PDF(Pubmed)
Abstract：
The goal of this study was to evaluate the intensity of autophagy and ubiquitin-dependent proteolysis processes occurring in myocardium of left ventricle (LV) in subsequent stages of pulmonary arterial hypertension (PAH) to determine mechanisms responsible for LV mass loss in a monocrotaline-induced PAH rat model. LV myocardium samples collected from 32 Wistar rats were analyzed in an early PAH group (n = 8), controls time-paired (n = 8), an end-stage PAH group (n = 8), and their controls (n = 8). Samples were subjected to histological analyses with immunofluorescence staining, autophagy assessment by western blotting, and evaluation of ubiquitin-dependent proteolysis in the LV by immunoprecipitation of ubiquitinated proteins. Echocardiographic, hemodynamic, and heart morphometric parameters were assessed regularly throughout the experiment. Considerable morphological and hemodynamic remodeling of the LV was observed over the course of PAH. The end-stage PAH was associated with significantly impaired LV systolic function and a decrease in LV mass. The LC3B-II expression in the LV was significantly higher in the end-stage PAH group compared to the early PAH group (p = 0.040). The measured LC3B-II/LC3B-I ratios in the end-stage PAH group were significantly elevated compared to the controls (p = 0.039). Immunofluorescence staining showed a significant increase in the abundance of LC3 puncta in the end-stage PAH group compared to the matched controls. There were no statistically significant differences in the levels of expression of all ubiquitinated proteins when comparing both PAH groups and matched controls. Autophagy may be considered as the mechanism behind the LV mass loss at the end stage of PAH.
摘要：
这项研究的目的是评估在肺动脉高压（PAH）的后续阶段中左心室（LV）心肌中发生的自噬和泛素依赖性蛋白水解过程的强度，以确定在野百合碱诱导的PAH大鼠模型中导致LV质量损失的机制。在早期PAH组（n=8）中分析了从32只Wistar大鼠收集的LV心肌样本，控制时间配对(n=8)，终末期PAH组（n=8），和他们的控制（n=8）。用免疫荧光染色对样品进行组织学分析，通过蛋白质印迹法评估自噬，并通过泛素化蛋白的免疫沉淀评估LV中泛素依赖性蛋白水解。超声心动图,血液动力学,在整个实验过程中定期评估心脏形态参数。在PAH过程中，观察到LV的形态和血液动力学重塑。终末期PAH与LV收缩功能显着受损和LV质量减少有关。与早期PAH组相比，晚期PAH组LV中的LC3B-II表达明显更高（p=0.040）。与对照组相比，晚期PAH组中测量的LC3B-II/LC3B-I比率显着升高（p=0.039）。免疫荧光染色显示，与匹配的对照组相比，终末期PAH组中LC3斑点的丰度显着增加。当比较PAH组和匹配的对照时，所有泛素化蛋白的表达水平没有统计学上的显着差异。自噬可能被认为是PAH末期LV质量损失的机制。
