[Involvement of ET-1/eNOS in the ameliorating effect of electroacupuncture on cardiac dysfunction in rats with spontaneously hypertensive]

Zhongguo Zhen Jiu. 2022 Jun 12;42(6):647-53. doi: 10.13703/j.0255-2930.20211228-k0006.
[Article in Chinese]

Abstract
in English, Chinese

Objective: To observe the effect of electroacupuncture (EA) at "Neiguan" (PC 6) on cardiac function of ventriculus sinister in rats with spontaneously hypertensive (SHR), and to explore the mediation effect of endothelin-1 (ET-1)/endothelial nitric oxide synthase (eNOS).

Methods: Six 12-week-old male Wistar Kyoto (WKY) rats were taken as the normal group. Eighteen 12-week-old SHR were randomly divided into a model group, an EA group and a sham EA group, 6 rats in each group. The rats in the EA group were treated with EA (disperse-dense wave, 2 Hz/15 Hz in frequency, 1 mA in current intensity) at "Neiguan" (PC 6), 30 min each time, once a day for 8 weeks. The rats in the sham EA group were treated with superficial needling at "Neiguan" (PC 6) with no electrical stimulation applied. After treatment, the left ventricular ejection fraction (LVEF) and left ventricular fractional shortening (LVFS) were tested by echocardiographic analysis. The left ventricular systolic pressure (LVSP), left ventricular end-diastolic pressure (LVEDP), heart rate (HR), the maximum rate of increase/decrease of left ventricular pressure (±dp/dtmax) were detected. The serum content of ET-1 was detected by ELISA. Western blot was used to evaluate the expression of ETAR, eNOS in myocardial tissue of left ventricular.

Results: Compared with the normal group, LVEF, LVFS, +dp/dtmax/LVSP and -dp/dtmax/LVSP were decreased (P<0.01, P<0.05), while LVSP, LVEDP, +dp/dtmax and -dp/dtmax were increased (P<0.01) in the model group. Compared with the model group, LVEF, LVFS, +dp/dtmax/LVSP and -dp/dtmax/LVSP were increased (P<0.01, P<0.05), and LVSP and LVEDP were decreased (P<0.01) in the EA group. Compared with the normal group, the serum content of ET-1 and the expression of ETAR in myocardial tissue were increased (P<0.01), whereas expression of eNOS was decreased (P<0.01) in the model group. Compared with the model group, the serum content of ET-1 and the expression of ETAR in myocardial tissue were decreased (P<0.05), whereas expression of eNOS was increased (P<0.05) in the EA group.

Conclusion: EA intervention may alleviate hypertensive cardiac function damage by up-regulating the expression of eNOS protein in myocardial tissue, down-regulating the serum content of ET-1 and the expression of ETAR protein in myocardial tissue.

目的：观察电针“内关”对自发性高血压大鼠（SHR）左心室功能的影响，并初步探究内皮素-１（ET-1）/ 内皮型一氧化氮合酶（eNOS）的介导作用。方法：选用12周龄雄性京都Wistar（WKY）大鼠6只为正常组；另选12周龄SHR 18只，随机分为模型组、电针组和假电针组，每组6只。电针组选取“内关”进行干预（疏密波，2 Hz/15 Hz，1 mA，持续30 min），每日1次，共8周。假电针组仅于“内关”浅刺，不予电刺激。电针干预结束后，采用超声心动图检测各组大鼠左心室射血分数（LVEF）、左心室短轴缩短率（LVFS），采用右侧颈总动脉插管检测各组大鼠左心室收缩压（LVSP）、左心室舒张期末压（LVEDP）、心率（HR）、左心室内压最大上升速率（+dp/dtmax）、左心室内压最大下降速率（-dp/dtmax）；采用ELISA法检测各组大鼠血清ET-1含量，Western blot法检测各组大鼠左心室心肌组织内皮素受体A（ETAR）、eNOS蛋白表达情况。结果：与正常组比较，模型组大鼠LVEF、LVFS、+dp/dtmax/LVSP、-dp/dtmax/LVSP均降低（P<0.01，P<0.05）；LVSP、LVEDP、+dp/dtmax、-dp/dtmax均升高（P<0.01）。与模型组比较，电针组LVEF、LVFS、+dp/dtmax/LVSP、-dp/dtmax/LVSP均升高（P<0.01，P<0.05）；LVSP、LVEDP均降低（P<0.01）。与正常组比较，模型组血清ET-1含量、心肌组织ETAR蛋白表达均升高（P<0.01），eNOS蛋白表达降低（P<0.01）；与模型组比较，电针组血清ET-1含量、心肌组织ETAR蛋白表达均降低（P<0.05），eNOS蛋白表达升高（P<0.05）。结论：电针干预可能是通过上调心肌组织eNOS蛋白表达，下调血清ET-1含量、心肌组织ETAR蛋白表达实现对高血压性心功能损害的缓解作用。.

Keywords: electroacupuncture; endothelial nitric oxide synthase (eNOS); endothelin-1 (ET-1); essential hypertension; left ventricular function.

MeSH terms

  • Animals
  • Electroacupuncture*
  • Endothelin-1 / genetics
  • Heart Diseases*
  • Hypertension* / therapy
  • Male
  • Nitric Oxide Synthase Type III / genetics
  • Rats
  • Rats, Inbred SHR
  • Rats, Inbred WKY
  • Stroke Volume
  • Ventricular Function, Left

Substances

  • Endothelin-1
  • Nitric Oxide Synthase Type III