Yasui Takeshi, Tohno Yoshiyuki, Araki Tsutomu
Osaka University, Graduate School of Engineering Science, Toyonaka, Osaka, 560-8531 Japan.
J Biomed Opt. 2004 Mar-Apr;9(2):259-64. doi: 10.1117/1.1644116.
We have proposed an optical probe that can be used to characterize the orientation of collagen fibers in human dermis. A specific probing ability for collagen results from the use of second-harmonic-generation (SHG) light induced by collagen molecules in the tissue. Based on the concept of collagen SHG light, a reflection-type polarization measurement system (named SHG polarimetry) with a probe light spot of 15 microm in diameter has been constructed, and the human reticular dermis has been measured using this system. Resultant data exhibit that the reticular dermis possesses approximately uniaxial orientation of the collagen fibers. Furthermore, we demonstrated a nondestructive measurement of the collagen orientation in the papillary dermis across an epidermis layer. For distribution measurement of the collagen fiber orientation in the reticular dermis, we have extended the SHG polarimetry to one- (1-D) and two-dimensional (2-D) measurement. By the macroscopic 2-D SHG polarimetry, we have observed that the orientation angle and organization degree of collagen fibers vary widely depending on the discrete probing positions in the reticular dermis. Furthermore, microscopic 1-D SHG polarimetry indicated a swell of the orientation angle and a large variance of the organization degree in the collagen fibers in the microscopic region. These results imply that the reticular dermis posses a tangled structure of collagen fibers, which is highly consistent with the result of the anatomical examination of the skin. The proposed method will be a powerful tool for monitoring the microscopic distribution of the collagen fiber orientation in the human dermis.
我们提出了一种可用于表征人真皮中胶原纤维取向的光学探针。对胶原的特定探测能力源于利用组织中胶原分子诱导产生的二次谐波（SHG）光。基于胶原SHG光的概念，构建了一种探针光斑直径为15微米的反射型偏振测量系统（称为SHG偏振测量法），并使用该系统对人网状真皮进行了测量。所得数据表明，网状真皮中的胶原纤维具有近似单轴取向。此外，我们展示了一种跨越表皮层对乳头真皮中胶原取向进行无损测量的方法。为了测量网状真皮中胶原纤维取向的分布，我们将SHG偏振测量法扩展到了一维（1-D）和二维（2-D）测量。通过宏观二维SHG偏振测量法，我们观察到胶原纤维的取向角和组织程度因在网状真皮中的离散探测位置而有很大差异。此外，微观一维SHG偏振测量法表明，在微观区域的胶原纤维中，取向角有增大现象，且组织程度存在很大差异。这些结果意味着网状真皮具有胶原纤维的缠结结构，这与皮肤解剖检查的结果高度一致。所提出的方法将成为监测人真皮中胶原纤维取向微观分布的有力工具。
