高肺血流量对肺血管结构及内源性硫化氢影响

The effects of high pulmonary blood flow on pulmonary vascular structure and endogenous hydrogen sulflde

目的 探讨高肺血流量所致肺动脉高压(PH)大鼠肺血管结构和血浆硫化氢的变化。方法 雄性SD大鼠共16只。对分流组大鼠行腹主动脉、下腔静脉分流术;11周后以右心导管法测定肺动脉平均压(mPAP);检测右心室/体重(RV/BW)和右心室/左心室+室间隔(RV/LV+S)比值;并以光学显微镜和电子显微镜观测肺血管结构变化;以分光光度法测定血浆硫化氢含量。结果 分流组大鼠mPAP、RV/BW及RV/(LV+S)比值均明显高于对照组(P均<0.01);光镜下肺小血管肌化程度明显增强,肺中、小肌型动脉相对中膜厚度明显增加;电镜下,肺中、小肌型动脉内皮细胞增生、肥厚、肿胀,平滑肌细胞增生、肥厚,并由收缩表型向合成表型转化。分流组大鼠的血浆H_2S含量明显低于对照组,肺动脉平均压与血浆硫化氢含量呈负相关。结论 肺血管结构重建是高肺血流量所致PH重要病理基础,内源性H_2S下调可能在其形成中起重要作用。

Objective To explore the alterations of pathologic structure and endogenous hydrogen sulfide in rats with pulmonary hypertension induced by high pulmonary blood flow. Methods There were 16 SD rats used in this study. Abdominal aorta and vena ca-va inferior shunting was conducted in shunting group. Mean pulmonary artery pressure(mPAP) was monitored by right ventricular (RV) duct after 11 weeks. The value of RV / body weight (BW) and RV/LV + interventricular septum was also monitored. The alterations of pulmonary vascular micro- and ultra- structure were also examined by electronic microscope. Meanwhile the concentration of plasma hydrogen sulfide (US) was measured by spectrophoteries. Results After 11 weeks of aortocaval shunting,mPAP. significantly increased. Muscularization of small pulmonary vessels and relative medial thickness of pulmonary arteries were obviously raised in shunting rats compared with controls. Ultrastructure of intrapulmonary arteries changed obviously in shunting rats. Meanwhile, plasma US concentration decreased and a negative correlation existed between mPAP and plasma US concentration. Conclusions Pulmonary vascular structural remodeling may be the important pathologic basis of pulmonary hypertension induced by high pulmonary blood flow. Endogenous H2S might play an important role in the development of high pulmonary blood flow-induced pulmonary hypertension.