低氧致肺动脉高压新生大鼠TRIP6和cyclinD1表达及其对肺血管重塑的影响

目的：研究低氧致新生鼠缺氧性肺动脉高压( hypoxia induced pulmonary hypertension, HPH)发生发展过程中,肺组织中TRIP6、cyclinD1蛋白动态变化,及其对肺血管重塑的影响。方法采用低氧方法(FiO20.10~0.12)制备新生SD大鼠HPH模型,对照组予正常氧浓度FiO20.21。每组32只于实验后14 d,监测右心室平均压力,采集心脏及肺组织标本,分别用BL420系统监测右心室压力,测定右心室肥厚指数及肺小动脉中膜面积百分比、肺小动脉中膜厚度百分比评估模型是否成功。同时每组大鼠分别于实验后3、7、10、14 d,采集肺组织标本,采用免疫组织化学及Western blot技术观察TRIP6和cyclinD1蛋白表达变化。结果与对照组比较,模型组14 d后,肺小动脉管壁增厚,管腔变狭窄,肺小动脉中膜面积百分比(42.28±1.64)％ vs.(24.12±0.83)％]、中膜厚度百分比(28.26±1.41)％vs.(16.94±0.90)％]、右心室肥厚指数(0.52±0.02 vs.0.29±0.01)、右心室平均压力(22.00±0.82)mmHg vs.(12.10±0.48)mmHg,1 mmHg＝0.133 kPa]均显著增加(P<0.01)；TRIP6在对照组14 d时肺小动脉管壁几乎无表达,模型组明显增强,其表达水平在3、7、10、14 d时明显增高( P<0.05)；cyclinD1蛋白表达水平在3 d时两组比较差异无统计学意义( P>0.05),7、10、14 d时明显高于对照组(P<0.05)；Pearson相关分析显示,14 d时肺组织TRIP6蛋白与cyclinD1蛋白表达呈明显正相关(r＝0.587,P<0.05),中膜厚度百分比、中膜面积百分比与肺组织TRIP6蛋白、cyclinD1蛋白表达均呈明显正相关(r＝0.878,P<0.01；r＝0.812,P<0.01；r＝0.872,P<0.01；r＝0.789,P<0.01)。结论在HPH发生中,肺组织中TRIP6蛋白和cyclinD1表达上调,并且增加的TRIP6和cyclinD1蛋白表达可能与肺血管重塑相关,进而影响肺动脉高压的发生发展过程。

Effects of TRIP6 and cyclinD1 on hypoxia induced pulmonary vascular remodeling in newborn rats

Objective To explore the changes of TRIP6 and cyclinD1 protein expression levels in lung tissues of newborn rats with hypoxia induced pulmonary hypertension( HPH) and their effects on pulmo-nary vascular remodeling. Methods Hypoxia ( FiO2 0. 10-0. 12 ) was used to prepare the HPH model of newborn SD rats,and the control group was given normal oxygen concentration ( FiO2 0. 21 ) . After experi-ment 14 days,we monitored right ventricular pressure and collected heart and lung tissue samples. The right ventricular pressure, right ventricular hypertrophy index ( RVHI ) and the percentage of pulmonary artery medical thickness( WA%) ,the percentage of pulmonary artery medical area ( WT%) were detected to evalu-ate the HPH model. On day 3,7,10 and 14,8 rats were sacrificed and the lung tissue was removed. The expression of TRIP6 and cyclinD1 protein were detected by Western-blot and immunohistochemical staining. Results On day 14 of hypoxia exposure, WA% ( 42. 28 ± 1. 64 )% vs. ( 24. 12 ± 0. 83 )%] , WT%(28. 26 ± 1. 41)% vs. (16. 94 ± 0. 90)%],RVHI(0. 52 ± 0. 02 vs. 0. 29 ± 0. 01) and mean right ventricu-lar pressure(22. 00 ± 0. 82 mmHg vs. (12. 10 ± 0. 48) mmHg,1 mmHg =0. 133 kPa] in hypoxia group were significantly higher than those in control group ( P<0. 01 ) . The immunohistochemical staining results showed that after 14 days of hypoxia,the expression of TRIP6 protein was significantly increased in the pul-monary artery. Western blot results showed that,on day 3,7,10,14 of hypoxia exposure,the expression levels of TRIP6 protein were significantly higher than those of the control group (P<0. 05). There was no obvious difference in the expression of cyclinD1 protein between the hypoxia group and the control group on day 3. On day 7,10,14 of hypoxia exposure,the expression levels of cyclinD1 protein were significantly higher than those of the control group(P<0. 05). The Pearson correlation analysis indicated that WT% and WA% were positively correlated with the expression of TRIP6 and cyclinD1(r=0. 878,P<0. 01;r=0. 812,P<0. 01;r=0. 872,P<0. 01;r =0. 789, P <0. 01. The expression of TRIP6 was positively correlated with that of cyclinD1(r=0. 587,P<0. 05). Conclusion The upregulation of TRIP6 and cyclinD1 occurs in neonatal rats with HPH,which may be associated with the pulmonary vascular remodeling.