Analysis of collagen fiber orientation in biological tissues using polarization-resolved second-harmonic-generation microscopy

摘要

Collagen plays an important role as a structural protein to determine the morphology and the mechanical property of tissues. Collagen orientation is one important parameter closely related with the mechanical property because collagen possesses fiber structure in tissues. However, it is difficult to evaluate the collagen fiber orientation quantitatively without invasiveness. In this article, we constructed continuously-polarization-resolved second-harmonic-generation (SHG) microscopy based on rapid polarization rotation every 15 degrees with electric-optic modulator, and applied it for the quantitative analysis of collagen fiber orientation. The orientation angle and degree of collagen fiber in different biological tissues were extracted from the curve fitting with a model function to a series of polarization-resolved SHG images. The extracted parameters clearly indicate difference of collagen fiber orientation between different tissues.