Time-dependent expression of osteoblast marker genes in human primary cells cultured on microgrooved titanium...

This study aimed to investigate the influence of titanium surface-etched microgrooves and ridges on the time-dependent expression of osteoblast marker genes and proteins of human primary cells undergoing osteoblast differentiation.

Fifteen-, 30-, and 60-μm wide, and 3.5- and 10-μm deep-etched microgrooves and ridges were fabricated on titanium substrata using photolithography and subsequent acid etching, and were used as the experimental groups (E15/3.5, E30/10, and E60/10), whereas the smooth and acid-etched titanium were used as the control (NE0 and E0). Time-dependent mRNA and protein expression of type I collagen α1, alkaline phosphatase, runt-related transcription factor 2, osterix, osteocalcin, osteopontin, bone sialoprotein II, and osteonectin after 7, 14, 21, and 28 days of osteogenic culture was analyzed using quantitative real-time PCR, RT-PCR, western blotting, and protein quantitation. Student's t-test, one-way analysis of variance, and Pearson's correlation analysis were used for statistics.

Etched microgrooves and ridges induced significantly lower levels of type I collagen α1 gene expression at day 14, and an extreme increase in osteopontin gene expression at days 21 and 28 compared with smooth control. However, the expression levels of the other osteoblast marker genes and proteins analyzed in this study correspond with previously reported expression patterns of cells on variously modified titanium surfaces during osteoblast differentiation and bone formation.

This study indicates that etched microgrooves and ridges on titanium substrata induce both typical and unique time-dependent expression patterns of the osteoblast marker genes and proteins analyzed in this study.