Osseointegrative effect of rhBMP-2 covalently bound on a titan-plasma-spray-surface after modification with chromosulfuric acid in a large animal bone gap-healing model with the Göttingen minipig

Abstract

BackgroundBone morphogenetic proteins play an important role as osseointegrative factors. It is used widely in orthopedic research and surgery to enhance the osseointegrative potential of implants, e.g., in spinal fusion or alveolar socket augmentation. The aim of the present study was to investigate the benefit of rhBMP-2 on a titan plasma spray (TPS) layer after a special modification with chromosulfuric acid (CSA) at different postoperative times, regarding osseoconduction and osseoinduction.MethodsWe allocated 27 Göttinger minipigs into three groups consisting of nine animals each. They received four dumbbell-shaped implants in the metaphyseal parts of the femora. The implants had a TPS surface with (CSA group) and without a CSA treatment (TPS group). The former received an additional layer of BMP-2 (BMP-2 group). For the assessment of osseointegration after healing periods of 4, 8, and 12 weeks, histomorphometry was applied to undecalcified specimens after staining according to Masson-Goldner. An intravital labeling with different fluorochromes was used in the gap model. A multivariable analysis with repeated measurement design was performed for statistical evaluation.ResultsWe observed several statistical differences in a three-way ANOVA. The comparison between the BMP-2 and the TPS group (two-way ANOVA) showed statistically significant differences in terms of the osseoinduction (osteoid volume), and pronounced for the osseoconduction (bone and osteoid ongrowth), in favor of the BMP-2 group. In the pairwise comparison between BMP-2 and CSA (two-way ANOVA), no statistical significance occurred. The intravital staining with tetracycline, calcein green, and xylenol orange revealed no considerable differences between the groups.ConclusionBMP-2, covalently bound on a CSA-treated TPS surface, has positive effects on the osseointegration in the large animal bone gap-healing model over the observation period of 12 weeks.

Spatiotemporal monitoring of hard tissue development reveals unknown features of tooth and bone development

“…Recently, calcein and xylenol orange administration followed by fluorescent imaging was also used to follow the natural replacement dynamics of gecko teeth (reptiles) ( 45 ). In bone field, the administration of hard tissue–incorporating fluorochromes has been used to observe bone healing after the injury and to assess the integration of artificial implants using wide-field fluorescence imaging ( 46 , 47 ). In addition to these studies, BEE-ST represents a universal approach broadly applicable in variety of species providing a tool to precisely measure the dynamics of hard tissue growth and healing in a three-dimensional perspective.…”