Effect of Acupuncture on the Genetic Expression of Myocardial Endothelin-1 and Atrial Natriuretic Peptide in Rats with Stress-Induced Prehypertension

Objective:To 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）.Methods:Thirty-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 3 rd,5 th,7 th,9 th,and 11 th day after modeling initiation.On the 12 th 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）.Results:SP was higher in the model group than the control group on the 3 rd ,5 th ,7 th ,9 th ,and11 th days（all P ＜.01）.SP in the model+AP group was lower than that in the control group on the 5 th and 7 th days（respectively,P=.008,P=.002） and on the 9 th and 11 th 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）.Conclusion:Acupuncture may lower blood pressure and down regulate the genetic expression of myocardial ET-1 and ANP in SIPH rats,suggesting a protective effect of acupuncture against myocardial damage.