title: Castor oil polymer induces bone formation with high matrix metalloproteinase-2 expression.
abstract: The aim of this study was to evaluate the modulation of matrix metalloproteinase-2 (MMP-2) and -9 (MMP-9) expression in newly formed bone tissue at the interface between implants derived from castor oil (Ricinus communis) polymer and the tibia medullary canal. Forty-four rabbits were assigned to either Group 1 (n = 12; control) or Group 2 (n = 30), which had the tibial medullary canals reamed bilaterally and filled with polymer. CT scans showed no space between the material surface and the bone at the implant/bone marrow interface, and the density of the tissues at this interface was similar to the density measured of other regions of the bone. At 90 days postimplantation, the interface with the polymer presented a thick layer of newly formed bone tissue rich in osteocytes. This tissue exhibited ongoing maturation at 120 and 150 days postimplantation. Overall, bone remodeling process was accompanied by positive modulation of MMP-2 and low MMP-9 expression. Differently, in control group, the internal surface close to the medullary canal was lined by osteoblasts, followed by a bone tissue zone with few lacunae filled with osteocytes. Maturation of the tissue of the medullary internal surface occurred in the inner region, with the bone being nonlamellar.
authors.affiliation: Department of Chemistry and Molecular Physics, Institute of Chemistry of São Carlos, University of São Paulo, Brazil.
authors.forename: Wallace Rocha
authors.initials: WR
authors.lastname: Saran
authors.forename: Gilberto Orivaldo
authors.initials: GO
authors.lastname: Chierice
authors.forename: Raquel Assed Bezerra
authors.initials: RA
authors.lastname: da Silva
authors.forename: Alexandra Mussolino
authors.initials: AM
authors.lastname: de Queiroz
authors.forename: Francisco Wanderley Garcia
authors.initials: FW
authors.lastname: Paula-Silva
authors.forename: Léa Assed Bezerra
authors.initials: LA
authors.lastname: da Silva
mesh_terms: D000818:Animals; D016723:Bone Remodeling / Q000187:drug effects; D018786:Bone Substitutes / Q000737:chemistry / Q000494:pharmacology*; D002368:Castor Oil / Q000737:chemistry / Q000494:pharmacology*; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects*; D008297:Male; D020778:Matrix Metalloproteinase 2 / Q000096:biosynthesis*; D020780:Matrix Metalloproteinase 9 / Q000096:biosynthesis; D010012:Osteogenesis / Q000187:drug effects*; D011108:Polymers / Q000737:chemistry / Q000494:pharmacology*; D011817:Rabbits; D011859:Radiography; D013977:Tibia / Q000000981:diagnostic imaging / Q000378:metabolism; D013997:Time Factors; D015898:Tomography Scanners, X-Ray Computed
chemical_list: D018786:Bone Substitutes; D011108:Polymers; D002368:Castor Oil; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9
keywords: biomaterials; biomineralization; castor oil (Ricinus communis) polyurethane; computed tomography; matrix proteins; mechanisms