The experimental study of correlation between the circulating endothelial progenitor cells and serum nitric oxide in rat model of pulmonary hypertension

Objective The present study was designed to investigate the change of circulating endothelial progenitor cells(EPC) and its relationship with the change of serum nitric oxide(NO) in rat model of pulmonary hypertension(PH).Methods The rat was injected with crotaline to induce model of PH,the number of peripheral circulating EPC was detected by flow cytometry,which is characterized by negative of CD45,double positive of CD34/FLK-1.The serum concentration of NO was assessed by Greiss method.The relationship of them was analyzed by simple linear regression.Meanwhile,the output of EPC,the expression of CD34 and Flk-1 were assessed when peripheral mononuclear cells cultured in vitro.Results The number of peripheral circulating EPC in PH group was lower than it in control group[(0.016±0.007)% vs.(0.031±0.011)%,t=3.144,P0.01].The serum concentration of NO in PH group was lower than it in control group too [(19.66±2.78)μmol/L vs.(54.31±3.81)μmol/L,t=20.784,P0.01].In PH group the number of circulating EPC was positively correlated with the level of nitricoxide(r=0.792,P0.05).Furthermore the number of EPC and the expression of CD34 and Flk-1 were down-regulated in PH model group than in control group when cultured in vitro.Conclusions The occurrence of PH may be associated with the down-regulation of circulating EPC,which induced by the decrease of serum concentration of NO.