An x-ray diffraction study of corneal structure in mimecan-deficient mice
An x-ray diffraction study of corneal structure in mimecan-deficient mice
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DOI：
10.1167/iovs.05-0325
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发表时间：
2005-11-01
影响因子：
4.4
通讯作者：
Quantock, AJ
中科院分区：
文献类型：
--
作者：
Beecher, N;Carlson, C;Quantock, AJ
目的。角膜基质中的硫酸角蛋白多糖(KSPGs)被认为影响胶原纤维的排列。方法对9只野生型(n=9)和m imecan缺陷型(n=10)小鼠角膜进行了低角同步辐射x射线衍射法研究，以确定基质中胶原纤维的平均间距、平均胶原纤维直径和纤维组织水平。结果：在m imecan缺失小鼠的角膜中，平均胶原纤维直径为整个组织厚度的平均值，与正常(35.6+/-1.1 nm vs.35.9+/-1.0 nm)无明显差异。突变的角膜中胶原纤维的平均中心间距为52.6+/-2.6 nm，与野生型小鼠的53.3+/-4.0 nm相似。与野生型角膜(28.2+/-4.8)相比，MIMECAN缺失的角膜(23.4+/-5.6)的胶原纤维排列的局部有序程度，如背景减去的纤维间X射线反射的高度-宽度(H：W)所指示的，也没有明显的变化。结论：平均而言，在整个角膜基质深度，MIMECAN缺失的小鼠的胶原纤维与LUMICAN缺失的小鼠和角质形成缺失的小鼠的胶原纤维不同，具有正常的直径，正常的间隔和排列。这表明，与LUMICAN和KERATOCAN相比，MIMECAN在控制小鼠角膜基质构筑方面的作用较小。
PURPOSE. Keratan sulfate proteoglycans (KSPGs) in the corneal stroma are believed to influence collagen fibrillar arrangement. This study was performed to investigate the fibrillar architecture of the corneal stroma in mice homozygous for a null mutation in the corneal KSPG, mimecan.METHODS. Wild-type ( n = 9) and mimecan-deficient ( n = 10) mouse corneas were investigated by low-angle synchrotron x-ray diffraction to establish the average collagen fibrillar spacing, average collagen fibril diameter, and level of fibrillar organization in the stromal array.RESULTS. The mean collagen fibril diameter in the corneas of mimecan-null mice, as an average throughout the whole thickness of the tissue, was not appreciably different from normal (35.6 +/- 1.1 nm vs. 35.9 +/- 1.0 nm). Average center-to-center collagen fibrillar spacing in the mutant corneas measured 52.6 +/- 2.6 nm, similar to the 53.3 +/- 4.0 nm found in wild-type mice. The degree of local order in the collagen fibrillar array, as indicated by the height-width ( H: W) ratio of the background-subtracted interfibrillar x-ray reflection, was also not significantly changed in mimecan-null corneas (23.4 +/- 5.6), when compared with the corneas of wild-types (28.2 +/- 4.8).CONCLUSIONS. On average, throughout the whole depth of the corneal stroma, collagen fibrils in mimecan-null mice, unlike collagen fibrils in lumican-null mice and keratocan-null mice, are of a normal diameter and are normally spaced and arranged. This indicates that, compared with lumican and keratocan, mimecan has a lesser role in the control of stromal architecture in mouse cornea.