Tobramycin promotes fracture healing by upregulating expressions of ALP and RUNX2 proteins through activating Wnt/β-catenin pathway

Abstract

To explore effect of tobramycin (TOB) on healing of femoral fractures in rats. Totally 32 male sprague-dawley (SD) rats were selected and randomly divided into sham group (group A), fracture group (group B), fracture with TOB group (group C) and fracture + TOB + IWR-1 group (group D), 8 rats in each group. Close femoral fracture model in rats were established in group B, C and D, group A was sham operation without otherwise process. Group D was intraperitoneal injected 100 μl (8 μM) of Wnt pathway inhibitor IWR-1-endo (IWR-1) before molding at 1 day. At 1 day after molding, 100 μl (100 μM) of TOB was intraperitoneally injected into group C and D at once a day for 7 days. At 7 weeks after modling, fracture healing of group B, C and D were observed by X-ray, Western blotting was appilied to detect alkaline phosphatase(ALP) and Runt related transcription factor 2 (RUNX2) and β-catenin of Wnt passway. X-ray results showed fracture line disappeared, callus formation and fracture healing well in group C compared with begning of molding; while a little fracture line, callus formation and fracture malunion in group B and d could be seen. Western blotting results showed ALP, RUNX2 and expression of β-catenin in group B, C and D were higher than that of group A (P<0.05), while ALP, RUNX2 and β-catenin expression in group C was significantly higher than that of group B and D (P<0.05). After administration of pathway inhibitor IWR-1, there were no significance difference in ALP, RUNX2 and β-catenin protein expression between group D and group B (P>0.05). Tobramycin could promote osteoblast differentiation and fracture healing by stimulating Wnt / β-catenin signaling pathway, up regulating expression of ALP and RUNX2.