Objective: To observe the effects of pre-electroacupuncture at "Taichong"(LR3), "Neiguan"(PC6) and "Waiguan"(TE5) on blood pressure and cardiac function of high-salt-induced hypertension rats, so as to explore the possible mechanism of pre-electroacupuncture in improving hypertension.
Methods: Twenty-four SD rats were randomly divided into control group, high-salt group and pre-electroacupuncture group, with 8 rats in each group. The hypertension model was established by feeding high-salt diet for 7 weeks. In the pre-electroacupuncture group, rats received electroacupuncture intervention at bilate-ral LR3, PC6 and TE5 (2 Hz/15 Hz, 2 mA) for 30 min, once a day, from the first day of modeling, for a total of 7 weeks. The blood pressure of rats was monitored by caudal artery noninvasive blood pressure measurement technique before and at the 1st, 3rd, 5th and 7th week of modeling. At the 8th week of the experiment, left ventricular catheterization was performed and biological signal acquisition system was used to detect left ventricular hemodynamics indexes and analyze left ventricular function, the car-diac mass ratio was measured to evaluate the degree of myocardial hypertrophy. The mRNA expressions of atrial natriuretic peptide(ANP), myosin heavy chain 7(MYH7), α-smooth muscle actin(α-SMA), interleukin(IL)-1β, and IL-6 of myocardial tissues were detected by quantitative real-time PCR. Sirius red staining was used to observe the degree of myocardial fibrosis.
Results: Compared with the control group, systolic blood pressure, diastolic blood pressure, mean arterial pressure, left ventricular end-diastolic pressure (LVEDP), cardiac mass ratio，and the mRNA expressions of ANP, MYH7, α-SMA, IL-1β, and IL-6, and sirius red staining area of myocardium were all significantly increased(P<0.01,P<0.05)，maximal rate of rise and descent of left ventricular pressure(LVP±dP/dtmax) were decreased (P<0.05,P<0.01) in the high-salt group. Compared with the high-salt group, rats in the pre-electroacupuncture group had lower systolic blood pressure, diastolic blood pressure, mean arterial pressure, LVEDP，cardiac mass ratio，higher LVP±dP/dtmax,down-regulated mRNA expressions of ANP, MYH7, α-SMA, IL-1β, IL-6, and smaller area of sirius red staining(P<0.05, P<0.01).
Conclusion: Pre-electroacupuncture tends to lower blood pressure, improve cardiac function and reduce myocardial fibrosis in high-salt-induced hypertension rats, which may be associated with inhibiting inflammatory response.
目的：观察预电针“太冲”“内关”“外关”对高盐诱导高血压大鼠血压和心功能的影响，并探讨其可能的作用机制。方法：SD大鼠随机分为对照组、高盐组、预电针组，每组8只。采用高盐饲料喂养7周诱导高血压大鼠模型。预电针组自造模第1天起予“太冲”“内关”“外关”电针干预，每次30 min，每日1次，连续7周。分别于造模第0、1、3、5、7周采用尾动脉无创血压测量技术监测大鼠血压，第8周利用左心室导管术检测大鼠左心室功能，测定心脏质量比评估心肌肥大程度，实时荧光定量PCR法检测大鼠心肌组织心房钠尿肽(ANP)、肌球蛋白重链7(MYH7)和α-平滑肌肌动蛋白(α-SMA)及白细胞介素(IL）-1β、IL-6 mRNA表达，天狼星红染色观察大鼠心肌纤维化程度。结果：与对照组比较，高盐组大鼠收缩压、舒张压、平均动脉压和左心室舒张末期压力(LVEDP)、心脏质量比均升高(P<0.01，P<0.05)，左心室压最大上升速率(+dP/dtmax)和最大下降速率(dP/dtmax)绝对值均降低(P<0.01)，心肌组织ANP、MYH7、α-SMA及IL-1β、IL-6 mRNA表达均上调(P<0.05, P<0.01)，心肌纤维化面积明显增加(P<0.05)。与高盐组比较，预电针组收缩压、舒张压、平均动脉压和LVEDP、心脏质量比均降低(P<0.05，P<0.01)，左心室压+dP/dtmax和dP/dtmax绝对值均升高(P<0.05)，心肌组织ANP、MYH7、α-SMA及IL-1β、IL-6 mRNA表达均下调(P<0.05, P<0.01)，心肌纤维化面积明显减少(P<0.01)。结论：预电针可以降低高盐诱导的高血压大鼠血压，并改善心脏功能和心肌纤维化，其机制可能与抑制炎性反应有关。.
Keywords: Cardiac function; Hypertension; Inflammation; Myocardial fibrosis; Pre-electroacupuncture.