Abstract:Objective To investigate whether the effect of puerarin on right ventricle hypertrophy of pulmonary hypertensive rats induced by chronic hypoxia-hypercapnia was related to new peptide Apelin or its receptor(APJ).Methods Thirty male Sprague-Dawley rats were randomly divided into three groups, they are control group,hypoxia-hypercapnia 4-week model group,and hypoxia-hypercapnia 4-week plus puerarin group.The concentrations of Apelin-36 protein in plasma and homogenate of right ventricular muscle were detected by radioimmunoassay.The mRNA expressions of Apelin and APJ in right ventricu- lar muscle were measured by semi-quantitive reverse transcription polymerase chain reaction(RT-PCR). Results The weight ratio of right ventricle to left ventricle plus septum[RV/(LV+S)] in model group was significantly higher than that in control group(p<0.01),but much lower in puerarin group than that in model group(p<0.01).The mean pulmonary arterial pressure(mPAP)in model group was markedly higher than that in control group(p<0.01),but much lower in puerarin group than that in model group (p<0.05).There was no difference of mean carotid pressure(mCAP)(p<0.05).The plasma concen- tration of Apelin-36 protein in model group was significantly higher than that in control group(p<0.01), and obviously higher in puerarin group than that in model group(p<0.05).The concentration of Apelin- 36 protein in right ventricular muscle in model group was increased as compared with that in control group (p<0.05),and obviously higher in puerarin group than that in model group(p<0.01).The expression of Apelin mRNA in right ventricle in model group was markedly lower than that in control group(p<0.05),but significantly higher in puerarin group than that in model group(p<0.01).The expression of APJ mRNA in right ventricle was lower than that in control group(p<0.05),but higher in puerarin group than that in model group(p<0.05).Conclusion The mechanisms of puerarin in decreasing pul- monary hypertension and inhibiting right ventricle hypertrophy in rats chronically exposed to hypoxia-hy- percapnia are partly associated with regulating Apelin/APJ system.