Non-destructive label-free monitoring of collagen gel remodeling using optical coherence tomography.
Matrix remodeling plays a fundamental role in physiological and pathological processes, as well as in tissue engineering applications. In this paper, optical coherence tomography (OCT), a non-destructive optical imaging technology, was used to image collagen gel remodeling by smooth muscle cells (SMCs). The optical scattering properties of collagen-SMC gels were characterized quantitatively by fitting OCT data to a theoretical model. Matrix remodeling over 5 days produced a 10-fold increase in the reflectivity of the collagen gels, corresponding to a decrease in scattering anisotropy from 0.91 to 0.46. The increase in reflectivity was corroborated in confocal mosaic images. Blocking matrix degradation in collagen-SMC gels with doxycycline, a non-specific matrix metalloproteinases (MMPs) inhibitor, impeded the decrease in scattering anisotropy and resulted in few macroscopic signs of remodeling. Causing matrix degradation in acellular gels with a 3 h treatment of MMP-8 (collagenase 2) partially mimicked the decrease in anisotropy measured in collagen-SMC gels after 5 days. These results suggest that the decrease in scattering anisotropy in the collagen-SMC gels was due to MMP activity that degrades collagen fibrils into smaller fragments.
Levitz
David
D
Department of Biomedical Engineering, Oregon Health & Science University, 3303 SW Bond Ave, Mailcode CH13B, Portland, OR 97239, USA.
Hinds
Monica T
MT
Ardeshiri
Ardi
A
Hanson
Stephen R
SR
Jacques
Steven L
SL
D000818:Animals; D016880:Anisotropy; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D002478:Cells, Cultured; D003094:Collagen / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure; D017364:Collagenases / Q000378:metabolism; D004318:Doxycycline / Q000494:pharmacology; D005782:Gels / Q000737:chemistry / Q000378:metabolism*; D009131:Muscle, Smooth, Vascular / Q000166:cytology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000648:ultrastructure; D010215:Papio; D041623:Tomography, Optical Coherence / Q000379:methods
D000900:Anti-Bacterial Agents; D005782:Gels; D003094:Collagen; D017364:Collagenases; D004318:Doxycycline