Healing of complement activating Ti implants compared with non-activating Ti in rat tibia.
Recent studies have revealed that ozone ultraviolet (UVO) illumination of titanium (Ti) implants improves bone-implant anchorage by altering the physico-chemical and immune activating properties of the titanium dioxide (TiO(2)) layer. In the present rat tibia model, the authors compared the early events of inflammation and bone formation around UVO-treated Ti and complement activating immunoglobin g (IgG)-coated Ti. Machined Ti and machined Ti coated with a physical vapour-deposited Ti layer were used as references. Screw-shaped test and reference implants were implanted into rat tibia and harvested after 1, 7 and 28 days. Messenger RNA expression of implant adhered cells and peri-implant tissue ~250 μm from the surface were subsequently analysed with regard to IL-1β, TNF-α, osteocalcin, cathepsin K, BMP-2 and PDGF. Separate implants were retrieved after 7 and 28 days for removal torque measurements, and histological staining and histomorphometric analysis of bone area and bone-to-implant contact. While enhanced expression of inflammatory markers, TNF-α and IL-1β, was observed on IgG-coated surfaces throughout the observation time, UVO-treated surfaces indicated a significantly lower early inflammatory response. In the early phases (1 and 7 days), the UVO-treated surfaces displayed a significantly higher expression of osteoblast markers BMP-2 and osteocalcin. In summary, complement activating Ti implants elicited a stronger inflammatory response than UVO-treated Ti, with low complement activation during the first week of healing. In spite of this, the UVO-treated Ti induced only marginally more bone growth outside the implants.
Department of Biomaterials, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden. neco@biomaterials.gu.se
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N
Harmankaya
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K
Igawa
P
P
Stenlund
A
A
Palmquist
P
P
Tengvall
D000818:Animals; D003167:Complement Activation / Q000187:drug effects*; D008297:Male; D008855:Microscopy, Electron, Scanning; D016133:Polymerase Chain Reaction; D019736:Prostheses and Implants; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013977:Tibia / Q000187:drug effects* / Q000378:metabolism; D014025:Titanium / Q000494:pharmacology*; D014466:Ultraviolet Rays; D014945:Wound Healing
D012333:RNA, Messenger; D014025:Titanium