低氧性肺动脉高压大鼠肺小动脉Siah1的表达变化及意义

Siah1 Expression and Its Significance in Pulmonary Arterioles of Rats with Hypoxic Pulmonary Hypertension

目的:探讨低氧性肺动脉高压(HPH)大鼠肺小动脉Siah1的动态表达变化及作用。方法:40只成年雄性Wistar大鼠随机分为对照组和低氧3d、7d、14d、21d组,每组8只,常压间断低氧复制HPH大鼠模型。测各组大鼠平均肺动脉压(mPAP)、右心室肥大指数(RVHI)、血管形态学指标;原位杂交、RT-PCR检测肺内Siah1mRNA表达,免疫组化、Westernblot检测其蛋白质水平。结果:①低氧7d后,肺小动脉出现血管重塑,且mPAP明显上升;低氧14d后,肺小动脉重塑更明显,mPAP达高峰。RVHI在低氧14d后明显增加。②Siah1mRNA在对照组肺小动脉壁呈弱阳性表达,低氧7d后显著增高,低氧14d后达高峰,低氧21d后下降但仍高于对照组。免疫组化显示,Siah1蛋白在对照组肺小动脉壁呈弱阳性表达,低氧7d后显著增高,低氧14d后达高峰,低氧21d后下降但仍高于对照组。③大鼠肺小动脉壁Siah1蛋白与Siah1mRNA呈正相关;Siah1mRNA、Siah1蛋白与mPAP、重塑指数、RVHI均呈正相关。结论:慢性低氧诱导肺小动脉壁Siah1表达增加,进而在HPH发病过程中发挥一定的作用。

Objective： To investigate the dynamic expression and effect of Siahl in the pulmonary arterioles in different phases of rats with hypoxic pulmonary hypertension （HPH）. Methods： Forty adult male Wistar rats were randomly divided into 5 groups, 8 rats in each group, and exposed to normoxia （Control group） or exposed to hypoxia for 3, 7, 14 or 21d, respectively. The HPH models were established by normobaric intermittent hypoxia. Mean pulmonary arterial pressure （mPAP）, right ventricle hypertrophy index （RVHI）, and vessel morphometry were measured. Reverse transcriptase-polymerase chain reaction （RT-PCR） and in situ hybridization were used to determine the mRNA expression of Siahl. Immunohistochemistry and Western blot were used to determine the protein expression of Siahl. Results： The hypoxic rats developed pulmonary vascular remodeling in pulmonary arterioles after 7 d of hypoxia. Pulmonary vascular remodeling in pulmonary arterioles was significantly increased after 14 d of hypoxia. The level of mPAP in hypoxic rats was increased significantly after 7 d of hypoxia, and reached to its peak after 14 d of hypoxic exposure. RVHI was markedly increased after 14 d of hypoxia. Siahl mRNA and protein staining were poor in pulmonary arteriole wails of the control rats, but were markedly increased after 7 and 14 d of hypoxia, then declined a little after 21 d of hypoxia. Linear correlation analysis showed that Siahl protein was positively correlated with Siah1 mRNA. Siahl mRNA and Siahl protein were positively correlated with mPAP, pulmonary vascular remodeling index and RVHI. Conclusion： Under chronic hypoxia, Siah1 is transcriptionally induced in pulmonary arterioles, and may be involved in the pathogenesis of HPH in rat.