title: Altered composition of bone as triggered by irradiation facilitates the rapid erosion of the matrix by both cellular and physicochemical processes.
abstract: Radiation rapidly undermines trabecular architecture, a destructive process which proceeds despite a devastated cell population. In addition to the 'biologically orchestrated' resorption of the matrix by osteoclasts, physicochemical processes enabled by a damaged matrix may contribute to the rapid erosion of bone quality. 8w male C57BL/6 mice exposed to 5 Gy of Cs(137) γ-irradiation were compared to age-matched control at 2d, 10d, or 8w following exposure. By 10d, irradiation had led to significant loss of trabecular bone volume fraction. Assessed by reflection-based Fourier transform infrared imaging (FTIRI), chemical composition of the irradiated matrix indicated that mineralization had diminished at 2d by -4.3±4.8%, and at 10d by -5.8±3.2%. These data suggest that irradiation facilitates the dissolution of the matrix through a change in the material itself, a conclusion supported by a 13.7±4.5% increase in the elastic modulus as measured by nanoindentation. The decline in viable cells within the marrow of irradiated mice at 2d implies that the immediate collapse of bone quality and inherent increased risk of fracture is not solely a result of an overly-active biologic process, but one fostered by alterations in the material matrix that predisposes the material to erosion.
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, New York, United States of America.
authors.forename: Danielle E
authors.initials: DE
authors.lastname: Green
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Adler
authors.forename: Meilin Ete
authors.initials: ME
authors.lastname: Chan
authors.forename: James J
authors.initials: JJ
authors.lastname: Lennon
authors.forename: Alvin S
authors.initials: AS
authors.lastname: Acerbo
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Miller
authors.forename: Clinton T
authors.initials: CT
authors.lastname: Rubin
mesh_terms: D000818:Animals; D001854:Bone Marrow Cells / Q000378:metabolism; D001862:Bone Resorption / Q000209:etiology* / Q000473:pathology; D001842:Bone and Bones / Q000737:chemistry* / Q000473:pathology / Q000528:radiation effects*; D002113:Calcification, Physiologic / Q000528:radiation effects; D024042:Collagen Type I / Q000097:blood / Q000378:metabolism; D008297:Male; D051379:Mice; D010010:Osteoclasts / Q000502:physiology / Q000528:radiation effects; D010710:Phosphates / Q000737:chemistry; D011506:Proteins / Q000737:chemistry; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D024042:Collagen Type I; D010710:Phosphates; D011506:Proteins