title: UV photoactivation of 7-dehydrocholesterol on titanium implants enhances osteoblast differentiation and decreases Rankl gene expression.
abstract: Vitamin D plays a central role in bone regeneration, and its insufficiency has been reported to have profound negative effects on implant osseointegration. The present study aimed to test the in vitro biological effect of titanium (Ti) implants coated with UV-activated 7-dehydrocholesterol (7-DHC), the precursor of vitamin D, on cytotoxicity and osteoblast differentiation. Fourier transform infrared spectroscopy confirmed the changes in chemical structure of 7-DHC after UV exposure. High-pressure liquid chromatography analysis determined a 16.5±0.9% conversion of 7-DHC to previtamin D(3) after 15min of UV exposure, and a 34.2±4.8% of the preD(3) produced was finally converted to 25-hydroxyvitamin D(3) (25-D(3)) by the osteoblastic cells. No cytotoxic effect was found for Ti implants treated with 7-DHC and UV-irradiated. Moreover, Ti implants treated with 7-DHC and UV-irradiated for 15min showed increased 25-D(3) production, together with increased ALP activity and calcium content. Interestingly, Rankl gene expression was significantly reduced in osteoblasts cultured on 7-DHC-coated Ti surfaces when UV-irradiated for 15 and 30min to 33.56±15.28% and 28.21±4.40%, respectively, compared with the control. In conclusion, these findings demonstrate that UV-activated 7-DHC is a biocompatible coating of Ti implants, which allows the osteoblastic cells to produce themselves active vitamin D, with demonstrated positive effects on osteoblast differentiation in vitro.
authors.affiliation: Department of Fundamental Biology and Health Sciences, Research Institute on Health Sciences (IUNICS), University of Balearic Islands, Spain.
authors.forename: M
authors.initials: M
authors.lastname: Satué
authors.forename: C
authors.initials: C
authors.lastname: Petzold
authors.forename: A
authors.initials: A
authors.lastname: Córdoba
authors.forename: J M
authors.initials: JM
authors.lastname: Ramis
authors.forename: M
authors.initials: M
authors.lastname: Monjo
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002113:Calcification, Physiologic / Q000187:drug effects / Q000235:genetics; D002452:Cell Count; D002454:Cell Differentiation / Q000187:drug effects* / Q000235:genetics; D002460:Cell Line; D048430:Cell Shape / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002762:Cholecalciferol / Q000494:pharmacology; D020099:Coated Materials, Biocompatible / Q000494:pharmacology; D003684:Dehydrocholesterols / Q000528:radiation effects*; D005786:Gene Expression Regulation / Q000187:drug effects / Q000528:radiation effects; D051379:Mice; D006899:Mixed Function Oxygenases / Q000235:genetics / Q000378:metabolism; D010006:Osteoblasts / Q000166:cytology* / Q000187:drug effects / Q000201:enzymology / Q000528:radiation effects; D019736:Prostheses and Implants; D053245:RANK Ligand / Q000235:genetics* / Q000378:metabolism; D017550:Spectroscopy, Fourier Transform Infrared; D013997:Time Factors; D014025:Titanium / Q000494:pharmacology*; D014466:Ultraviolet Rays
chemical_list: D020099:Coated Materials, Biocompatible; D003684:Dehydrocholesterols; D053245:RANK Ligand; D002762:Cholecalciferol; C016705:7-dehydrocholesterol; D014025:Titanium; D006899:Mixed Function Oxygenases; D000469:Alkaline Phosphatase