title: Highlighting the impact of aging on type I collagen: label-free investigation using confocal reflectance microscopy and diffuse reflectance spectroscopy in 3D matrix model.
abstract: During aging, alterations of extracellular matrix proteins contribute to various pathological phenotypes. Among these alterations, type I collagen cross-linking and associated glycation products accumulation over time detrimentally affects its physico-chemical properties, leading to alterations of tissue biomechanical stability. Here, different-age collagen 3D matrices using non-destructive and label-free biophotonic techniques were analysed to highlight the impact of collagen I aging on 3D constructs, at macroscopic and microscopic levels. Matrices were prepared with collagens extracted from tail tendons of rats (newborns, young and old adults) to be within the physiological aging process. The data of diffuse reflectance spectroscopy reveal that aging leads to an inhibition of fibril assembly and a resulting decrease of gel density. Investigations by confocal reflectance microscopy highlight poor-fibrillar structures in oldest collagen networks most likely related to the glycation products accumulation. Complementarily, an infrared analysis brings out marked spectral variations in the Amide I profile, specific of the peptidic bond conformation and for carbohydrates vibrations as function of collagen-age. Interestingly, we also highlight an unexpected behavior for newborn collagen, exhibiting poorly-organized networks and microscopic features close to the oldest collagen. These results demonstrate that changes in collagen optical properties are relevant for investigating the incidence of aging in 3D matrix models.
authors.affiliation: MéDIAN-Biophotonique et Technologies pour la Santé, Université de Reims Champagne-Ardenne, CNRS UMR 7369 MEDyC, UFR de Pharmacie, SFR CAP Santé, Reims, France.
authors.forename: Marie
authors.initials: M
authors.lastname: Guilbert
authors.affiliation: CEA, LETI, Minatec Campus, Grenoble, France.
authors.forename: Blandine
authors.initials: B
authors.lastname: Roig
authors.affiliation: Plate-forme Imagerie Cellulaire et Tissulaire, Université de Reims Champagne-Ardenne, Reims, France.
authors.forename: Christine
authors.initials: C
authors.lastname: Terryn
authors.affiliation: MéDIAN-Biophotonique et Technologies pour la Santé, Université de Reims Champagne-Ardenne, CNRS UMR 7369 MEDyC, UFR de Pharmacie, SFR CAP Santé, Reims, France.
authors.forename: Roselyne
authors.initials: R
authors.lastname: Garnotel
authors.affiliation: MéDIAN-Biophotonique et Technologies pour la Santé, Université de Reims Champagne-Ardenne, CNRS UMR 7369 MEDyC, UFR de Pharmacie, SFR CAP Santé, Reims, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Jeannesson
authors.affiliation: MéDIAN-Biophotonique et Technologies pour la Santé, Université de Reims Champagne-Ardenne, CNRS UMR 7369 MEDyC, UFR de Pharmacie, SFR CAP Santé, Reims, France.|Plate-forme Imagerie Cellulaire et Tissulaire, Université de Reims Champagne-Ardenne, Reims, France.
authors.forename: Ganesh D
authors.initials: GD
authors.lastname: Sockalingum
authors.affiliation: MéDIAN-Biophotonique et Technologies pour la Santé, Université de Reims Champagne-Ardenne, CNRS UMR 7369 MEDyC, UFR de Pharmacie, SFR CAP Santé, Reims, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Manfait
authors.affiliation: CEA, LETI, Minatec Campus, Grenoble, France.
authors.forename: François
authors.initials: F
authors.lastname: Perraut
authors.affiliation: CEA, LETI, Minatec Campus, Grenoble, France.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Dinten
authors.affiliation: CEA, LETI, Minatec Campus, Grenoble, France.
authors.forename: Anne
authors.initials: A
authors.lastname: Koenig
authors.affiliation: MéDIAN-Biophotonique et Technologies pour la Santé, Université de Reims Champagne-Ardenne, CNRS UMR 7369 MEDyC, UFR de Pharmacie, SFR CAP Santé, Reims, France.|Plate-forme Imagerie Cellulaire et Tissulaire, Université de Reims Champagne-Ardenne, Reims, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Piot
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D024042:Collagen Type I / Q000378:metabolism*; D005109:Extracellular Matrix / Q000737:chemistry / Q000378:metabolism* / Q000648:ultrastructure*; D021621:Imaging, Three-Dimensional / Q000379:methods*; D008297:Male; D018613:Microscopy, Confocal / Q000379:methods*; D008857:Microscopy, Interference / Q000379:methods*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D024042:Collagen Type I
keywords: 3D matrix; ATR infrared imaging; Gerotarget; Type I collagen aging; confocal reflectance microscopy; diffuse reflectance spectroscopy