Xia Wei, de Bock Charles, Murrell George A C, Wang Yao
Orthopaedic Research Institute, The St. George Hospital, University of New South Wales, Kogarah, Sydney, NSW 2217, Australia .
J Orthop Res. 2003 Sep;21(5):819-25. doi: 10.1016/S0736-0266(03)00058-5.
The urokinase-type plasminogen activator (uPA) system has been implicated in cell migration, angiogenesis, extracellular matrix synthesis and tissue remodelling. However, little is known about the role of the system in tendon healing. We used a rat Achilles tendon model to study mRNA and protein expression of uPA and its receptor (uPAR) during tendon healing using immunohistochemical, Northern and Western blot analyses. Time-dependent increases in uPA/uPAR mRNAs and proteins, maximal on days 4-7 and 7-14 respectively, were found following Achilles tendon division. Interestingly, uninjured control tendons expressed uPA mRNA and protein, but little uPAR transcripts and protein. On day 14 following Achilles tendon division, uPA receptor protein increased 12.6-fold (p<0.001) while uPA itself increased only 1.3-fold (p<0.05). Immunohistochemical analyses revealed that both uPAR/uPA positive staining cells were increased in the healing tendon tissue section. These findings show for the first time that uPA, and especially its receptor uPAR, are up-regulated during tendon healing.
尿激酶型纤溶酶原激活剂（uPA）系统与细胞迁移、血管生成、细胞外基质合成及组织重塑有关。然而，该系统在肌腱愈合中的作用却鲜为人知。我们使用大鼠跟腱模型，通过免疫组织化学、Northern印迹和Western印迹分析，研究肌腱愈合过程中uPA及其受体（uPAR）的mRNA和蛋白表达。跟腱切断后，发现uPA/uPAR的mRNA和蛋白呈时间依赖性增加，分别在第4 - 7天和第7 - 14天达到最大值。有趣的是，未受伤的对照肌腱表达uPA的mRNA和蛋白，但uPAR的转录本和蛋白很少。跟腱切断后第14天，uPA受体蛋白增加了12.6倍（p<0.001），而uPA本身仅增加了1.3倍（p<0.05）。免疫组织化学分析显示，愈合肌腱组织切片中uPAR/uPA阳性染色细胞均增加。这些发现首次表明，在肌腱愈合过程中uPA，尤其是其受体uPAR上调。
