Hsueh Chiu-Mei, Lo Wen, Chen Wei-Liang, Hovhannisyan Vladimir A, Liu Guang-Yu, Wang Sheng-Shun, Tan Hsin-Yuan, Dong Chen-Yuan
Department of Physics, National Taiwan University, Taipei, Taiwan.
Biophys J. 2009 Aug 19;97(4):1198-205. doi: 10.1016/j.bpj.2009.05.040.
The purpose of this study was to image and quantify the structural changes of corneal edema by second harmonic generation (SHG) microscopy. Bovine cornea was used as an experimental model to characterize structural alterations in edematous corneas. Forward SHG and backward SHG signals were simultaneously collected from normal and edematous bovine corneas to reveal the morphological differences between them. In edematous cornea, both an uneven expansion in the lamellar interspacing and an increased lamellar thickness in the posterior stroma (depth > 200 microm) were identified, whereas the anterior stroma, composed of interwoven collagen architecture, remained unaffected. Our findings of heterogeneous structural alteration at the microscopic scale in edematous corneas suggest that the strength of collagen cross-linking is heterogeneous in the corneal stroma. In addition, we found that qualitative backward SHG collagen fiber imaging and depth-dependent signal decay can be used to detect and diagnose corneal edema. Our work demonstrates that SHG imaging can provide morphological information for the investigation of corneal edema biophysics, and may be applied in the evaluation of advancing corneal edema in vivo.
本研究的目的是通过二次谐波产生（SHG）显微镜对角膜水肿的结构变化进行成像和定量分析。牛角膜被用作实验模型来表征水肿角膜的结构改变。同时从正常和水肿牛角膜收集正向SHG和反向SHG信号，以揭示它们之间的形态差异。在水肿角膜中，发现板层间距不均匀扩大且后基质（深度>200微米）的板层厚度增加，而由交织胶原结构组成的前基质未受影响。我们在水肿角膜微观尺度上发现的异质性结构改变表明，角膜基质中胶原交联强度是异质的。此外，我们发现定性的反向SHG胶原纤维成像和深度依赖性信号衰减可用于检测和诊断角膜水肿。我们的工作表明，SHG成像可为角膜水肿生物物理学研究提供形态学信息，并可能应用于体内进展性角膜水肿的评估。
