Effect of acupuncture on the genetic expression of myocardial endothelin-1 and atrial natriuretic peptide in rats with stress-induced prehypertension

Abstract

ObjectiveTo explore the protective effect of acupuncture against myocardial injury in rats with stress-induced prehypertension (SIPH) by observing the genetic expression of myocardial endothelin-1 (ET-1) and atrial natriuretic peptide (ANP). MethodsThirty-six Wistar rats were randomized into three groups: the control group, model group, and model + acupuncture (AP) group (n = 12 rats per group). During the 11-day modeling period, the model group and the model + AP group experienced plantar electric stimulation in combination with noise exposure, and daily acupuncture intervention was applied simultaneously in the model + AP group; the control group did not experience modeling or acupuncture. Systolic pressure (SP) was measured the day before modeling began, and on the 3rd, 5th, 7th, 9th, and 11th day after modeling initiation. On the 12th day, histopathological observation of the left ventricle was made with hematoxylin-eosin staining and quantitative genetic expression of myocardial ET-1, and ANP was tested by quantitative real-time polymerase chain reaction (PCR). ResultsSP was higher in the model group than the control group on the 3rd, 5th, 7th, 9th, and 11th days (all P < .01). SP in the model + AP group was lower than that in the control group on the 5th and 7th days (respectively, P = .008, P = .002) and on the 9th and 11th days (P = .029, P = .039). Hematoxylin-eosin staining showed normal myocardial cellular structure in the control group. The model group showed disordered arrangement of cardiac cells with morphological changes in some nuclei, including enlargement or dissolution; there was also infiltration of inflammatory cells and proliferation of collagen fibers. In the model + AP group, most of the myocardial cells were normally structured, and only part of the cells had morphological changes with enlarged nuclei or dissolution. Real-time PCR showed that expression of ET-1 and ANP mRNA in the model group was greater than the control group (respectively, P = .024, P = .000101). The model + AP group had lower expression of ET-1 and ANP mRNA compared with the model group (respectively, P = .033, P = .043). ConclusionAcupuncture may lower blood pressure and downregulate the genetic expression of myocardial ET-1 and ANP in SIPH rats, suggesting a protective effect of acupuncture against myocardial damage.