Large-scale gene expression analysis of osteoblasts cultured on three different Ti-6Al-4V surface treatments.
To improve implant biocompatibility, we developed a simple cost-effective thermal surface treatment allowing an increase in the oxide layer thickness of a titanium (Ti) alloy used in orthopaedic implants. The goal of this study was to test in vitro the reaction of osteoblasts to the developed surface treatment and to compare it to the osteoblast reaction to two other surface treatments currently used in the practice of implant surgery. Quantification of osteoblast gene expression on a large scale was used in this study. The kinetics of gene expression over 120 h was followed for 58 genes to quantify the effect of the developed surface treatment. Twenty eight genes were further selected to compare the effects of surface treatments on osteoblasts. Based on the genes studied, we could propose a general pathway for the cell reaction according to the surface treatments used: (1) metal ion release changes the time course of gene expression in the FAK pathway; (2) once the accumulation of metal ions released from the Ti surface exceeds a threshold value, cell growth is diminished and apoptosis may be activated; (3) PTK up-regulation is also induced by metal ion release; (4) the expression of Bcl-2 family and Bax may suggest that metal ions induce apoptosis. The developed treatment seems to increase the Ti-6Al-4V biocompatibility as highlighted by the lower impact of this treatment by the different pathways studied, on the lower inflammatory reaction that could be induced, as well as by the lower induced osteoblast apoptosis compared to the two other surface treatments.
Bone Bioengineering Group, Institute for Biomedical Engineering, Swiss Federal Institute of Technology, Lausanne, Switzerland.
Ching-Hsin
CH
Ku
Martin
M
Browne
Peter J
PJ
Gregson
Jacques
J
Corbeil
Dominique P
DP
Pioletti
D000497:Alloys; D018929:Cell Culture Techniques / Q000379:methods*; D002478:Cells, Cultured; D020099:Coated Materials, Biocompatible; D005260:Female; D051521:Fibroblast Growth Factor 5; D005346:Fibroblast Growth Factors / Q000378:metabolism; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; D020869:Gene Expression Profiling; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008875:Middle Aged; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology*; D019736:Prostheses and Implants; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics; D014025:Titanium / Q000737:chemistry*; D051020:bcl-X Protein
D000497:Alloys; C494811:BCL2L1 protein, human; D020099:Coated Materials, Biocompatible; C496449:FGF5 protein, human; D019253:Proto-Oncogene Proteins c-bcl-2; D051020:bcl-X Protein; C031462:titanium alloy (TiAl6V4); D051521:Fibroblast Growth Factor 5; D005346:Fibroblast Growth Factors; D007334:Insulin-Like Growth Factor I; D014025:Titanium; D011505:Protein-Tyrosine Kinases; D051417:Focal Adhesion Kinase 1; D051416:Focal Adhesion Protein-Tyrosine Kinases; C496050:PTK2 protein, human; D020928:Mitogen-Activated Protein Kinases