Enhanced osteoprogenitor elongated collagen fiber matrix formation by bioactive glass ionic silicon dependent on Sp7 (osterix) transcription

Venu G. Varanasi, Tetsurou Odatsu, Timothy Bishop, Joyce Chang, Jeremy Owyoung, Peter M. Loomer

Research output: Contribution to journalArticlepeer-review

7 Scopus citations


Bioactive glasses release ions, those enhance osteoblast collagen matrix synthesis and osteogenic marker expression during bone healing. Collagen matrix density and osteogenic marker expression depend on osteogenic transcription factors, (e.g., Osterix (OSX)). We hypothesize that enhanced expression and formation of collagen by Si4+ depends on enhanced expression of OSX transcription. Experimental bioactive glass (6P53-b) and commercial BioglassTM (45S5) were dissolved in basal medium to make glass conditioned medium (GCM). ICP-MS analysis was used to measure bioactive glass ion release rates. MC3T3-E1 cells were cultured for 20 days, and gene expression and extracellular matrix collagen formation was analyzed. In a separate study, siRNA was used to determine the effect of OSX knockdown on impacting the effect of Si4+ on osteogenic markers and matrix collagen formation. Each bioactive glass exhibited similar ion release rates for all ions, except Mg2+ released by 6P53-b. Gene expression results showed that GCM markedly enhanced many osteogenic markers, and 45S5 GCM showed higher levels of expression and collagen matrix fiber bundle density than 6P53-b GCM. Upon knockdown of OSX transcription, collagen type 5, alkaline phosphatase, and matrix density were not enhanced as compared to wild type cells. This study illustrates that the enhancement of elongated collagen fiber matrix formation by Si± depends on OSX transcription.

Original languageEnglish (US)
Pages (from-to)2604-2615
Number of pages12
JournalJournal of Biomedical Materials Research - Part A
Issue number10
StatePublished - Oct 1 2016
Externally publishedYes


  • bioactive glass
  • bone regeneration
  • collagen type I
  • magnesium
  • silicon

ASJC Scopus subject areas

  • Ceramics and Composites
  • Biomaterials
  • Biomedical Engineering
  • Metals and Alloys


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