Effects of electroacupuncture at Taichong (LR 3) and Baihui (DU 20) on cardiac hypertrophy in rats with spontaneous hypertension

OBJECTIVE

To investigate the effects of electroacupuncture (EA) at Taichong (LR 3) and Baihui (DU 20) on myocardial hypertrophy in spontaneously hypertensive rats (SHRs).

METHODS

Thirty-six SHRs were randomly assigned to model, EA, and Losartan groups, with twelve rats per group. Twelve Wistar Kyoto rats were selected as the normal control group. Systolic blood pressure (SBP) and cardiac function were measured in all rats. Expression levels of factors associated with the phosphoinositide 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/Akt/mTOR) pathway were evaluated by Western blotting and real-time PCR. Pathological changes of the heart tissue were observed by hematoxylin-eosin staining.

RESULTS

After treatment, enhanced SBP was significantly decreased in the EA and Losartan groups compared with the model group (P < 0.01). Echocardiographic and morphological analyses revealed that enhanced end-diastolic interventricular septal thickness and left ventricular posterior wall thickness, as well as ratio of left ventricular weight to body weight were markedly diminished in the EA and Losartan groups (P < 0.01 or P < 0.05), while reduced left ventricular end-diastolic dimension and left ventricular ejection fraction were significantly ameliorated (P < 0.01). Real-time PCR and western blotting analyses showed that the expression levels of PI3K, Akt, and mTOR in SHRs were significantly up-regulated by EA and Losartan (P < 0.01), while the expression levels of PTEN and ANP were down-regulated (P < 0.01).

CONCLUSION

EA at Taichong (LR 3) and Baihui (DU 20) inhibited the development of cardiac hypertrophy and improved the cardiac function in SHRs, possibly through regulation of the PI3K/Akt/mTOR signalling pathway.

Effect of Taichong (LR 3) acupuncture in spontaneously hypertensive rats

OBJECTIVE

To evaluate the effects of Taichong (LR 3) acupuncture points (acupoints) on the expression of glucose transporter protein 1 (GLUT1) in the hypothalamus of spontaneously hypertensive rats (SHRs) as measured by combined positron emission tomography and computed tomography (PET-CT).

METHODS

Spontaneously hypertensive rats (SHR) were divided into model, Taichong (LR 3) acupuncture, and sham groups. Additionally, Tokyo Wistar rats were used as the control group. Changes in blood pressure were recorded in different groups of rats before and after the corresponding treatment. Hematoxylin and eosin (HE) staining was used to study basic morphological changes, and immunohistochemistry was used to determine GLUT1 expression in the hypothalamus. Further, PET-CT was utilized to elucidate the antihypertensive mechanism after acupuncture at the Taichong (LR 3) acupoints.

RESULTS

PET-CT indicated activation of the hypothalamus. Measurement of blood pressure showed that acupuncture at the Taichong (LR 3) acupoints lowered blood pressure. HE staining did not show any significant pathological changes, although differences in cell number were observed. Immunohistochemical analysis indicated a GLUT1 downregulation in the SHRs of the Taichong (LR 3) acupuncture group after the treatment.

CONCLUSION

Acupuncture at Taichong (LR 3) acupoints lowered blood pressure in SHRs, with possible mechanisms being changes in cell number and GLUT1 expression in the hypothalamus.

Tangnaikang improves insulin resistance and β-cell apoptosis by ameliorating metabolic inflammation in SHR.Cg-Leprcp/NDmcr rats

OBJECTIVE

To investigate the effects of Tangnaikang (TNK), a mixture of five herbal plant extracts, on inflammation-mediated insulin resistance and B-cell apoptosis in SHR.Cg-Leprcp/NDmcr (SHR-cp) rats.

METHODS

Seven-week-old SHR-cp rats were randomly divided into a control (CON) group and a TNK (3.24 g/kg) group. Wistar-Kyoto rats at the same age were used as the normal control group. After 7 weeks of continuous intragastric administration of TNK, the glucose metabolic status and insulin sensitivity of the rats were evaluated by assessing fasting serum glucose (FBG), the oral glucose tolerance test (OGTT), fasting serum insulin (FINS), and the insulin sensitivity index (ISI). Serum tumor necrosis factor-a (TNF-a), interleukin-6 (IL-6), C-reactive protein (CRP) and adiponectin were measured via enzyme-linked immunosorbent assays. Macrophage infiltration and apoptosis in adipose tissues were detected through F4/80 immunohistochemistry and the terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay. Islet morphology and B-cell apoptosis were investigated using double immunofluorescence staining and the TUNEL assay. The expression of cytokine genes in adipose tissue, the liver, and the pancreas was detected in real-time polymerase chain reaction assays. The expression and phosphorylation levels of insulin signaling-, inflammation-, and B-cell survival-related proteins in the liver and pancreas of SHR-cp rats were detected by western blotting.

RESULTS

TNK (3.24 g/kg) treatment significantly decreased body weight, FBG and FINS; improved impaired glucose tolerance; increased the ISI; reduced serum levels of TNF-a, CRP and IL-6; and increased serum adiponectin. The mRNA expression of inflammatory markers was markedly reduced in the liver, pancreas, and adipose tissue. F4/80- and TUNEL-positive cells in adipose tissues were decreased, as was the number of TUNEL-positive B-cells. The phosphorylation of c-Jun N-terminal kinase and that of insulin receptor substrate-1 at serines 307 and 1101 was significantly decreased. In the pancreas, the expression of nuclear factor kappa-light chain-enhancer of activated B cells-p65 was significantly decreased, and phosphoinositide 3-kinase and IRS-2 were significantly increased.

CONCLUSION

TNK was able to improve insulin resistance and B-cell apoptosis in SHR-cp rats, which might be associated with its ability to relieve the overall and local metabolic inflammatory responses observed in SHR-cp rats.