HuoXue QianYang QuTan Recipe attenuates left ventricular hypertrophy in obese hypertensive rats by improving mitochondrial function through SIRT1/PGC-1α deacetylation pathway

Abstract

Mitochondrial dysfunction plays a vital role in the progression of left ventricular hypertrophy (LVH). Previous studies have confirmed that the disorder of SIRT1/PGC-1α deacetylation pathway aggravated mitochondrial dysfunction. HuoXue QianYang QuTan Recipe (HQQR) is a commonly used prescription that has shown therapeutic effects on obesity hypertension and its complications. However, the potential mechanisms are still unclear. In the present study, obesity hypertension (OBH) was established in rats and we investigated the efficacy and mechanisms of HQQR on LVH. Rats were divided into the five groups: (1) WKY-ND group, (2) SHR-ND group, (3) OBH-HF group, (4) OBH-HF/V group and (5) OBH-HF/H group. We evaluated body weight, Lee index and blood pressure (BP) before and every 2 weeks after treatment. After 10 weeks of treatment, we mainly detected glycolipid metabolic index, the severity of LVH, mitochondrial function along with SIRT1/PGC-1α deacetylation pathway. Our results showed that HQQR significantly lowered body weight, Lee index, BP and improved the disorder of glycolipid metabolism in OBH rats. Importantly, we uncovered HQQR could alleviate mitochondrial dysfunction in OBH rats by regulating SIRT1/PGC-1α deacetylation pathway. These changes could be associated with the inhibition of LVH.

Keywords: HuoXue QianYang QuTan Recipe; Left ventricular hypertrophy; Mitochondrial function; Obesity hypertension; SIRT1/PGC-1α deacetylation.

Figure 1. HQQR lowered body weight, Lee index, BP and improved glycolipid metabolism disorder in OBH rats

(A–D) Body weight, Lee index and BP were measured before and every 2 weeks after treatment (n = 10–12 per group). (E) The level of lipid metabolism was assayed by automatic biochemical analyzer (n = 6 per group). (F) The level of glucose metabolism was assayed by automatic biochemical analyzer and ELISA (n = 6 per group). Data are mean ± SD. *P < 0.05, **P < 0.01 compared with WKY-ND; ^#P < 0.05, ^##P < 0.01 compared with SHR-ND; ⁺P < 0.05, ⁺⁺P < 0.01 compared with OBH-HF; ^∧P < 0.05, ^∧∧P < 0.01 compared with OBH-HF/H.

Figure 2. HQQR alleviated LVH in OBH rats

(A) LVMI was calculated by left ventricle mass (mg)/body weight (g) (n = 6 per group). (B) Representative photomicrographs of HE staining; 400× magnification. (C) Representative photomicrographs of WGA staining; 400× magnification. (D) Quantification of cardiomyocyte cross-sectional area. (E) Real-time PCR analysis for the mRNA expression of ANP and β-MHC were performed. Relative fold change of ANP and β-MHC was presented in the graph (n = 6 per group). Data are mean ± SD. *P < 0.05, **P < 0.01 compared with WKY-ND; ^#P < 0.05, ^##P < 0.01 compared with SHR-ND; ⁺P < 0.05, ⁺⁺P < 0.01 compared with OBH-HF.

Figure 3. HQQR improved the morphology of mitochondria and inhibited oxidative stress damage

(A) Representative photomicrographs of transmission electron microscope; 8200× magnification. (B) The level of the Mn-SOD activity was assayed in each group (n = 4 per group). (C) The protein expression of COX1 and ATPase6 was determined by immunoblotting. (D) Western blot quantification of COX1 and ATPase6 levels (n = 4 per group). Data are mean ± SD. *P < 0.05, **P < 0.01 compared with WKY-ND; ⁺P < 0.05, ⁺⁺P < 0.01 compared with OBH-HF.

Figure 4. HQQR alleviated LVH and improved mitochondrial function by SIRT1/PGC-1α deacetylation pathway

(A) The ATP content was detected in each group (n = 4 per group). (B) The mtDNA copy number was assayed in each group (n = 4 per group). (C) The protein expression of SIRT1, PGC-1α, NRF1 and TFAM was determined by immunoblotting. (D) Western blot quantification of SIRT1, PGC-1α, NRF1 and TFAM levels (n = 4 per group). (E) Immunoprecipitation and Western blot analysis of PGC-1α acetylation in each group. (F) The ratio of acetylated PGC-1α to precipitated PGC-1α protein was calculated (n = 4 per group). Data are mean ± SD. *P < 0.05, **P < 0.01 compared with WKY-ND; ⁺P < 0.05, ⁺⁺P < 0.01 compared with OBH-HF.