胸交感神经阻滞对低氧性肺动脉高压大鼠的影响

Effect of thoracic sympathetic blockade on hypoxic pulmonary arterial hypertension in rats

目的研究胸交感神经阻滞（TSB）对低氧性肺动脉高压（HPH）大鼠平均肺动脉压（mPAP）及病理形态学的影响。方法选择健康雄性Wistar大鼠48只，随机分为正常对照组、模型组、罗哌卡因组及生理盐水组，每组各12只。正常对照组在常氧常压下饲养3周，其余三组大鼠在自制常压低氧（10．0±0．5）％舱内饲养3周，同时罗哌卡因组和生理盐水组给与胸段硬膜外腔置管分别注入0．2％罗哌卡因和0．9％生理盐水各50止行胸段（胸1—5）交感神经阻滞术（TSB）。分别测定各组大鼠平均肺动脉压（mPAP）、右心室肥厚指数（RV／LV＋S）；观察HE染色的肺组织小动脉变化，利用图像分析技术测定大鼠肺小动脉管壁厚度指标[管壁厚度与血管外周径的百分比（WT％）和管壁面积与血管总面积的百分比（WA％）]。结果①模型组大鼠mPAP、RV／LV＋S、WA％和WT％明显高于正常对照组，肺组织切片HE染色显示，肺小动脉管壁明显增厚，管腔明显狭窄；②罗哌卡因组mPAP明显降低，Rv／LV＋S比值减小，肺小动脉管壁厚度降低。结论TSB能够降低HPH大鼠的mPAP，改善肺血管和右心室的重构。

Objective To investigate the effect of thoracic sympathetic blockade （TSB） on mean pulmonary arterial pressure （mPAP）, cardiac structure, structure of small pulmonary arteries on hypoxic pulmonary hypertension （HPH） in rats. Methods Forty -eight healthy male Wistar rats were randomly divided into normal control group （12 rats）, model group （12 rats）, ropivacaine group （12 rats） and normal sodium group （ 12 rats）. Normal control group were rearing in normal pressure and normoxia for 3 weeks. Other groups animals were placed in a hypoxia chamber （ 10.0± 0.5） % and instrumented with epidural catheters at the thoracic level. Rats were injected with saline or ropivacaine. Haemodynamic measurements included pulmonary artery pressure and index of right ventricular hypertrophy. Degree of pulmonary vascular remodeling was determined by HE staining. WA% and WT% were determined by image analysis technique. Results （1）The mPAP, RV/LV ＋ S, WA% and WT% in rats of model group were increasing strikingly after normal pressure and hypoxia for 3 weeks. （2）Compared with model group and normal sodium group, the mPAP, RV/LV ＋ S and pulmonary small artery wall thickness of the rats in ropivacaine group were decreasing strikingly. Conclusion TSB can reduce mPAP and improve pulmonary vascular and right ventricular remodeling.