摘要
本文旨在探讨线粒体ATP敏感钾(mitochondrial ATP-sensitive K+,MitoKATP)通道对大鼠肺动脉平滑肌细胞低氧诱导因子-1α(hypoxia inducible factor-1α,HIF-1α)表达和细胞增殖的影响。原代培养大鼠肺动脉平滑肌细胞,分为常氧对照组、常氧+diazoxide(MitoKATP通道的选择性开放剂)组、常氧+5-hydroxydecanoate(5-HD,MitoKATP通道的选择性阻断剂)组、低氧对照组、低氧+diazoxide组、低氧+5-HD组,共6组,分别应用罗丹明123荧光技术检测各组大鼠肺动脉平滑肌细胞的线粒体膜电位,免疫组化检测HIF-1α的表达及酶联免疫检测仪检测细胞增殖的变化。结果显示,常氧+ diazoxide组与常氧对照组比较,罗丹明123荧光、HIF-1α表达及细胞增殖明显增强(P<0．05);低氧+diazoxide组与低氧对照组比较,罗丹明123荧光、HIF-1α表达及细胞增殖明显增强(P<0.05):常氧+5-HD组与常氧对照组比较,罗丹明123荧光、HIF-1α表达、细胞增殖没有明显变化(P>0．05);但低氧+5-HD组与低氧对照组比较,罗丹明123荧光明显减弱、HIF-1α表达及细胞增殖有所减弱(P<0．05)。结果提示:MitoKATP通道的开放能引起大鼠肺动脉平滑肌细胞线粒体膜去极化,并可以促进HIF-1α的表达及细胞增殖。
The objective of this paper was to investigate the effect of mitochondrial ATP-sensitive K^＋ （MitOKATP） channels on the expression of hypoxia inducible factor-1 α （HIF-1 α） and cell proliferation in pulmonary arterial smooth muscle cells （PASMCs） of rats. Cultured PASMCs were divided into six groups as follows： （1） normoxia group： cultured under normoxia for 24 h; （2） normoxia ＋ diazoxide group： cultured under normoxia with diazoxide, an opener of MitOKATe channel, for 24 h; （3） normoxia ＋ 5-HD group： cultured under normoxia with 5-hydroxydecanoate （5-HD）, an antagonist of MitOKATTP channel, for 24 h; （4） hypoxia group： cultured under hypoxia （37℃, 5% 02, 5% CO2, 90% N2） for 24 h; （5） hypoxia ＋ diazoxide group： cultured under hypoxia （37 ℃, 5% O2, 5% CO2, 90% N2） with diazoxide for 24 h; （6） hypoxia ＋ 5-HD group： cultured under hypoxia （37 ℃, 5% 02, 5% CO2, 90% N2） with 5-HD for 24 ho The relative changes in mitochondrial potential were tested with Rhodamine 123 （R-123） fluorescence technique. Immunohistochemical method was used to trace the expression of HIF- 1α. The proliferation of PASMCs was examined by MTT colorimetric assay. The results were as follows： The intensity of R-123 fluorescence in normoxia ＋ diazoxide group was significantly increased as compared with that in normoxia group （P〈0.05）, and the intensity of R-123 fluorescence in hypoxia ＋ diazoxide group was also significantly increased as compared with that in hypoxia group （P〈0.05）. 24-hour hypoxia or 24-hour hypoxia ＋ diazoxide markedly increased the intensity of R-123 fluorescence in PASMCs as compared with normoxia （P〈0.05）, and the change was more prominant in hypoxia ＋ diazoxide group than that in hypoxia group （P〈0.05）. There was no significant difference in the intensity of R-123 fluorescence between normoxia group and normoxia ＋ 5-HD group （P〉0.05）. However, 5-HD weakened the effect of 24-hour hypoxia on the intensity of R-123 fluorescence. The intensity of R-123 fluorescence in hypoxia ＋ 5-HD group was significantly decreased as compared with that in hypoxia group （P〈 0.05）. After exposure to hypoxia or hypoxia ＋ diazoxide for 24 h, the expression of HIF-1α and the proliferation of PASMCs were significantly increased as compared with that in normoxia or normoxia ＋ diazoxide group （P〈0.05）, and the change was more significant in hypoxia ＋ diazoxide group than that in hypoxia group （P〈0.05）. There was no significant difference in the expression of HIF-1α and the proliferation of PASMCs between normoxia group and normoxia ＋ 5-HD group （P〉0.05）. However, the expression of HIF-1α and the proliferation of PASMCs in hypoxia ＋ 5-HD group were significantly decreased as compared with that in hypoxia group （P〈0.05）. All these results suggest that the opening of MitoKATP channels followed by a depolarization of mitochondrial membrane might contribute to the increase of the expression of HIF-1α and the proliferation of PASMCs. This might be a mechanism of the development of hypoxic pulmonary hypertension.
出处
《生理学报》
CAS
CSCD
北大核心
2007年第2期157-162,共6页
Acta Physiologica Sinica
基金
This work was supported by the National Natural Science Foundation of China (No. 30370623).
关键词
低氧
低氧诱导因子-1Α
线粒体膜电位
平滑肌
hypoxia
hypoxia inducible factor-1α
mitochondrial membrane potential
smooth muscle
