【摘要】 目的:为揭示缺氧性肺血管收缩机制,探讨细胞外信号调节激酶1/2(ERK1/2)是否参与15-羟基二十碳四烯酸(15-HETE)收缩缺氧大鼠肺动脉的过程以及15-HETE对ERK1/2活性的影响。方法:将大鼠置于氧气分数为12.0%的低氧箱中连续9 d形成缺氧模型。完整取出心肺,在显微镜下分离直径0.8-1.0 mm肺动脉剪为3 mm长的动脉环在组织浴槽内进行张力研究。比较15-HETE给药前后肺动脉环张力变化;用ERK1/2上游激酶抑制剂U0126孵育肺动脉环,比较U0126孵育前后15-HETE对缺氧性肺动脉环的收缩作用;机械法去除动脉环内皮,再比较U0126孵育前后15-HETE的收缩作用。酶法分离培养大鼠肺动脉平滑肌细胞。W estern b lotting方法检测15-HETE作用时间(5-90 m in)及浓度(10-9-10-6mol/L)对ERK1/2的表达及活性的影响。结果:15-HETE对缺氧大鼠肺动脉环有收缩作用,呈浓度-效应关系,与正常对照组比较差异显著(P<0.05);内皮完整和内皮去除的肺动脉环,U0126孵育前后,15-HETE的缩血管作用都受到抑制,差异显著(均为P<0.05)。W estern b lo-ting结果显示,15-HETE明显增强肺动脉血管平滑肌细胞ERK1/2的活性,随时间延长而降低,随浓度增加而增加,但对ERK1/2的蛋白表达无影响。结论:15-HETE能上调大鼠肺动脉血管平滑肌细胞ERK1/2的活性,提示ERK1/2的活化是15-HETE收缩慢性缺氧大鼠肺动脉的一个重要环节。更多还原

【Abstract】 AIM: The aim of the present study was to investigate whether the extracellular signal regulated kinase-1/2（ERK1/2） pathway was involved in 15-hydroxyeicosatetraenoic acid（15-HETE）-induced chronic hypoxic pulmonary artery（PA） constriction and whether ERK1/2 activity was influenced by 15-HETE,for clarifying the mechanism of hypoxic pulmonary vasoconstriction （HPV）.METHODS: Rats were placed in hypoxic box with fractional inspired oxygen（FiO₂） 0.12 for 9 days to make hypoxic models,while those lived in FiO₂ 0.21 served as normal controls.Heart and lungs were taken out from chest and PA in diameter of 1-1.5 mm was isolated and cut into rings with 3 mm long for tension studies in organ baths.The ring tensions before and after adding 15-HETE were compared.Influences of ERK1/2 upstream kinase inhibitor U0126 as well as endothelium integrity on 15-HETE-induced HPV were observed.Expression and activity of ERK1/2 in cultured rat pulmonary artery smooth muscle cells（PASMCs） treated with 15-HETE for different times and concentrations were examined by Western blotting.RESULTS: 15-HETE significantly constricted PA rings from hypoxic rats,and the response of the hypoxic rings were significantly greater than that of normoxic ones（P<0.05）.U0126 significantly reduced vasoconstriction induced by 15-HETE both in endothelium-intact and-denuded rings（both were P<0.05）.Western blotting results showed 15-HETE enhanced activity of ERK1/2 in PASMCs,increasing with concentration and decreasing with time.CONCLUSION: 15-HETE upregulates activity of ERK1/2 in PASMCs of rats.The activation of ERK1/2 is an important step in 15-HETE-induced HPV in rats.更多还原