烟雾暴露大鼠肺血管内皮型一氧化氮合酶及一氧化氮的表达变化

Effects of cigarette smoke exposure on expression of eNOS and NO in pulmonary vascular of rats

目的探讨不同烟雾暴露量对大鼠肺动脉压及肺血管内皮型一氧化氮合酶（eNOS）和一氧化氮（NO）表达的影响。方法健康雄性SD大鼠21只，随机分为对照组（C组）、烟雾暴露1个月组（S1m组）、烟雾暴露3个月组（S3m组），建立大鼠被动吸烟模型。检测各组大鼠平均右心室收缩压（mRVSP）及右心室肥大指数（RVHI），硝酸还原酶法检测肺组织NO的表达，免疫组化法检测肺血管eNOs的表达。结果①S3m组mRVSP及RVHI[（65．63±0．93）mmHg，（54．79±7．13）％]高于S1iTI组[（23．57±14．51）mmHg，（36．62±1．32）％]与C组[（16．85±1．26）mmHg，（32．41±0．26）％]，差异均有统计学意义（P值均〈0．01），C组与Slm组差异无统计学意义（P〉0．05）；②slm组与S3m组肺血管内皮细胞eNOS蛋白（0．32±0．04，0．24±0．03）均低于c组（0．43±0．06），差异均有统计学意义（P值均〈0．01），S3m组低于Slm组，差异有统计学意义（P〈0．01）；③Slm组和S3m组肺组织NO[（1．98±0．20）／,mol／gprot，（0．95±0．09）μmol／gprot]均低于C组E（2．98±0．19）μmol／gprot2，差异均有统计学意义（P值均〈0．01），S3m组低于S1in组，差异有统计学意义（P〈0．01）；④mRVSP与RVHI呈正相关（r=0．713，P〈0．01），肺组织NO与mRVSP呈负相关（r=-0.615，P〈0．05），肺血管eNOS与肺组织NO呈正相关（r=0．944，P〈0．01）。结论烟雾暴露可能下调大鼠肺血管内皮细胞eNOS的表达，进而影响NO的合成，参与肺动脉压高压的形成，且该作用在一定范围内呈时间依赖性。

Objective To explore the effects of cigarette smoke exposure on pulmonary artery pressure and levels of endothelium nitric oxide synthase （eNOS） and nitric oxide （NO） of pulmonary vascular in rats. Methods Twenty-one male SD rats were divided randomly into control group （C group）, smoke exposure one month group （Slm group） and smoke exposure three months group （S3m group）, seven rats in each group. Mean right ventricular systolic pressure （mRVSP） and right ventricular hypertrophy index （RVHI） were observed. Nitrate reductase enzymatic was employed to detect the expression of NO in lung tissue. The expression of eNOS protein in pulmonary vascular was measured by immunohistoehemistry. Results （i） The mRVSP and RVHI in S3m group [（65.63 ± 0.93） mmHg, （ 54.79 ± 7.13 ） % ] were significantly higher than those in Slm group [ （23.57 ± 14.51 ） mmHg, （ 36.62 ± 1.32）%] andC group [（16.85±1.26） mmHg,（32.41±0.26）%] （all P 〈0.01）. There were no statistical difference in mRVSP and RVHI between C group and Slm group （ P 〉0. 05）. ②The eNOS protein expression of pulmonary vascular in Slm group and S3m group （0.32±0.04,0.24±0.03） were lower than that in group C （0.43±0.06） （all P 〈0.01） ,and that in S3m group was lower than that in Slm group （ P 〈0.01）. ③The NO expression of lung tissue in Slm group and S3m group[ （1.98± 0.20） μmol/gprot, （0. 95±0.09） μmol/gprot] was lower than that in group C [（2.98±0.19） μmol/gprot] （all P 〈0.01）,and that in S3m group was less than that in Slm group （P 〈0.01）. 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 induces the biosynthesis of NO,which induces the increase of pulmonary artery pressure, and the effect is time dependence in certain scope.