The effect of titanium surface with nanotopography on the temporal expression of Rad GTPase in osteoblastic cells

Abstract

Titanium (Ti) surfaces with nanotopography may favor osteoblastic differentiation by modulating the synthesis of local factors that act on signaling pathways to regulate bone formation. Some results of our research group have shown that the osteogenic potential of a nanotopography generated by H2SO4/H2O2 treatment involves the modulation of, at least, two intracellular mechanisms regulated by BMPs and Integrins. Recent studies identified the expression and the participation of Ras-related associated with diabetes protein (Ras GTPase, Rad) in the process of osteoblastic differentiation and in bone homeostasis. Considering the relevance of Rad to osteogenesis, we hypothesized that the osteogenic potential of Ti with nanotopography is, at least in part, related to its capacity to modulate the Rad expression. Then, the aim of this study is to evaluate the effect of Ti with nanotopography, compared with machined Ti, on the time course expression of Rad in osteoblastic cells. To test our hypothesis, osteoblastic cell lineage MC3T3-E1, subclone 14, will be cultured on discs of Ti with nanotopography (Ti-Nano) and machined Ti (Ti-Control) and cell responsed will be evaluated for up to 14 days. At days 3, 5, 7, 10 and 14, the gene expression of the bone markers alkaline phosphatase (ALP), RUNX2, osterix, osteocalcin and osteopontin and of the Rad eMatrix Gla Protein (MGP) will be evaluated by real-time PCR. At day 10, the in situ ALP activity will be also evaluated by the Fast red assay. The numerical data will be submitted to the test of adherence to the normal distribution to determine the statistical analysis that should be used. (AU)