title: Attenuation of blood pressure in spontaneously hypertensive rats by acupuncture was associated with reduction oxidative stress and improvement from endothelial dysfunction.
abstract: BACKGROUND
  Hypertension can be treated effectively by acupuncture; however, the association between acupuncture and endothelial function remains unknown. This study aimed to investigate the effects of acupuncture on endothelial dysfunction and oxidative stress-related parameters in spontaneously hypertensive animals.
  
  
  METHODS
  Eighteen-week-old Wistar-Kyoto rats (WKYs) and spontaneously hypertensive rats (SHRs) were arbitrarily divided into four groups: WKY control (n = 8), SHR control (n = 8), SHR sham-acupuncture (n = 8) and SHR acupuncture (n = 8). The SHR acupuncture group had electroacupuncture for 6 consecutive weeks on acupoints ST36 and LR3. Blood pressure was monitored during the treatment period, and animals were euthanized at the 6th week. Aortas were harvested for determination of angiotensin II levels, NADPH oxidase activity and nitrate/nitrite levels. The level of reactive oxygen species (ROS) was determined by dihydroethidium (DHE) imaging, and functional studies were performed to assess vascular reactivity. Endothelial nitric oxide synthase was measured by Western blot assay.
  
  
  RESULTS
  Blood pressure at the end of treatment was significantly lower in the SHR acupuncture group (185.0 ± 5.6 mmHg) compared with the SHR sham-acupuncture and the SHR control groups (201.0 ± 5.4 and 197.4 ± 5.9 mmHg, respectively; P < 0.001). Serum angiotensin II level in the SHR control group was significantly higher than in the WKY control group (P < 0.001), while it was significantly attenuated by acupuncture treatment (P = 0.023). DHE staining showed that ROS level was reduced in the aortas (P = 0.0017) and carotid arteries (P = 0.039) of acupuncture-treated SHRs. Biochemical assays showed that acupuncture inhibited the NADPH oxidase activity (P = 0.022) and enhanced antioxidant capacity (P = 0.0039). In functional studies, endothelium-dependent relaxation of aortic rings (P = 0.018) and carotid arteries (P = 0.022) in response to acetylcholine was improved in the SHR acupuncture group. Aortas of SHRs receiving acupuncture also expressed an elevated level of eNOS (P > 0.001) and p-eNOS (P = 0.012) and a reduced nitrotyrosine level (P = 0.0012). The nitrate/nitrite level in aortic tissue was also attenuated after acupuncture (P = 0.0018).
  
  
  CONCLUSIONS
  The effects of acupuncture in treating hypertension were associated with reduced oxidative stress, increased nitric oxide bioavailability and endothelial function in SHRs.
authors: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, People's Republic of China.
authors: Sin Bond
authors: SB
authors: Leung
authors: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, People's Republic of China.
authors: Hongwei
authors: H
authors: Zhang
authors: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, People's Republic of China.
authors: Chi Wai
authors: CW
authors: Lau
authors: School of Chinese Medicine, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong, People's Republic of China.
authors: Zhi-Xiu
authors: ZX
authors: Lin
keywords: Acupuncture; Endothelial dysfunction; Hypertension; Spontaneously hypertensive rats