Electroacupuncture-related changes of NADPH-diaphorase and neuronal nitric oxide synthase in the brainstem of spontaneously hypertensive rats

Regulation of Hypertension for Secondary Prevention of Stroke: The Possible 'Bridging Function' of Acupuncture

Worldwide, stroke is the leading cause of mortality and disability, with hypertension being an independent risk factor for a secondary stroke. Acupuncture for the treatment of hypertension gains more attention in alternative and complementary medicine, but the results are inconsistent. Few studies regarding the secondary prevention of stroke by managing hypertension with acupuncture have been carried out as there are some problems regarding the antihypertensive drug status in the secondary prevention of stroke. Still, the potential of acupuncture in regulating the blood pressure for secondary stroke prevention deserves our focus. This review is based on papers recorded in the PubMed, Embase, and Web of Science databases, from their inception until March 28, 2017, and retrieved with the following search terms: hypertension and acupuncture, limited in spontaneously hypertensive rats (SHRs), stress-induced (or cold-induced) hypertensive or pre-hypertensive models. We find that, in these hypertensive animals, acupuncture could mainly influence factors related to the nervous system, oxidative stress, the endocrine system, cardiovascular function, and hemorheology, which are closely associated with the stroke outcome. This trend may give us a hint that acupuncture might well participate in the secondary prevention of stroke through these pathways when used in the management of hypertension.

Long-Term Stimulation with Electroacupuncture at DU20 and ST36 Rescues Hippocampal Neuron through Attenuating Cerebral Blood Flow in Spontaneously Hypertensive Rats

This study was designed to investigate the effect of long-term electroacupuncture at Baihui (DU20) and Zusanli (ST36) on cerebral microvessels and neurons in CA1 region of hippocampus in spontaneously hypertensive rats (SHR). A total of 45 male Wistar rats and 45 SHR were randomly grouped, with or without electroacupuncture (EA) at DU20 and ST36, once every other day for a period of 8 weeks. The mean arterial pressure (MAP) was measured once every 2 weeks. Cerebral blood flow (CBF) and the number of open microvessels in hippocampal CA1 region were detected by Laser Doppler and immunohistochemistry, respectively. Nissl staining and Western blotting were performed, respectively, to determine hippocampus morphology and proteins that were implicated in the concerning signaling pathways. The results showed that the MAP in SHR increased linearly over the observation period and was significantly reduced following electroacupuncture as compared with sham control SHR rats, while no difference was observed in Wistar rats between EA and sham control. The CBF, learning and memory capacity, and capillary rarefaction of SHR were improved by EA. The upregulation of angiotensin II type I receptor (AT1R), endothelin receptor (ETAR), and endothelin-1 (ET-1) in SHR rats was attenuated by electroacupuncture, suggesting an implication of AT1R, ETAR, and ET-1 pathway in the effect of EA.

The effects of acupuncture on the levels of blood pressure and nitric oxide in hypertensive patients

Hypertension possess a significant risk factor for a variety of diseases and affects millions of people all around the world. Recent studies suggest that NO plays a role in pathogenesis of hypertension while some investigators find a close relationship between acupuncture treatment and NO levels. We therefore aimed to investigate the effect of acupuncture on the levels of blood pressure and nitric oxide (NO) in hypertensive patients. After obtaining institutional ethics committee approval and patients' informed consent, 32 essential hypertensive patients aged between 32-65 and taking antihypertensive drugs were included to the study. A total of 10 sessions of manual acupuncture were applied on body acupoints (EX-HN3 (Yintang), KI 3, LIV 3, SP 9, LI 4, HT 7, ST 36, SP 6) in 10 weeks. Systolic (SBP) and diastolic blood pressure (DBP) levels and blood NO levels were measured for 3 times (i.e. before & after the first session, and after the 10th session). Main outcome measures of our study were the changes in SBP and DBP as well as nitric oxide levels between 3 measurements were compared. Our study showed that SBP and DBP values decreased both after the 1st and 10th sessions of acupuncture treatments (p<0.05). The NO concentration also increased both after the 1st (71.5%) and 10th sessions (184.6%) (p<0.05).

Electroacupuncture Delays Hypertension Development through Enhancing NO/NOS Activity in Spontaneously Hypertensive Rats

Using spontaneously hypertensive rats (SHR), this study investigated whether electroacupuncture (EA) could reduce early stage hypertension by examining nitric oxide (NO) levels in plasma and nitric oxide synthase (NOS) levels in the mesenteric resistance artery. EA was applied to the acupuncture point Governor Vessel 20 (GV20) or to a non-acupuncture point in the tail twice weekly for 3 weeks under anesthesia. In conscious SHR and normotensive Wistar Kyoto (WKY) rats, blood pressure was determined the day after EA treatment by the tail-cuff method. We measured plasma NO concentration, and evaluated endothelial NO syntheses (eNOS) and neuronal NOS (nNOS) protein expression in the mesenteric artery. Systolic blood pressure (SBP) and diastolic blood pressure (DBP) were lower after 3 weeks of GV20 treatment than EA at non-acupuncture point and no treatment control in SHR. nNOS expression by EA was significantly different between both WKY and no treatment SHR control, and EA at GV20 in SHR. eNOS expression was significantly high in EA at GV 20 compared with no treatment control. In conclusion, EA could attenuate the blood pressure elevation of SHR, along with enhancing NO/NOS activity in the mesenteric artery in SHR.

