BMP-2 modulates expression of other growth factors in a rat fracture healing model

Recombinant human bone morphogenetic protein-2 (rhbmp-2) is an osteo-inductive reagent that can be used therapeutically to promote spinal arthrodesis and fracture healing. despite its clinical use,the effect of rhbmp-2 on expression of endogenous osteogenic growth factors is poorly described. the goal of this study was to determine if local rhbmp-2 treatment modulates expression of pro-osteogenic growth factors during fracture healing. rat femur fractures were wrapped with control or rhbmp-2 collagen soaked sponge. radiographic observations demon- strated that rhbmp-2 treatment enhanced fracture callus formation and decreased bridging time. expression of fracture site growth factor mrnas was determined by quantitative poly- merase chain reaction. the gene expression data demonstrated that rhbmp-2 treatment significantly increased mrna levels of bmp-2 at day 4,bmp-4 at days 2,4,7,and 10,bmp-7 at day 2,and tnf-α at day 7. treatment with rhbmp-2 was shown to significantly reduce mrna levelsof bmp-2 onday2 and10,tnf-α on day 14,and bmp-6 ondays 2,10,14,and 21.tgfβ-1 was also significantly reduced on days 2 and 21. in conclusion,treatment with rhbmp-2 appears to enhance expression of other osteogenic factors that could contribute to bone formation. © 2014 faculty of health and social studies,university of south bohemia in ceske budejovice. published by elsevier urban & partner sp. z o.o. all rights reserved.