STAT3/NFAT信号通路对PH-LHF模型肺血管重构的作用及机制的研究

Pulmonary vascular remodeling is the key pathogenesis in the disease of pulmonary hypertension due to left heart failure (PH-LHF). Endothelin-1 and interleukin-6 have been recognized as precipitating factors in the progression of PH-LHF. The active signal transducers and activators of transcription 3 (STAT3)/ nuclear factor of activated T-cell(NFAT) pathway may be responsible for the imbalance of cell proliferation and apoptosis. Dehydroepiandrosterone (DHEA) inhibits the STAT3/NFAT activation in vascular smooth muscle cell and liver cells. We hypothesize that the involvement of STAT3/NFAT may play important role in the progression of PH-LHF and DHEA reverses pulmonary vascular remodeling through the inhibition of STAT3/NFAT axis. To test this hypothesis, this study will be conducted following aspects: (1) study the effect of endothelin-1 and interleukin-6 on the STAT3/NFAT pathway in pulmonary artery smooth muscle cells (PASMCs) and the intervention of DHEA; (2) investigate the effects and mechanisms of DHEA on the prevention and reservation of pulmonary vascular remodeling in a rat model of PH-LHF. Our study will improve understanding of the potential role of STAT3/NFAT pathway in the pathogenesis of PH-LHF and provide potential therapeutic targeting for PH-LHF.

肺血管重构是左心衰竭相关性肺动脉高压(pulmonary hypertension due to left heart failure , PH-LHF)发病机制的核心。内皮素-1及白介素-6是肺血管重构重要的诱导因子。信号转录子和转录激活子3（STAT3）/活化T细胞核因子（NFAT）信号通路过度激活参与细胞增殖与凋亡失平衡，推测其在PH-LHF肺血管重构中起重要作用。已知脱氢表雄酮（dehydroepiandrosterone, DHEA）可有效抑制肝细胞及外周血管平滑肌细胞STAT3/NFAT轴，推测其可能改善肺血管重构。本课题1.研究内皮素-1、白介素-6激活肺动脉平滑肌细胞STAT3/NFAT轴导致增殖与凋亡失平衡的作用机制及DHEA干预作用；2.构建 PH-LHF模型，观察DHEA对STAT3/NFAT信号通路及肺血管重构的影响。本研究将阐明PH-LHF发病新机制和治疗新策略。

背景：.目前左心衰竭相关性肺动脉高压（PH-LHF）缺乏安全、有效的治疗方案。信号转录子和转录激活子 3（STAT3）信号通路包括RhoA/Rho激酶与血管平滑肌的增殖、迁移、收缩等有关。有研究提示阿托伐他汀、脱氢表雄酮（DHEA）可分别抑制Rho激酶与STAT3信号通路。本研究通过建立大鼠主动脉缩窄所致PH-LHF模型，研究阿托伐他汀或DHEA治疗PH-LHF的作用与机制。..方法：.实验动物随机分为4组，假手术组、模型组、阿托伐他汀或DHEA预防组、以及阿托伐他汀或DHEA逆转组。阿托伐他汀或DHEA预防组分别于术后予阿托伐他汀（10mg/kg/day）或DHEA(15 mg/kg/day)治疗至63天，阿托伐他汀或DHEA逆转组于第50-63天予同剂量阿托伐他汀或DHEA治疗。右室占总体重比值（RV/BW）评估右室肥厚，右肺中叶湿/干重比评估肺水肿，右心导管测肺动脉平均压力，心脏彩超评估心脏结构与功能。利用HE染色、免疫组化、PCNA、TUNEL等检测，对肺小血管重构、增殖及凋亡水平、炎症浸润等进行分析。应用蛋白印记技术，检测STAT3信号通路因子的表达。..结果：.阿托伐他汀研究结果：与假手术组比较，模型组肺动脉平均压(32.82±6.96mmHg vs 10.53±3.52mmHg）显著增高； RV/BW明显升高；右肺中叶的湿/干重比显著增高；肺小动脉中膜厚度明显加重；肌化评分明显升高；炎症评分显著升高。与模型组比较，阿托伐他汀预防组上述指标均有改善，同时肺动脉平滑肌细胞增殖显著减少,细胞凋亡率显著增加，RhoA、ROCKII的表达显著下调。阿托伐他汀逆转组肺血管重构有改善趋势。..DHEA研究结果：与模型组比较，预防组DHEA治疗显著升高了血浆DHEA水平，降低了肺动脉平均圧，改善了肺血管重构与右心室肥厚，降低了右室舒张末内径，同时抑制了STAT3信号通路相关因子表达，而心脏彩超测左心室射血分数、左心室舒张末内径等指标无明显改变。逆转组DHEA治疗结果与预防组类似，但改善程度较低。..结论：.阿托伐他汀可能通过抑制RhoA/Rho激酶改善PH-LHF的肺血管重构。DHEA在不影响左心结构与功能情况下，通过抑制STAT3信号通路预防与逆转PH-LHF模型肺血管重构。