title: Applicability of ToF-SIMS for monitoring compositional changes in bone in a long-term animal model.
abstract: Time-of-flight secondary ion mass spectrometry (ToF-SIMS) is a well-established technique in material sciences but has not yet been widely explored for implementation in life sciences. Here, we demonstrate the applicability and advantages of ToF-SIMS analysis for the study of minerals and biomolecules in osseous tissue. The locally resolved analysis of fragment ions deriving from the sample surface enables imaging and differentiation of bone tissue and facilitates histology on non-stained cross sections. In a rat model, bilateral ovariectomy combined with either a multi-deficiency diet or steroid treatment was carried out to create osteoporotic conditions. We focused our study on the Ca content of the mineralized tissue and monitored its decline. Calcium mass images of cross sections show the progressive degenerative changes in the bone. We observed a decreased Ca concentration in the edge region of the trabeculae and a decline in the Ca/P ratio. Additionally, we focused on the non-mineralized matrix and identified fragment ions that are characteristic for the collagen matrix. We observed trabeculae with wide ranges of non-mineralized collagen for the diet group owing to an impaired mineralization process. Here, the advantage of coeval monitoring of collagen and minerals indicated an osteomalacic model rather than an osteoporotic one.
authors.affiliation: Institute for Physical Chemistry, Justus-Liebig-University of Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany.
authors.forename: Anja
authors.initials: A
authors.lastname: Henss
authors.forename: Marcus
authors.initials: M
authors.lastname: Rohnke
authors.forename: Thaqif
authors.initials: T
authors.lastname: El Khassawna
authors.forename: Parameswari
authors.initials: P
authors.lastname: Govindarajan
authors.forename: Gudrun
authors.initials: G
authors.lastname: Schlewitz
authors.forename: Christian
authors.initials: C
authors.lastname: Heiss
authors.forename: Juergen
authors.initials: J
authors.lastname: Janek
mesh_terms: D000818:Animals; D015519:Bone Density; D002118:Calcium / Q000378:metabolism*; D003094:Collagen / Q000378:metabolism*; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D008159:Lumbar Vertebrae / Q000378:metabolism* / Q000473:pathology; D015663:Osteoporosis, Postmenopausal / Q000378:metabolism* / Q000473:pathology; D010052:Ovariectomy; D010758:Phosphorus / Q000378:metabolism; D051381:Rats; D018629:Spectrometry, Mass, Secondary Ion / Q000379:methods*; D013997:Time Factors
chemical_list: D010758:Phosphorus; D003094:Collagen; D002118:Calcium
keywords: bone imaging; calcium distribution in bone; chemical imaging; collagen; mass spectrometry