Bioactive Glass Stimulates In Vitro Osteoblast Differentiation and Creates a Favorable Template for Bone Tissue Formation

Abstract

In this study, we have investigated the behavior of fetal rat osteoblasts cultured on bioactive glasses with 55 wt% silica content (55S) and on a bioinert glass (60S) used either in the form of granules or in the form of disks. In the presence of Bioglass granules (55 wt% silica content), phase contrast microscopy permitted step-by-step visualization of the formation of bone nodules in contact with the particles. Ultrastructural observations of undecalcified sections revealed the presence of an electron-dense layer composed of needleshaped crystals at the periphery of the material that seemed to act as a nucleating surface for biological crystals. Furthermore, energy dispersive X-ray (EDX) analysis and electron diffraction patterns showed that this interface contains calcium (Ca) and phosphorus (P) and was highly crystalline. When rat bone cells were cultured on 55S disks, scanning electron microscopic (SEM) observations revealed that cells attached, spread to all substrata, and formed multilayered nodular structures by day 10 in culture. Furthermore, cytoenzymatic localization of alkaline phosphatase (ALP) and immunolabeling with bone sialoprotein antibody revealed a positive staining for the bone nodules formed in cultures on 55S. In addition, the specific activity of ALP determined biochemically was significantly higher in 55S cultures than in the controls. SEM observations of the material surfaces after scraping off the cell layers showed that mineralized bone nodules remained attached on 55S surfaces but not on 60S. X-ray microanalysis indicated the presence of Ca and P in this bone tissue. The 55S/bone interfaces also were analyzed on transverse sections. The interfacial analysis showed a firm bone bonding to the 55S surface through an intervening apatite layer, confirmed by the X-ray mappings.

Behaviour of moderately differentiated osteoblast-like cells cultured in contact with bioactive glasses

“…Numerous studies demonstrated a positive effect of bioactive glasses on attachment, proliferation, differentiation and mineralization of bone cells compared to nonreactive surfaces (Vrouwenvelder et al 1992;Loty et al, 2001). However, in our study, no significant differences in the mRNA expression were found.…”

“…Because of these limitations the search for new alternative strategies for repairing bone defects have been focused on tissue engineering. One of its approaches is the use of material matrices as tem-plates for tissue growth in vitro (Loty et al 2001;ElGhannam et al, 1995;Ducheyne et al, 1994). Once again, bioactive glasses seem to find their place, for they fulfill most of the criteria required for a suitable scaffold to support bone tissue growth, since they are known to enhance proliferation and prevent de-differentiation of osteoblast in vitro (Price et al, 1997;El-Ghannam et al, 1997a,b;Vrouwenvelder et al, 1992;Matsuda and Davies, 1987).…”

Ionic Dissolution Products of NovaBone® Promote Osteoblastic Proliferation via Influences on the Cell Cycle

“…Bioactive materials seem to provide a good scaffold to support osteoblasts. 4 When grafted to the defective bone areas, these bioactive scaffolds will not only stimulate osteoblast production, but as these materials are also biodegradable they should eventually be substituted by newlyproduced bone. 5 Studies have already shown that calcium oxide-silicon dioxide (CaO-SiO 2 )-containing materials, such as bioactive glass, 6 possess excellent bioactivity.…”

Bone tissue engineering by using a combination of polymer/Bioglass composites with human adipose-derived stem cells

“…Indeed, numerous in vivo and in vitro studies have shown that 45S5 Bioglass ® can stimulate bone regeneration (Bosetti et al 2003;Gough et al 2004;Livingston et al 2002;Loty et al 2001;Tsigkou et al 2007;Xynos et al 2000). As a result, Bioglass ® is said to be both osteoproductive and osteoconductive.…”