title: Enhanced intracellular signaling pathway in osteoblasts on ultraviolet lighttreated hydrophilic titanium.
abstract: Ultraviolet (UV) light treatment of titanium immediately prior to use, or photofunctionalization, reactivates the time-dependent degradation of bioactivity of titanium (biological aging of titanium) and increases its osseointegration capacity beyond the inherent maximal level. Although the initial osteoblast attachment is reportedly enhanced on UV-treated titanium surfaces, the detailed mechanism behind the increase in osseointegration is unknown. This study examined the potential modulation of intracellular signaling pathway in osteoblasts on UV-treated titanium surfaces. Rat bone marrow-derived osteoblasts were cultured on 4-week-old, new, and UV-treated titanium surfaces. The new and UV-treated surfaces were superhydrophilic, whereas the 4-week-old surface was hydrophobic. Although the rate of protein adsorption was similarly increased on the new and UV-treated surfaces compared with the 4-week-old surface, the number of attached cells and their spreading behavior were further enhanced on the UV-treated surface. This additional enhancement was associated with the remarkably upregulated expression of paxillin and phospho-paxillin and exclusive upregulation of Rho GTPase family genes. This study provides with the first molecular evidence of the enhanced initial behavior of osteoblasts on UV-treated titanium surfaces. The enhancement was accentuated and distinct from the new titanium surface with similar hydrophilicity, suggesting that surface properties other than the level of hydrophilicity are responsible.
authors.affiliation: Department of Proshodontics, School of Dentistry, Showa University.
authors.forename: Fuminori
authors.initials: F
authors.lastname: Iwasa
authors.forename: Kazuyoshi
authors.initials: K
authors.lastname: Baba
authors.forename: Takahiro
authors.initials: T
authors.lastname: Ogawa
mesh_terms: D000327:Adsorption; D000818:Animals; D002448:Cell Adhesion; D003599:Cytoskeleton / Q000378:metabolism; D015870:Gene Expression; D057927:Hydrophobic and Hydrophilic Interactions; D042541:Intracellular Space; D008297:Male; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism*; D051419:Paxillin / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction; D013499:Surface Properties; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays; D020741:rho GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D051419:Paxillin; D014025:Titanium; D020741:rho GTP-Binding Proteins