中文摘要：

目的 探讨N-乙酰半胱氨酸对肺心病肺动脉压的影响及其机制。方法 将肺心病患者随机分为常规治疗组和常规治疗＋N-乙酰半胱氨酸治疗组（N-乙酰半胱氨酸组），测定两组治疗前、后的右室射血前期时间与肺动脉血流加速时间比值（RVPEP／AT）的变化，作为衡量肺动脉压的指标；此外，测定健康组及两治疗组治疗前、后的循环内皮细胞（CEC）计数、血浆内皮素-1（ET-1）和一氧化氮（NO）含量的变化。结果 治疗前两治疗组CEC计数和血浆ET-1明显高于健康组，而NO明显低于健康组（P均〈0．01）。两治疗组治疗后RVPEP／AT、CEC计数和ET-1含量均低于治疗前，而NO高于治疗前（P〈0．01或P〈0．05）；但所有这些变化均以N-乙酰半胱氨酸组的变化程度更明显（P〈0．01）。结论 N-乙酰半胱氨酸有助于肺心痛患者肺动脉高压的缓解，其机制可能与保护肺血管内皮细胞、重建血管活性因子平衡有关。

英文摘要：

Objective To investigate the effect of N - acetylcysteine （NAC） on pulmonary hypertension in patients with pulmonary heart disease （PHD） and its possible mechanism. Methods Patients with PHD were randomly assigned to receive slandard therapy （ standard therapy group） and standard therapy plus NAC group （NAC group）. The ratio of right ventricular pre -ejection period to the pulmonary flow acceleration time （RVPEP/AT） ,an indicator of puhnonary hypertension, were iueasured in PHD patients before and after treatment. In addition, circulating endothelial cell count （CEC） ,plasma endothelin - 1 （ ET - 1 ） and nitric oxide （NO） levels were tested in healthy control group and PHD patients before, and after treatment, respetively. Results Before treatment, CEC and plasma ET - 1 levels were significantly higher, while plasma NO levels were significantly lower in PHD patients as compared with healthy control group （ P 〈0.01 ）. After treatment, RVPEP/AT, CEC and plasma ET- 1 levels decreased and plasma NO levels increased significantly in the both therapy groups（ P 〈 0.01 orP 〈0.05）. But all these changes were greater in NAC group than in standard therapy group（ P 〈0.01 ）. Conclusion NAC is useful tor relieving pulmonary hypertension in PHD patients. Protection of pulmonary vascular endothelial cell and reconstruction of balance of wasoactive faetors may be the mechanism.