Changes of Biological Function of Vitreous body in Relation to the Onset of Diabetic Retinopathy.

目的：临床研究表明，糖尿病视网膜病变的发生和发展受到血管生成因子与其在玻璃体上/中的定位之间的关系的影响。作为视网膜病变模型建立的第一步，我们测定了TGF-β2和尿激酶型纤溶酶原激活物（u-PA）在鸡胚玻璃体中的定位。方法：将鸡玻璃体以105，000 g超浓缩1小时，观察等离子体处理后玻璃体生物学功能的变化。检测玻璃体匀浆、上清液（sup）和沉淀（ppt）中TGF-β2和u-PA的含量。用12.5%SDS-聚丙烯酰胺凝胶电泳法测定U-PA活性。结果：玻璃体经超离心分离后，ppt组分中活性TGF-β2的含量是sup组分的5倍以上。而且，几乎所有的u-PA都在ppt牵引中检测到。ppt组分中的U-PA分子量为55 kDa，似乎是二聚体。与未处理的玻璃体相比，等离子体处理的玻璃体上的细胞粘附活性增加。血浆处理后，血浆衍生的纤维连接蛋白和纤溶酶原在处理后的玻璃体中被检测到。结论：这些结果表明这些因子与玻璃体细胞外基质之间的相互作用对于了解玻璃体的生理作用，从而有效地预防眼内血管生成性疾病的重要性。

Purpose: Clinical trials have demonstrated that the onset and progression of diabetic retinopathy supposed to be influenced by the relation between angiogenic factors and their localization on /in the vitreous body. As the initial step of establishment for retinopathy model, we determine the localization of TGF-β2 and urokinase type plasminogen activator (u-PA) in the vitreous body of chick embryos. Moreover, we investigated the changes of biological function of vitreous body after plasma treatment.Methods: Chick vitreous bodies were ultracentrifuged for 1 hr at 105,000g. We measured TGF-β2 and u-PA in vitreous homogenate, supernatant (sup) and resuspended precipitate (ppt). U-PA activity was determined by zymography using 12.5% SDS-polyacrylamide gel. Cell adherent activity was compared with plasma-treated vitreous body and corresponding control.Results: After separation of the vitreous bodies by ultracentrifugation, ppt fraction contained more than 5 times the amount of active TGF-β2, compared to the sup fraction. Moreover, almost all of u-PA was detected in ppt traction. U-PA in ppt fraction has molecular weight of 55 kDa and seems to be dimmer. Cell adherent activity was increased on plasma-treated vitreous compared to non-treated one. After the treatment of plasma, plasma-derived fibronectin and plasminogen were detected in the treated-vitreous body.Conclusion: These results suggest the importance of the interaction between these factors and the vitreous extracellular matrix in order to understand the physiological role of vitreous body and thus to prevent intraocular angiogenic diseases effectively.