A Comparative Study of Vertebrate Corneal Structure: The Evolution of a Refractive Lens.
A Comparative Study of Vertebrate Corneal Structure: The Evolution of a Refractive Lens.
复制标题
脊椎动物角膜结构的比较研究：折射镜片的演变。
DOI：
10.1167/iovs.15-16584
复制
发表时间：
2015
影响因子：
4.4
通讯作者：
Jester,JamesV
中科院分区：
文献类型：
--
作者：
Winkler,Moritz;Shoa,Golroxan;Tran,StephanieT;Xie,Yilu;Thomasy,Sarah;Raghunathan,VijayK;Murphy,Christopher;Brown,DonaldJ;Jester,JamesV
目的：虽然角膜曲率在决定脊椎动物眼睛的屈光力方面起着重要作用，但控制角膜形状的机制在很大程度上仍然未知。为了解决这个问题，我们进行了脊椎动物角膜结构的比较研究，以确定与角膜屈光透镜的发展相关的潜在的基于进化的变化。使用二次谐波产生（SHG）信号的非线性光学（NLO）成像对来自不同脊椎动物分支的角膜中的胶原蛋白进行成像并三维重建板层组织。二次谐波产生的图像采取正常的角膜表面显示，角膜胶原蛋白在所有非哺乳类脊椎动物组织成片（鱼类和两栖动物）或带状（爬行动物和鸟类）从利姆布斯延伸到利姆布斯，定向几乎正交（范围从77.7-88.2）到他们的邻居。轻微的角度偏移（2-13）产生了一种旋转模式，这种模式在鱼类和两栖动物的整个厚度中持续存在，在爬行动物和鸟类中一直持续到最后一层。板层之间的相互作用仅限于软骨鱼类的“缝合”纤维，鱼类和两栖动物偶尔出现板层分支。在高等脊椎动物中，板层分支明显增加，因此鸟类>爬行动物>两栖动物>鱼类。相比之下，哺乳动物角膜显示出几乎随机的胶原纤维组织，没有正交的手性模式。我们的数据表明，非哺乳动物脊椎动物角膜共享一个共同的正交胶原蛋白结构组织，显示在更高的脊椎动物物种增加层状分支。重要的是，哺乳动物角膜显示出不同的结构组织，表明不同的进化背景。
Purpose.: Although corneal curvature plays an important role in determining the refractive power of the vertebrate eye, the mechanisms controlling corneal shape remain largely unknown. To address this question, we performed a comparative study of vertebrate corneal structure to identify potential evolutionarily based changes that correlate with the development of a corneal refractive lens.Methods.: Nonlinear optical (NLO) imaging of second-harmonic–generated (SHG) signals was used to image collagen and three-dimensionally reconstruct the lamellar organization in corneas from different vertebrate clades.Results.: Second-harmonic–generated images taken normal to the corneal surface showed that corneal collagen in all nonmammalian vertebrates was organized into sheets (fish and amphibians) or ribbons (reptiles and birds) extending from limbus to limbus that were oriented nearly orthogonal (ranging from 77.7–88.2) to their neighbors. The slight angular offset (2–13) created a rotational pattern that continued throughout the full thickness in fish and amphibians and to the very posterior layers in reptiles and birds. Interactions between lamellae were limited to “sutural” fibers in cartilaginous fish, and occasional lamellar branching in fish and amphibians. There was a marked increase in lamellar branching in higher vertebrates, such that birds≫ reptiles> amphibians> fish. By contrast, mammalian corneas showed a nearly random collagen fiber organization with no orthogonal, chiral pattern.Conclusions.: Our data indicate that nonmammalian vertebrate corneas share a common orthogonal collagen structural organization that shows increased lamellar branching in higher vertebrate species. Importantly, mammalian corneas showed a different structural organization, suggesting a divergent evolutionary background.