental study aimed to investigate the blood pressure (BP)-lowering effect of DCXD treatment on hypertension and underlying mechanisms. Methods. Male Sprague–Dawley rats were used in the experiment, and the hypertensive models were created by administering deoxycorticosterone acetate (DOCA) in conjunction with a high salt intake in uninephrectomized rats. DCXD was administered to hypertensive rats by oral gavage daily at a dose of 5 g/kg or 2.5 g/kg bodyweight for 28 days. The brain sodium sensitivity, ENaC function, superoxide anion level, NADPH oxidase activity, and expression of ENaC, p67phox, p47phox, and Rac1 in the paraventricular nucleus were assessed by using the appropriate methods. Results. The 28 days of DCXD (5 g/kg) treatment significantly reduced the increased BP effectively, inhibited the enhanced heart index, kidney index, and 24 h urinary protein, and improved the progressive pathological changes of heart and kidney, which was comparable to that of the positive control amlodipine. DCXD treatment also caused a marked reduction in plasma norepinephrine and induced a significant improvement in brain sodium sensitivity and ENaC function in DOCA-salt hypertensive rats. Rats in DCXD-treated groups also exhibited decreased superoxide anion levels and NADPH oxidase activity in the paraventricular nucleus. The level of ENaC, p67phox, and Rac1 protein expression in the paraventricular nucleus was significantly downregulated by DCXD treatment in DOCA-salt hypertensive rats. Conclusions. These findings indicate that the depressor action and sympathetic inhibition of DCXD on salt-sensitive hypertension may be by ameliorating brain sodium sensitivity, modulating ENaC function, and inhibiting the expression of ENaC and NADPH oxidase in the hypothalamic paraventricular nucleus.