Sympathoinhibitory electroacupuncture (EA) interacts positively with anti-inflammatory EA alleviating blood pressure in hypertensive rats

Figure 1. Dynamic or weekly changes of systolic blood pressure (SBP, panel A) and diastolic blood pressure (DBP, panel B) in the Dahl salt-sensitive hypertensive (DSSH) rats treated with repetitive electroacupuncture (EA) and in DSS normotensive (NTN) rats. The BPs at week 5 were defined as pre-EA levels in the 4 groups of rats treated with EA regimens. The 4 EA regimens include sympathoinhibitory EA (SI-EA), anti-inflammatory EA (AI-EA), combined SI-EA and AI-EA (cEA), and sham-EA. Data are expressed as mean ± SE. §, P < 0.05, post-sham EA vs. pre-sham EA; †, P < 0.05, post-SI-EA vs. pre-SI-EA; *, P < 0.05, post-cEA vs. pre-cEA. Note: BP data were recorded twice per week from −2 to 0 week (see Supplementary Material).

Figure 2. Bar histograms showing systolic blood pressure (SBP, panel A) and diastolic blood pressure (DBP, panel B) at end of week 10 in rats treated with cEA, SI-EA, AI-EA and sham-EA. #, P < 0.05, active EA vs. sham-EA; *, P < 0.05, cEA or SI-EA vs. AI-EA; and **, P < 0.05, cEA vs. SI-EA.

Figure 3. Plasma biomarker concentrations are increased in the Dahl salt-sensitive hypertensive rats treated with sham electroacupuncture (Sham-EA) compared to normotensive (NTN) rats. Plasma norepinephrine (NE) (A) is reduced in cEA and SI-EA treated rats compared to Sham-EA rats. Inflammatory biomarkers (hs-CRP (B) and IL-6 (C) are reduced in each EA treated (SI-EA, AI-EA, and cEA) groups of rats compared to Sham-EA rats. Data are expressed as mean ± SE. #, P < 0.05, each group compared to sham-EA; *, P < 0.05 AI-EA vs. cEA; **, P < 0.05, SI-EA vs. cEA.

Figure 4. Schematic diagram summarizes the effects of electroacupuncture (EA) on hypertension and their potential underlying mechanisms. Anti-inflammatory EA (AI-EA) treatment slows down the advancement of high blood pressure primarily through the alleviation of chronic inflammation. On the other hand, Sympathoinhibitory EA (SI-EA) significantly lowers blood pressure by inhibiting sympathetic activity. Meanwhile, combining EA (cEA) treatment demonstrates a more substantial reduction in hypertension by modulating the intricate interplay between elevated sympathetic activity and inflammatory mediators. (−), decrease; (+), increase. NE, norepinephrine; hs-CRP, high sensitive C-reactive protein, and IL-6, interleukin 6.

Figure 5. Timeline and group assignments of the current study. Timeline of experiments shown in (A). Dahl salt-sensitive (DSS) hypertensive rats were randomly allocated into SI-EA, AI-EA, cEA, or Sham-EA groups following a 2 × 2 factorial design. These rats were fed with 4% NaCl (high salt) diet for 10 weeks to develop hypertension. They were treated with repetitive EA or Sham-EA for 30 min twice weekly for five weeks once the blood pressures (BP) of these rats reached moderate hypertensive range. Blood pressures were evaluated by tail-cuff weekly in all 5 groups of rats. One of the 5 groups of DSS rats was fed with standard rat chow and their BP remained in normotensive range. At the end of the experiment, plasma samples were collected from the heart of each rat under anesthesia. (B) displaying flow diagram of rats assigned to different EA regimen groups.