Jones B E, Thompson E W, Hodos W, Waldbillig R J, Chader G J
Laboratory of Retinal Cell and Molecular Biology, National Eye Institute, National Institute of Health, Bethesda, MD 20892, USA.
Exp Eye Res. 1996 Oct;63(4):369-81. doi: 10.1006/exer.1996.0127.
In the avian model of myopia, retinal image degradation quickly leads to ocular enlargement. We now give evidence that regionally specific changes in ocular size are correlated with both biomechanical indices of scleral remodeling, e.g. hydration capacity and with biochemical changes in proteinase activities. The latter include a 72 kDa matrix metalloproteinase (putatively MMP-2), other gelatin-binding MMPs, an acid pH MMP and a serine protease. Specifically, we have found that increases in scleral hydrational capacity parallel increases in collagen degrading activities. Gelatin zymography reveals that eyes with 7 days of retinal image degradation have elevated levels (1.4-fold) of gelatinolytic activities at 72 and 67 kDa M(r) in equatorial and posterior pole regions of the sclera while, after 14 days of treatment, increases are no longer apparent. Lower M(r) zymographic activities at 50, 46 and 37 kDa M(r) are collectively increased in eyes treated for both 7 and 14 days (1.4- and 2.4-fold respectively) in the equator and posterior pole areas of enlarging eyes. Western blot analyses of scleral extracts with an antibody to human MMP-2 reveals immunoreactive bands at 65, 30 and 25 kDa. Zymograms incubated under slightly acidic conditions reveal that, in enlarging eyes, MMP activities at 25 and 28 kDa M(r) are increased in scleral equator and posterior pole (1.6- and 4.5-fold respectively). A TIMP-like protein is also identified in sclera and cornea by Western blot analysis. Finally, retinal-image degradation also increases (approximately 2.6-fold) the activity of a 23.5 kDa serine proteinase in limbus, equator and posterior pole-sclera that is inhibited by aprotinin and soybean trypsin inhibitor. Taken together, these results indicate that eye growth induced by retinal-image degradation involves increases in the activities of multiple scleral proteinases that could modify the biomechanical properties of scleral structural components and contribute to tissue remodeling and growth.
在鸟类近视模型中，视网膜图像退化会迅速导致眼球增大。我们现在提供证据表明，眼球大小的区域特异性变化与巩膜重塑的生物力学指标（如水化能力）以及蛋白酶活性的生化变化相关。后者包括一种72 kDa的基质金属蛋白酶（推测为MMP - 2）、其他明胶结合MMPs、一种酸性pH值的MMP和一种丝氨酸蛋白酶。具体而言，我们发现巩膜水化能力的增加与胶原蛋白降解活性的增加平行。明胶酶谱分析显示，视网膜图像退化7天的眼睛，在巩膜赤道和后极区域，72 kDa和67 kDa M(r)的明胶水解活性水平升高（1.4倍），而在治疗14天后，这种增加不再明显。在眼球增大的赤道和后极区域，经7天和14天治疗的眼睛中，50 kDa、46 kDa和37 kDa M(r)的较低M(r)酶谱活性总体上有所增加（分别为1.4倍和2.4倍）。用抗人MMP - 2抗体对巩膜提取物进行蛋白质印迹分析，显示在65 kDa、30 kDa和25 kDa处有免疫反应条带。在略酸性条件下孵育的酶谱显示，在眼球增大的情况下，巩膜赤道和后极处25 kDa和28 kDa M(r)的MMP活性增加（分别为1.6倍和4.5倍）。通过蛋白质印迹分析在巩膜和角膜中也鉴定出一种TIMP样蛋白。最后，视网膜图像退化还使角膜缘、赤道和后极巩膜中一种23.5 kDa丝氨酸蛋白酶的活性增加（约2.6倍），该酶被抑肽酶和大豆胰蛋白酶抑制剂抑制。综上所述，这些结果表明，视网膜图像退化诱导的眼球生长涉及多种巩膜蛋白酶活性的增加，这些蛋白酶可能会改变巩膜结构成分的生物力学特性，并有助于组织重塑和生长。
