Chondrogenic Differentiation of Stem Cells on Titanium

Objectives: The aim of this study was to determine the effect of immobilized collagen II and BMP-2 on titanium on the differentiation of human bone marrow-derived mesenchymal stem cells (BM-MSC) into chondrocytes.
Methods: Titanium disks were oxidized by immersion in solution of 8.8 M H₂0₂/0.1 M HCl. Then, the disks were treated with 5 wt % 3-glycidoxypropyltrimethoxysilane (GSP) and coated with either collagen II or BMP-2 (n=6). Human bone marrow-derived mesenchymal stem cells (BM-MSC) (ATCC PCS-500-012) were cultured in cell growth medium (DMEM) and were seeded on the titanium disks. Chondrocyte differentiation medium (ATCC PCS-500-051) was supplied to the cell cultures to promote chondrogenic differentiation. After 3 weeks, the cells were stained for glycosaminoglycan and its level of expression was recorded with light microscopy. In addition, the samples were examined with the Scanning Electron Microscopy. In a subsequent experiment, two new sets of disks coated with either collagen II or BMP-2 were seeded with BM-MSCs and cultured in differentiation media supplemented with 50mg/ml of a Carya plant extract (096-P).
Results: Safranin O staining revealed low quantities of glycosaminoglycan on titanium disks that were treated with either collagen II or BMP-2 in comparison with untreated controls (n=6). SEM images revealed limited evidence of bone marrow stem cell differentiation on those disks. When the differentiation media was supplemented with 096-P, however, chondrogenic differentiation was significantly increased.
Conclusions: Collagen II and BMP-2 treatments on oxidized titanium surfaces promotes mesenchymal stem cell and their differentiation into chondrocytes when supplemented with Carya plant extract (096-P).