Objective To investigate expression changes and role of Gα11 protein in the processes of muscularization of non-muscular pulmonary arterioles and effect of sildenafil intervention in rats with pulmonary arterial hypertension (PAH).Methods Thirty SD rats were randomly divided into three groups,including normal control group,monocrotaline (MCT) group and sildenafil group;PAH model was prepared with 50 mg/kg MCT treatment for 4 weeks in the MCT group,and these rats were treated by 25 mg/kg sildenafil for 2 weeks after PAH formation in the sildenafil group,and the normal control group were treated with the equal amounts of physiological saline instead of monocrotaline;pulmonary artery pressure was measured with jugular vein catheterization;hematoxylin and eosin (HE) staining method was used to detect the pulmonary arteriolar morphology and vascular tissue parameters;expression of the target Gα11 protein,vascular smooth muscle marker osteopontin (OPN) and proliferation marker proliferating cell nuclear antigen (PCNA) was detected by Western blot.Results Pulmonary artery mean pressure (mPAP),non-muscular pulmonary arterioles wall thickness index (TI) and area index (AI) of the MCT group were higher than those of the normal control group [(27.43 ± 3.97) vs (11.93 ± 1.52) mmHg (1 mmHg =0.133 kPa),0.49±0.07 vs 0.31 ±0.09 and 0.74±0.05 vs 0.45 ±0.10] (all P＜0.05),and meanwhile the expression levels of Gα1 1 and the related proteins including OPN and PCNA were significantly enhanced.mPAP,TI and AI[(18.59 ± 1.44) mmHg,0.39 ±0.09 and 0.56 ±0.04] of the sildenafil group were all lower than those of the MCT group (all P＜0.05),and furthermore,expressions of Gα1 1,OPN and PCNA also reduced in line with these changes.Conclusion Gα1 1 protein plays a role in the development of PAH and pulmonary non-muscular arteriole muscularization,and sildenafil effectively suppresses PAH and pulmonary vascular remodeling by inhibiting Gα11 expression.%目的 探讨GTP结合蛋白α亚基11(Gα11)在肺动脉高压大鼠无肌动脉肌化过程中的表达及西地那非的干预作用.方法 将30只清洁级SD大鼠按随机数字表法随机均分为正常对照组、野百合碱组和西地那非组3组;后两组以50 mg/kg野百合碱腹腔注射4周制备肺动脉高压模型,且西地那非组在肺动脉高压形成后给予西地那非(25 mg/kg)灌胃2周,正常对照组以等量生理盐水替代野百合碱腹腔注射4周.颈静脉插管测量各组大鼠肺动脉压力,检测肺无肌动脉组织的形态学特征和血管增生程度,Western印迹法测定大鼠肺组织目标蛋白Gα11、血管平滑肌特征标志骨桥蛋白(OPN)和增殖细胞核抗原(PCNA)的表达情况并进行统计学分析.结果 野百合碱组的肺动脉平均压(mPAP)、肺无肌动脉管壁厚度指数(TI)和面积指数(AI)均显著高于正常对照组[(27.43±3.97)比(11.93±1.52) mmHg(1 mmHg=0.133 kPa)、0.49±0.07比0.31 ±0.09和0.74 ±0.05比0.45 ±0.10](均P＜0.05),同时Gc11及相关标记蛋白OPN和PCNA的表达量均明显增强;西地那非组mPAP、TI和AI[(18.59±1.44) mmHg、0.39±0.09和0.56±0.04]均显著低于野百合碱组(均P＜0.05),且Gα11、OPN和PCNA的表达也随之减弱.结论 Gα11蛋白与大鼠肺动脉高压肺无肌动脉肌化发生密切相关,西地那非通过抑制Go11表达可有效减轻肺动脉高压和肺血管重构.
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