Molecular biologic comparison of new bone formation and resorption on microrough and smooth bioactive glass microspheres

A1 Journal article (refereed)


Internal Authors/Editors


Publication Details

List of Authors: Itala A, Valimaki VV, Kiviranta R, Ylanen HO, Hupa M, Vuorio E, Aro HT
Publisher: WILEY-LISS
Publication year: 2003
Journal: Journal of Biomedical Materials Research Part B: Applied Biomaterials
Journal acronym: J BIOMED MATER RES B
Volume number: 65B
Issue number: 1
Start page: 163
End page: 170
Number of pages: 8
ISSN: 0021-9304


Abstract

In a recent in vitro study, chemical microroughening of a bioactive glass surface was shown to enhance attachment of MG-63 osteoblastic cells to glass. The current study was designed to delineate the effects of microroughening on the gene expression patterns of bone markers during osteogenesis and new bone remodeling on bioactive glass surface in vivo. With the use of a rat model of paired comparison, a portion of the medullary canal in the proximal tibia was evacuated through cortical windows and filled with microroughened or smooth bioactive glass microspheres. The primary bone-healing response and subsequent remodeling were analyzed at 1, 2, and 8 weeks, respectively, by radiography, pQCT, histomorphometry, BEI-SEM, and molecular biologic analyses. The expression of various genes for bone matrix components (type I collagen, osteocalcin, osteopontin, osteonectin) and proteolytic enzymes (cathepsin K, MMP-9) were determined by Northern analysis of the respective mRNAs. Paired comparison showed significant differences in the mRNAs levels for specific bone matrix components at 2 weeks: osteopontin was significantly higher (p = .01) and osteonectin significantly lower (p = .05) in bones filled with microroughened microspheres than in those filled with smooth microspheres. Bones filled with microrough microspheres also showed significantly increased ratios of cathepsin K and MMP-9 (both markers of osteoclastic resorption) to type I collagen (p = .02 and p = .02, respectively) at 2 weeks and a significantly increased expression of MMP-9 at 8 weeks (p = .05). The pQCT, histomorphometric, and BEI-SEM analyses revealed no significant differences in the pattern of bone-healing response. Based on these results, microroughening of a bioactive glass surface could trigger temporal changes in the expression of specific genes especially by promoting the resorption part of new bone-remodeling processes. Future studies are needed to evaluate if the observed changes of gene expression are directly related to the microrough surface of any biomaterial or are biomaterial specific. (C) 2003 Wiley Periodicals, Inc.


Keywords

gene expression, microrough surface, osteogenesis, rat model

Last updated on 2020-22-01 at 05:04