BACKGROUND:Stromal cel derived factor-1 (SDF-1)/chemokine receptor 4 (CXCR-4) biological axis plays a chemotactic role in a variety of cel s, making it possible to regulate the regeneration of a variety of tissues. Whether the bidogical is involved in bone morphogenetic protein-2 (BMP-2)-induced homing of bone marrow mesenchymal stem cel s, however, is stil unclear.
OBJECTIVE:To study the role of SDF-1/CXCR4 signaling pathway in BMP-2-induced migration of mouse bone marrow mesenchymal stem cel s.
METHODS:Bone marrow mesenchymal stem cel s in logarithmic growth were selected and intervened with SDF-1 (0, 50, 100 and 200μg/L), BMP-2 (0, 50, 100 and 200μg/L) and AMD3100 (50μg/L) to induce cel migration detected by Transwel method.
RESULTS AND CONCLUSION:The migration of bone marrow mesenchymal stem cel s was closely related to SDF-1 and BMP-2, and proportional to the concentration of both SDF-1 and BMP-2. When SDF-1 and BMP-2 were used jointly, the number of migrated cel s was increased significantly, and highest number of migrated cel s was obtained at 200μg/L. Moreover, these migrated cel s showed a nest-like distribution under microscopy. AMD3100 as an inhibitor markedly suppressed the migration of bone marrow mesencnymal stem cel s induced by BMP-2, but the number of migrated cel s was likely to increase with the increasing concentration of BMP-2 that exceeded a specific value. Overal , our findings show that SDF-1/CXCR4 signaling pathway is an important pathway in BMP-2-induced migration of bone marrow mesenchymal stem cel s.

Objective To systematically review the clinical efficacy and complications of in-tramedullary nailing (IMN) versus plating for distal tibia fractures in adults. Methods A comprehensive search was conducted for the randomized controlled trials from January 2005 to October 2016 on the IMN versus plating for distal tibia fractures in The Cochrane Library, Springer, Pubmed, Medline Embase, CNKI, Wanfang Data and manually as well. The quality of the included literature was evaluated accordingly. RevMan5.3 provided by Cochrane was used to analyze the data. Results A total of 7 randomized con-trolled trials (n=514) were included involving 514 participants (IMN: 267; Plating: 247). IMN achieved a significantly lower superficial infection incidence [MD=2.41, 95% CI (1.11, 5.23), P=0.03]. There were no significant differences between IMN and plating in deep infection [MD=1.43, 95% CI (0.51, 4.04), P=0.50], nonunion [MD=1.35, 95% CI (0.56, 2.38), P=0.51], malunion [MD=0.88, 95% CI (0.50, 1.57), P=0.67], delayed union [MD=0.69, 95% CI (0.26, 1.85), P=0.46],or removal of metal work [MD=1.05, 95% CI (0.81, 1.36), P=0.72]. Conclusion Since plating may lead to a significantly higher rate of superficial infection for adult distal tibial fractures than intramedullary nailing, special attention should be paid to aseptic manipulation during plating, and minimally invasive pro-cedures and soft tissue protection measures should be taken as far as possible.