N-乙酰半胱氨酸对COPD肺动脉高压大鼠肺组织PI3K-Akt-eNOS-NO信号通路的影响

Effect of N-acetylcysteine on PI3K-Akt-eNOS-NO signaling pathway in pulmonary tissues of rats with COPD pulmonary hypertension

【目的】探讨N-乙酰半胱氨酸对慢性阻塞性肺疾病(chronic obstructive pulmonary disease,COPD)肺动脉高压大鼠肺组织PI3K-Akt-eNOS-NO信号通路的影响。【方法】以烟熏、低氧、气道内滴注脂多糖法制备COPD肺动脉高压大鼠模型,随机分为模型组、N-乙酰半胱氨酸低剂量(50 mg/kg)组、N-乙酰半胱氨酸中剂量(100 mg/kg)组、N-乙酰半胱氨酸高剂量(200 mg/kg)组、波生坦(100 mg/kg)组,每组12只,另取12只设为对照组,检测各组大鼠肺平均动脉压;HE染色检测各组大鼠肺组织病理形态变化;酶联免疫吸附实验试剂盒检测各组大鼠血清中肿瘤坏死因子α(tumor necrosis factor,TNF-α)、白细胞介素-6(interleukin-6,IL-6)、内皮型一氧化氮合酶(endothelial nitric oxide synthase,eNOS)、NO水平;蛋白免疫印迹法检测各组大鼠肺组织PI3K/Akt/eNOS通路相关蛋白表达。【结果】与对照组比较,模型组大鼠肺小动脉呈现管壁增生且明显增厚,管腔变窄甚至闭塞等病理损伤,肺平均动脉压、大鼠血清中TNF-α及IL-6水平升高(P<0.05),大鼠血清中eNOS及NO水平、大鼠肺组织磷酸化磷脂酰肌醇-3-激酶(phosphorylated phosphatidylinositol 3-kinases,p-PI3K)/磷脂酰肌醇-3-激酶(phosphatidylinositol 3-kinases,PI3K)、磷酸化蛋白激酶B(phosphorylated protein kinase B,p-AKT)/蛋白激酶B(protein kinase B,PKB/Akt)及p-eNOS/eNOS降低(P<0.05);与模型组比较,N-乙酰半胱氨酸低、中、高剂量组及波生坦组大鼠肺小动脉病理损伤减轻,肺平均动脉压、大鼠血清中TNF-α及IL-6水平降低(P<0.05),大鼠血清中eNOS及NO水平、大鼠肺组织p-PI3K/PI3K、p-AKT/Akt及peNOS/eNOS升高且N-乙酰半胱氨酸各组呈剂量依赖性(P<0.05);N-乙酰半胱氨酸高剂量组与波生坦组相比,差异无统计学意义(P>0.05)。【结论】N-乙酰半胱氨酸可改善COPD肺动脉高压大鼠临床症状,可能是通过激活PI3K-Akt-eNOS-NO通路实现的。

【Objective】To explore the effect of N-acetylcysteine on PI3K-Akt-eNOS-NO signaling pathway in pulmonary tissues of rats with chronic obstructive pulmonary disease(COPD)and pulmonary hypertension.【Methods】The rat models with COPD and pulmonary hypertension were established by smoking,hypoxia and intratracheal instillation of lipopolysaccharide,then randomly divided into model group,low dose N-acetylcysteine(50 mg/kg),medium dose N-acetylcysteine(100 mg/kg),high dose N-acetylcysteine(200 mg/kg)and bosentan(100 mg/kg)groups,12 rats per group.Another 12 rats were set as control group.The mean pulmonary arterial pressure was measured.HE staining was used to detect the pathological changes of lung tissues.The levels of serum TNF-α,IL-6,endothelial nitric oxide synthase(eNOS)and NO were detected by ELISA and the expression of PI3K/Akt/eNOS pathway related proteins was detected by Western blotting.【Results】Compared with the control group,the pulmonary arterioles in the model group showed hyperplasia and obvious thickening of the wall,narrowing and even occlusion of the lumen.The mean pulmonary arterial pressure and levels of TNF-αand IL-6 in serum were increased(P<0.05),and the levels of eNOS and NO in serum,p-PI3K/PI3K,p-Akt/Akt and p-eNOS/eNOS in lung tissues were decreased(P<0.05).Compared with the model group,the pathological damage of pulmonary arterioles in the low,middle and high dose N-acetylcysteine groups and bosentan group was reduced,the mean pulmonary arterial pressure and levels of TNF-αand IL-6 in serum were decreased(P<0.05),and the levels of eNOS and NO in serum,p-PI3K/PI3K,p-Akt/Akt and p-eNOS/eNOS in lung tissues of rats were increased,and there was a dose-dependent manner in N-acetylcysteine groups(P<0.05).However,there was no significant difference between high dose N-acetylcysteine group and bosentan group(P>0.05).【Conclusion】N-acetylcysteine can improve the clinical symptoms of COPD rats,which may be related to activating PI3K-Akt-eNOS-NO pathway.