【作者】 韩李周；

【导师】 袁雅冬；

【作者基本信息】 河北医科大学 ， 内科学， 2008， 硕士

【摘要】 目的:右心功能不全是肺栓塞(pulmonary embolism,PE)重要的病理生理改变之一,与疾病的预后密切相关。超声心动图是评价心功能的常用工具,可以发现肺动脉高压、右室高负荷和肺源性心脏病的征象,是划分次大面积肺栓塞的依据。血清生物学指标能否早期识别PE心肌损伤是临床工作中关注的问题。氨基末端脑钠肽前体(N-terminal pro-brain natriuretic peptide,NT-proBNP)和心肌型脂肪酸结合蛋白(heart-type fatty acid binding protein,H-FABP)是最近提出的反应心功能障碍、心肌缺血的敏感指标。近来国外常有心肌损伤生化指标与PE危险性分层的临床研究,但是很少短期连续监测其血清变化、描述它们的释放特征。本实验通过建立急性肺栓塞(acute pulmonary embolism,APE)模型,检测二者的血清变化,为临床优化选择生化指标提供依据,并结合心肌组织光镜及电镜下结构变化,探讨PE心肌损伤的机制。方法:健康新西兰大耳白兔24只,雌雄不拘,体重2.5～3.5Kg。采用Berman球囊漂浮导管置入兔左下肺动脉开口处,充盈球囊,建立兔肺栓塞动物模型。随机分为4组:(1)假手术组(n=6),(2)栓塞0.5h组(n=6),(3)栓塞1h组(n=6),(4)栓塞2h组(n=6)。各组动物分别于栓塞前、栓塞即刻、栓塞0.5小时、栓塞1小时、栓塞2小时等时间点监测肺动脉收缩压(pulmonary arterial systolic pressure,PASP)、肺动脉舒张压(pulmonary arterial diastolic pressure,PADP)、肺动脉平均压(pulmonary arterial mean pressure,PAMP)。于栓塞前、栓塞0.5小时、栓塞1小时、栓塞2小时等时间点抽取静脉血,离心,取上清夜,采用双抗体夹心ELISA法,测定血清NT-proBNP、H-FABP含量。各动物分别于相应时间处死,取左、右室心肌组织,4%多聚甲醛、4%戊二醛固定,制作心肌H-E切片、电镜标本,观察心肌组织病理及超微结构变化。结果:(1)各组动物实验中肺动脉压的变化:除假手术组外,各组实验动物PADP、PAMP、PASP在栓塞即刻急剧升高,明显高于栓塞前水平(P均<0.05),栓塞0.5h开始下降,1h继续下降,但仍明显高于栓塞前水平(P<0.05),栓塞2h下降至栓塞前水平。(2)各组血清中NT-proBNP浓度的变化:除假手术组外,栓塞0.5h组、栓塞1h组、栓塞2h组各时间点血清NT-proBNP浓度均高于栓塞前水平(P均<0.05),栓塞0.5h即升高,栓塞1h、2h继续升高;组间各对应时间点比较,栓塞1h、2h血清NT-proBNP浓度变化有统计学意义(P<0.05)。(3)各组血清中H-FABP浓度变化:栓塞0.5h、栓塞1h、栓塞2h各时间点血清H-FABP浓度均高于栓塞前及假手术组(P均<0.05),栓塞0.5h即显著升高,栓塞1h、2h继续升高。(4)光镜下H-E染色显示,假手术组心肌细胞排列整齐,核呈椭圆形,位于中央,染色淡。栓塞组心肌细胞排列紊乱,核固缩,染色深,可见组织水肿。对照组与实验组均未见心肌出血、灶性坏死等改变。透射电镜显示,假手术组心肌细胞内可见大量线粒体,结构清晰,嵴排列整齐。栓塞组心肌细胞内线粒体明显肿胀,嵴排列紊乱,部分线粒体嵴崩解,空泡变,甚至破裂。部分肌小节断裂。结论:(1)心肌组织病理及电镜超微结构变化,提示在急性肺栓塞发生后存在心肌损伤。(2)肺血管阻力、肺循环压力和心输出量相互影响,共同形成PE心血管病理生理变化的基础。(3)NT-proBNP、H-FABP可以作为PE心肌损伤的生物学指标,联合监测其变化对指导治疗及判断预后等都具有一定意义。更多还原