Electroacupuncture inhibits inflammation reaction by upregulating vasoactive intestinal Peptide in rats with adjuvant-induced arthritis

Acupuncture is emerging as an alternative therapy for rheumatoid arthritis (RA). However, the molecular mechanism underlying this beneficial effect of acupuncture has not been fully understood. Here, we demonstrated that electroacupuncture at acupoints Zusanli (ST36), Xuanzhong (GB39); and Shenshu (BL23) markedly decreased the paw swelling and the histologic scores of inflammation in the synovial tissue, and reduced the body weight loss in an adjuvant-induced arthritis rat model. However, the electrical stimulation at nonacupoint did not produce any beneficial effects against the experimental arthritis. Most interestingly, the electroacupuncture treatment resulted in an enhanced immunostaining for vasoactive intestinal peptide (VIP), a potent anti-inflammatory neuropeptide, in the synovial tissue. Moreover, the VIP-immunostaining intensity was significantly negatively correlated with the scores of inflammation in the synovial tissue (r = −0.483, P = .0026). In conclusion, these findings suggest that electroacupuncture may offer therapeutic benefits for the treatment of RA, at least partially through the induction of VIP expression.

Effects of electro-acupuncture on endothelium-derived endothelin-1 and endothelial nitric oxide synthase of rats with hypoxia-induced pulmonary hypertension

Pulmonary hypertension (PH) is characterized by elevated pulmonary artery pressure (PAP), pulmonary vascular remodeling and right ventricular hypertrophy, which are mainly due to endothelial dysfunction. Electro-acupuncture has shown beneficial effects on cardiovascular homeostasis, but little evidence has been obtained on pulmonary effects. The goal of the present study was to investigate whether electro-acupuncture on bladder-13 and -15 points can protect against chronic hypoxia-induced PH by regulating endothelium-derived endothelin (ET)-1 and endothelial nitric oxide synthase (eNOS). Male Wistar rats were exposed to hypoxia to induce PH. Hemodynamic analysis revealed that mean PAP was similar under normoxic conditions. Chronic hypoxia increased mean PAP to 37 ± 3 mmHg, and electro-acupuncture attenuated it to 29 ± 3 mmHg. Absolute right ventricular weight was ameliorated by electro-acupuncture from 0.288 ± 0.048 g to 0.228 ± 0.029 g under hypoxic conditions. Hypoxia-induced right ventricular hypertrophy index decreased from 0.477 ± 0.069 to 0.378 ± 0.053 with electro-acupuncture treatment. Histological examination revealed that hypoxic rats showed increased medial pulmonary artery wall thickness as well as muscularization. However, these alternations by chronic hypoxia were attenuated by electro-acupuncture. There was no difference in eNOS or ET-1 between groups under normoxic conditions. Electro-acupuncture treatment significantly improved the circulating eNOS concentration (365.36 ± 31.51 pg/mL) compared with only hypoxia exposure (247.60 ± 30.64 pg/mL). In lung homogenate, levels of eNOS under hypoxia increased from 684.96 ± 117.90 to 869.86 ± 197.61 pg/mg by electro-acupuncture treatment. Levels of ET-1 changed oppositely to eNOS in response to electro-acupuncture (ET-1 in plasma, 29.44 ± 2.09 versus 20.70 ± 2.37 pg/mL; ET-1 in lung homogenate, 120.51 ± 3.03 versus 110.60 ± 4.04 pg/mg). In conclusion, these results indicated that treatment with electro-acupuncture can protect against hypoxia-induced PH, possibly by regulating the balance of endothelium-derived vasoconstrictors and vasodilators.

Electroacupuncture decreases nitric oxide synthesis in the hypothalamus of spontaneously hypertensive rats

Acupuncture-related effects on autonomic function have been explored via biological and neurophysiologic studies. The hypothalamus, known to regulate the autonomic nervous system, is likely affected by acupuncture treatment that modulates sympathetic functions. The aim of this study was to investigate the effect of electroacupuncture at the Jogsamni point (ST36, an acupoint known to modulate autonomic function) on expression of neuronal nitric oxide synthase (nNOS) in the hypothalamus of spontaneously hypertensive rat. Nitric oxide, which is produced by nNOS activity, plays an important role in the regulation of many physiologic processes, including sympathetic activities, in the hypothalamus and other parts of the brain. nNOS expression was assessed by immunohistochemistry of nNOS and histochemistry of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d). The staining intensities of nNOS-positive neurons and NADPH-d-positive neurons were quantitatively assessed using microdensitometry to measure changes in optical density. The results show that electroacupuncture at ST36 reduced the expression and activity of nNOS in the hypothalamus of spontaneously hypertensitive rats. These findings suggest that the electroacupuncture at ST36 results in modulation of the activity of nNOS in the hypothalamus of spontaneously hypertensive rat.