Effects Of Cigarette Smoke Exposure On Expression Of ENOS And NO In Pulmonary Vascular Of Rats

Objective To explore the effects of cigarette smoke exposure on pulmonary artery pressure and expressional levels of eNOS and NO of pulmonary vascular in rats.Methods twenty-eight male SD rats were divided randomly into control group(C group), smoke exposure1month group(Slm group),smoke exposure2months groug(S2m group)and smoke exposure3months group(S3m group)with7rats in each group. Right ventricular systolic pressure (RVSP) and right ventricular hypertrophy index (RVHI) were observed. Nitrate reductase enzymatic was employed to detect the expression of nitric oxide (NO) in lung tissue. The expression of endothelium nitric oxide synthase(eNOS) protein in pulmonary vascular was measured by immunohistochemistry.Results①The mRVSP and RVHI in S3m group (65.63±0.93,54.79±7.13) were significantly higher than those in C group (16.85±1.26,36.62±1.32), S1m group (23.57±14.5137.38±0.73)and S2m group (24.07±4.18,32.41±0.26)(P<0.01, respectively). There were no statistically difference in mRVSP and RVHI in Group C, S1m group and S2m group (P>0.05).②The eNOS protein expression of pulmonary vascular in S1m group, S2m group and S3m group (0.32±0.04,0.31±0.03,0.24±0.03) were lower than that in group C (0.43±0.06)(P<0.01,respectively).And which in S3m group was lower than in S1m group and S2m group (P<0.05). There were no statistically difference in the eNOS protein expression of pulmonary vascular between S1m group and S2m group (Pp>0.05).③The expression of lung tissue NO in S1m group, S2m group and S3m group(1.98±0.20,1.54±0.09,0.95±0.09) were lower than in group C (2.98±0.19){P<0.01, respectively),and which in S3m group was less than in S1m group and S2m group (P<0.01). There were no statistically difference in the expression of lung tissue NO between S1m group and S2m group (P>0.05).④mRVSP was positively correlated with RVHI (r=0.713, P<0.01). NO in lung tissue was negatively correlated with mRVSP(r=-0.615, P<0.05). eNOS in pulmonary vascular was positively associated with No in lung tissue (r=0.944,P<0.01)..Conclusions By down-regulating the expression of eNOS protein in endothelial cell of pulmonary vascular, cigarette smoke exposure induce the biosynthesis of NO,which induce the increasing of pulmonary artery pressure, and the effect is time dependence in certain scope.