【Abstract】 Objective: Right ventricular dysfunction is one of the most important physiopathologic change following pulmonary embolism (PE) and a strong predictor of poor clinical outcome. Echocardiogram is a useful instrument to evaluate heart function, which could show the signs of pulmoanry hypertension, right ventricular overload and pneumocardial disease. According to the sighs aforementioned, sub-massive pulmonary embolism is subdivided. It is still uncertain that the biomarkers detect myocardial injury earlier. N-terminal pro-brain natriuretic peptide (NT-proBNP) and heart-type fatty acid binding protein (H-FABP) are sensitive biomarkers for heart failure and myocardial ischemic injury, which are advocated recently. There are several foreign clinical studies on biomarkers and risk stratification of PE but few of them monitor the serumal concentrations consecutively. In this model of PE, we detect the content of NT-proBNP and H-FABP in serum consecutively, to describe the release kinetics of them, which may be useful for optimization of biomarkers.Meanwhile, revealing the mechanisms of myocardial injury rely on histopathologic and ultramicrostructure changes of myocardium. Method: twenty-four New Zealand rabbits of either gender and weighing 2.5~3.5kg were studied, which the left lower lung artery were obstructed by inflating gas of 5F Berman sacculus catheter to set up rabbit pulmonary embolism model. The animals were randomly divided into four groups: (1)sham operation group(n=6), (2)embolism 0.5h group (n=6), (3)embolism 1h group (n=6), (4)embolism 2h group (n=6). Pulmonary arterial systolic pressure(PASP), pulmonary arterial diastolic pressure(PADP), and pulmonary arterial mean pressure(PAMP) were monitored, and the pulmonary pressure at pre-embolization, embolization instantly, embolization 0.5h, 1h, 2h were recorded. Drawing venous blood of all group rabbits at the corresponding time, centrifuged, then extracted the supernatant. All the serum were preserved in the -20℃refrigerator before the contents of NT-proBNP、H-FABP were measured by sandwich enzyme-linked immunosorbent assay. The rabbits were killed at the end of experiments, and the ventricular myocardium tissue specimen was fixed by 4% polyformaldehyde and 4% glutaraldehyde respectively, then histopathologic and ultramicrostructure changes of myocardium were studied by light microscope and electron micrograph.Results: (1)The change of pulmonary pressure: except for the sham operation group, PASP, PADP, and PAMP were rapidly increased at the moment of embolization, and were higher significantly than pre-embolization(P<0.05,respectively). PASP, PADP, and PAMP were decreased gradually at embolization 0.5h, 1h, but still higher significantly than pre-embolization(P<0.05,respectively), and then decreased to the level of pre-embolization. (2)The change of serum NT-proBNP: except for the sham operation group, the content of NT-proBNP were higher significantly at embolization 0.5h, 1h, and 2h than pre-embolization(P<0.05,respectively), and gradually increased accompanied the prolongation of embolization. When contrasting to the value of corresponding time in different groups, only the content of embolization 1h and 2h were higher significantly than the sham operation group (P <0.05,respectively). (3)The change of serum H-FABP: The content of serum H-FABP were higher significantly at embolization 0.5h, 1h, and 2h than pre-embolization and the sham operation group(P<0.05,respectively). At embolization 2h, there was still not sign of decrease. (4)Histopathologic change of ventricular myocardium: in both sham group and embolism groups, there were not signs of myocardium focal necrosis and bleeding with hematoxylin-eosin staining (H-E staining) under light microscope examination. But in embolism group, myocardial cell nucleus stained darker, even karyopycnosis,and myocardium edema was seen. Transmission electron microscope showed mitochondria swelling, cristae structure derangement, partial cristae disaggregation, vacuolization, even the whole mitochondrion rupture,partial sarcomere disruption in the experimental group.Conclusion: (1)Histopathologic and ultramicrostructure changes of myocardium show the myocardial ischemic injury in PE. (2)Pulmonary vascular resistance, pulmonary arterial pressure and cardiac output interact, to form the base of physiopathologic change of cardiovascular system in PE.(3)NT-proBNP、H-FABP may be the earlier biomarker of myocardial injury, monitoring the contents in serum together is helpful for risk stratification and therapy in PE.更多还原