[doi: 10.5505/2017ichc.PP-02]Histological Evaluation of Combined Effect of Parathyroid Hormone and Strontium Ranelate on Calvarial Bone Healing in Ovariectomized RatsFunda Göker1, Erdal Cevher2, Selim Ersanlı1, Emine Elif Güzel Meydanlı3, Halim Işsever4, Deniz Morina2, Beyhan Ömer5, Tuğba Ekiz Yılmaz3, Elmire Dervişoglu5, Volkan Arısan12Department of Pharmaceutic Technology, Istanbul University Faculty of Pharmacy, Istanbul, Turkey 3Department of Histology and Embriology, Istanbul University Cerrahpasa Faculty of Medicine, Istanbul, Turkey 4Department of Public Health, Istanbul University Istanbul Faculty of Medicine, Istanbul, Turkey 5Department of Biochemistry, Istanbul University Istanbul Faculty of Medicine, Istanbul, Turkey Introduction&OBJECTIVES: Parathyroid hormone (PTH) enhances healing of bone. Strontium ranelate (SR) is an antiresorptive agent that increases bone formation. Reports about combined effects of PTH plus SR on local bone regeneration in state of osteoporosis are limited. This study searched the feasibility of using PTH and SR in combination to promote local bone repair of critical sized calvarial defects on ovariectomized rats. Materials&METHODS: PTH and/or SR containing poloxamer (px) implant tablets with/without chitosan microparticles (mp) formed by crosslinking with tripolyphosphate as carriers were delivered to calvarial defects on rats. After bilateral ovariectomies, defects were created unilaterally on parietal bones of the animals and were grafted with suitable implant tablets. The treatment groups were as follows; (1) empty defects, (2) poloxamer (px)+chitosan microparticles (mp), (3) SR+px, (4) PTH+px, (5) PTH+px+mp, (6) PTH+SR+px, (7) PTH+SR+px+mp. Samples were obtained after sacrification at 4 and 8 weeks, stained with Hematoxylin-Eosin and Masson trichrome for histological and histomorphometrical evaluation of new bone formation and tissue response to biomaterial. Data were subjected to statistical analysis. RESULTS: The quantitive and qualitative histological analysis revealed that calvarial defects treated with PTH+SR combinations showed statistically significant greater new bone formation than either treatment alone at both time intervals. When PTH is used alone, new bone formation promoted at 4 weeks but its efficiency declined at 8 weeks. On the other hand there was no positive effect of SR on bone formation at 4 or 8 weeks. Low tissue responses supported the good biocompability of chitosan/poloxamer scaffolds. CONCLUSION: This present study demonstrated that PTH and SR combinations may have potential benefits to be considered as bone graft material to enhance bone healing of maxillofacial defects especially in compromised bone healing conditions. |