title: Local application of rhTGF-beta2 enhances peri-implant bone volume and bone-implant contact in a rat model.
abstract: Orthopedic and dental implant fixation depends upon bone regeneration. Growth factors such as transforming growth factor-beta (TGF-beta) have been shown to enhance bone repair and strengthen the mechanical connection between implant and host skeleton in canine models. To provide a platform for studying molecular mechanisms of growth factor stimulated bone regeneration and implant fixation, the present study examined peri-implant bone volume as a response to TGF-beta treatment in a rodent model. The rat femoral ablation model in which an implant is placed in the medullary cavity of the femur was used to examine the dose response to TGF-beta2 applied to the implant (0, 0.1, 1.0, or 10 microg). The study included a total of 40 rats (10 per dose) examined at 28 days. Peri-implant bone volume and bone-implant contact were assessed through microcomputed tomography and implant fixation strength was determined by a mechanical pullout test. Treatment of the implant with 10 microg TGF-beta2 led to a 2-fold increase in bone volume (P<0.001) and a 1.5-fold increase in bone-implant contact (P<0.01) with a trend of increasing fixation strength (non-significant increase of 1.4-fold). TGF-beta2 treatment with 10 microg led to uniform peri-implant bone volume and bone-implant contact along the length of the implant, whereas the other groups had less bone at the mid-point compared to the proximal and distal aspects of the implant. About 50% of the variance in implant fixation strength was explained by a regression model involving both bone-implant contact and peri-implant bone volume.
authors.affiliation: Department of Anatomy and Cell Biology, Rush Medical College, Rush University Medical Center, Chicago, IL 60612, USA.
authors.forename: Aladino
authors.initials: A
authors.lastname: De Ranieri
authors.forename: Amarjit S
authors.initials: AS
authors.lastname: Virdi
authors.forename: Shinji
authors.initials: S
authors.lastname: Kuroda
authors.forename: Susan
authors.initials: S
authors.lastname: Shott
authors.forename: Robert M
authors.initials: RM
authors.lastname: Leven
authors.forename: Nadim J
authors.initials: NJ
authors.lastname: Hallab
authors.forename: Dale R
authors.initials: DR
authors.lastname: Sumner
mesh_terms: D000818:Animals; D001861:Bone Regeneration / Q000187:drug effects*; D001842:Bone and Bones / Q000033:anatomy & histology / Q000737:chemistry; D002130:Calcium Phosphates / Q000737:chemistry; D003692:Delayed-Action Preparations / Q000493:pharmacokinetics; D005269:Femur / Q000601:surgery; D006133:Growth Substances / Q000494:pharmacology; D006882:Hydroxyapatites / Q000737:chemistry; D020007:Implants, Experimental; D008297:Male; D023421:Models, Animal; D051381:Rats; D017207:Rats, Sprague-Dawley; D011994:Recombinant Proteins / Q000494:pharmacology; D033081:Shear Strength; D014025:Titanium / Q000737:chemistry; D014057:Tomography, X-Ray Computed; D016212:Transforming Growth Factor beta / Q000494:pharmacology*; D053781:Transforming Growth Factor beta2
chemical_list: D002130:Calcium Phosphates; D003692:Delayed-Action Preparations; D006133:Growth Substances; D006882:Hydroxyapatites; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; D053781:Transforming Growth Factor beta2; C074950:hydroxyapatite-beta tricalcium phosphate; D014025:Titanium