Skin Collagen Fiber Molecular Order: A Pattern of Distributional Fiber Orientation as Assessed by Optical Anisotropy and Image Analysis

Autor(es)

Ribeiro, Juliana Fulan ^[1] ; Martins dos Anjos, Eli Heber ^[1] ; Mello, Maria Luiza S. ^[1] ; Vidal, Benedicto de Campos ^[1]

Afiliação do(s) autor(es)

^[1] Univ Campinas Unicamp, Inst Biol, Dept Struct & Funct Biol, Sao Paulo - Brazil

• Tipo de documento: Artigo Científico
• Fonte: PLoS One; v. 8, n. 1 JAN 18 2013.
• Citações Web of Science: 18

Resumo

Background: Birefringence can reveal much of the morphology, molecular order, heterogeneity of fiber orientation, and nonlinear optical properties of biopolymers such as collagen. However, the detailed characterization of skin collagen fibers using optical anisotropy methods remains elusive. A clear understanding of collagen fiber organization in skin tissues may be important in the interpretation of their structural-functional relationships under normal and pathological conditions. In this study, fiber orientation in collagen bundles (CBs) and their supramolecular organization were examined in rat skin using polarization microscopy and image analysis. Methodology/Principal Findings: Image variations with rotation of the microscope stage and selection of the in-depth focus plane were investigated in unstained sections of varying thicknesses from rat skin fragments. Total birefringence (image analysis) and form and intrinsic birefringence (Senarmont's method) were estimated. Based on the birefringent images, CBs were found to contain intercrossing points with a twisted helical distribution of collagen fibers (chiral elements) and frequently presented circular structures. Collagen fibers were observed to extend from the surface level to deeper planes, creating a 3D-network of oriented intertwined CBs. At least three levels of birefringent brilliance intensity were revealed by image analysis, indicating a heterogeneous spatial organization of the CBs. Slight differences in optical retardations were found for CBs immersed in some of the fluids used in a comparison of 170- and 240-day old rats. Conclusion/Significance: Polarization microscopy studies provide detailed high-quality structural information on rat skin CBs. A 3D-network structure based on image analysis and birefringence compensation for collagen fibers is suggested for CBs. Form and intrinsic birefringence evaluation can reveal differences in the rat skin associated with age at the levels of collagen fiber crystallinity and macromolecular organization. These findings may inspire future studies of the feedback mechanisms by which spatial, bioelectrical and biomechanical information is transmitted from CBs to skin cells. (AU)

• Processo FAPESP: 03/04597-0 - Ordem molecular e organização supramolecular em feixes de colágeno: diferenças com a funcionalidade, como suposto efeito de expressão de patogenia, e contribuição metodológica
• Beneficiário: Benedicto de Campos Vidal
• Modalidade de apoio: Auxílio à Pesquisa - Regular