title: Bone formation induced by strontium modified calcium phosphate cement in critical-size metaphyseal fracture defects in ovariectomized rats.
abstract: The first objective was to investigate new bone formation in a critical-size metaphyseal defect in the femur of ovariectomized rats filled with a strontium modified calcium phosphate cement (SrCPC) compared to calcium phosphate cement (CPC) and empty defects. Second, detection of strontium release from the materials as well as calcium and collagen mass distribution in the fracture defect should be targeted by time of flight secondary ion mass spectrometry (TOF-SIMS). 45 female Sprague-Dawley rats were randomly assigned to three different treatment groups: (1) SrCPC (n = 15), (2) CPC (n = 15), and (3) empty defect (n = 15). Bilateral ovariectomy was performed and three months after multi-deficient diet, the left femur of all animals underwent a 4 mm wedge-shaped metaphyseal osteotomy that was internally fixed with a T-shaped plate. The defect was then either filled with SrCPC or CPC or was left empty. After 6 weeks, histomorphometric analysis showed a statistically significant increase in bone formation of SrCPC compared to CPC (p = 0.005) and the empty defect (p = 0.002) in the former fracture defect zone. Furthermore, there was a statistically significant higher bone formation at the tissue-implant interface in the SrCPC group compared to the CPC group (p < 0.0001). These data were confirmed by immunohistochemistry revealing an increase in bone-morphogenic protein 2, osteocalcin and osteoprotegerin expression and a statistically significant higher gene expression of alkaline phosphatase, collagen10a1 and osteocalcin in the SrCPC group compared to CPC. TOF-SIMS analysis showed a high release of Sr from the SrCPC into the interface region in this area compared to CPC suggesting that improved bone formation is attributable to the released Sr from the SrCPC.
authors.affiliation: Laboratory of Experimental Trauma Surgery, Justus-Liebig-University, Giessen, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Thormann
authors.forename: Seemun
authors.initials: S
authors.lastname: Ray
authors.forename: Ursula
authors.initials: U
authors.lastname: Sommer
authors.forename: Thaqif
authors.initials: T
authors.lastname: Elkhassawna
authors.forename: Tanja
authors.initials: T
authors.lastname: Rehling
authors.forename: Marvin
authors.initials: M
authors.lastname: Hundgeburth
authors.forename: Anja
authors.initials: A
authors.lastname: Henß
authors.forename: Marcus
authors.initials: M
authors.lastname: Rohnke
authors.forename: Jürgen
authors.initials: J
authors.lastname: Janek
authors.forename: Katrin S
authors.initials: KS
authors.lastname: Lips
authors.forename: Christian
authors.initials: C
authors.lastname: Heiss
authors.forename: Gudrun
authors.initials: G
authors.lastname: Schlewitz
authors.forename: Gabor
authors.initials: G
authors.lastname: Szalay
authors.forename: Matthias
authors.initials: M
authors.lastname: Schumacher
authors.forename: Michael
authors.initials: M
authors.lastname: Gelinsky
authors.forename: Reinhard
authors.initials: R
authors.lastname: Schnettler
authors.forename: Volker
authors.initials: V
authors.lastname: Alt
mesh_terms: D000469:Alkaline Phosphatase / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D001843:Bone Cements / Q000494:pharmacology*; D052006:Bone Morphogenetic Protein Receptors, Type II / Q000235:genetics / Q000378:metabolism; D002130:Calcium Phosphates / Q000494:pharmacology*; D023381:Endpoint Determination; D005260:Female; D005269:Femur / Q000187:drug effects / Q000601:surgery; D050723:Fractures, Bone / Q000188:drug therapy*; D007150:Immunohistochemistry; D015675:Osteocalcin / Q000235:genetics / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects*; D053244:Osteoprotegerin / Q000235:genetics / Q000378:metabolism; D010052:Ovariectomy; D051381:Rats; D017207:Rats, Sprague-Dawley; D013324:Strontium / Q000494:pharmacology*
chemical_list: D001672:Biocompatible Materials; D001843:Bone Cements; D002130:Calcium Phosphates; D053244:Osteoprotegerin; D015675:Osteocalcin; C020243:calcium phosphate; C498220:Bmpr2 protein, rat; D052006:Bone Morphogenetic Protein Receptors, Type II; D000469:Alkaline Phosphatase; D013324:Strontium
keywords: Biomaterial; Bone; Calcium phosphate; Fracture; Strontium