急性肺栓塞后osteoglycin的表达及对胶原代谢的影响

Down-regulation of osteoglycin expression and its influence on the metabolism of collagen in the lung tissues after acute pulmonary embolism

目的研究大鼠急性肺栓塞模型肺组织中osteoglycin(OGN)的表达变化及其对胶原代谢的影响。方法建立大鼠急性肺栓塞模型,分别在急性肺栓塞后1、8、24和48h开胸取出肺组织,提取总RNA和总蛋白。以正常大鼠为对照组,采用半定量RT-PCR研究OGNmRNA的表达变化,采用Westernblot进一步验证OGN蛋白表达的变化,采用免疫组织化学方法检测肺栓塞前后大鼠肺组织中OGN的表达变化及组织分布情况,采用Masson染色观察急性肺栓塞4周后肺组织内的胶原沉积状况。结果在大鼠急性肺栓塞后,OGN在mRNA及蛋白水平均逐渐降低。免疫组化染色显示OGN主要分布在支气管黏膜上皮细胞下层、软骨组织和肺泡周围,且在肺动脉内皮细胞下层、外膜和肺静脉的内膜、中膜以及外膜均有分布。急性肺栓塞后OGN在上述组织内的表达均明显降低。急性肺栓塞4周后肺组织内的胶原沉积明显增加。结论大鼠急性肺栓塞后肺组织内OGN表达降低,促进了胶原在肺部的沉积。

Objective To study the changes in expression of osteoglycin （OGN） in the lung tissue in a rat acute pulmonary embolism （PE） model and its effects on the metabolism of collagen. Methods A rat acute PE model was reproduced by injecting 3-4 emboli into the left jugular vein. The lung tissue samples were collected at different time points as following： 1h, 8h, 24h and 48h, then the total RNA and total proteins of the lung tissue were extracted. Normal rats were used as control. The changes in mRNA level in OGN were assayed by semi-quantitative RT-PCR, and the changes in protein level were determined by Western blot method. The immunohistochemieal method was employed to study the distribution and expression changes in OGN in the lung tissue after PE. Masson staining was employed to observe the deposition of collagen in the lung tissue 4 weeks after acute PE. Results t different time points, the mRNA levels and the protein levels of OGN were lowered gradually in the lung tissue in rat acute PE models. The immunohistochemical study indicated that OGN was distributed beneath the bronchial epithelium, and in the periphery of cartilaginous tissue and the lung alveoli. It also could be observed beneath the arterial endothelium and in the adventitia of pulmonary arteries. In pulmonary veins, OGN accumulated in the adventitia, media, and intima. The deposition of collagen in the lung tissue increased obviously 4 weeks after acute PE. Conclusion The expression of OGN is down-regulated after acute PE. It facilitates the deposition of collagen in the lung tissue.