背景：研究已经证实，力学刺激能够促进骨折的愈合。但是，跑步锻炼所产生的力学刺激能否增加骨材料的骨传导性和促进骨缺损的愈合尚不清楚。 目的：观察跑步锻炼所产生的间接力学刺激对骨缺损愈合和骨材料成骨性能的影响。 方法：在12周龄SD大鼠左股骨远端制作一个直径3 mm、高3 mm的缺损，然后在缺损内塞入同等大小的硫酸钙支架材料。实验组于术后1周开始以10 m/min，45 min/d，5 d/周的策略进行跑步锻炼，持续3周；对照组不给予跑步锻炼。 结果与结论：通过micro-CT分析得到，术后1周时，实验组和对照组的骨缺损内已经有少量的新骨形成。在2，3，4周时，实验组骨缺损内新骨生成量明显高于对照组，差异有显著性意义(P<0.05)。在4周时，组织学切片结果也说明实验组新骨生成情况明显优于对照组。另外，给予跑步锻炼之后，实验组骨缺损内生成的新骨骨密度高于对照组，但差异无显著性意义(P>0.05)。结果表明，适度的跑步锻炼确实能够增加骨材料的成骨性能和加速骨缺损的愈合。%BACKGROUND:It is wel-known that mechanical stimulation could promote fracture healing. However, what kind of mechanical stimulation induced by treadmil exercise can increase the bone conductibility of bone material and promote the healing of bone defect is stil unclear. OBJECTIVE:To evaluate the influence of indirect mechanical stimulation produced by treadmil exercise on bone defect healing and osteogenesis of bone materials. METHODS:Sprague-Dawley rats at 12 weeks old were used in this study to establish a bone defect of 3 mm in diameter and height at the left distal femur. Afterwards, calcium sulphate scaffolds were implanted into the defects. The rats were divided into treadmil exercise group and control group. Treadmil exercise was began at 1 week postoperatively, 10 m/min, 45 minutes per day, 5 days per week, for 3 weeks. Control group did not receive any exercise. Micro-computed tomography was used to determine bone formation in the bone defects at 1, 2, 3, and 4 weeks after surgery. The sections of left distal femur were subject to hematoxylin-eosin staining, the new bone formation and degradation of bone materials in the bone defects were observed. RESULTS AND CONCLUSION:Micro-CT analysis showed that, a smal amount of new bone formed in both treadmil exercise group and control group at 1 week after surgery. In treadmil exercise group, new bone formation was significantly higher than the control group at 2, 3, 4 weeks (P<0.05). At 4 weeks, histological results also confirmed the difference of new bone formation in bone defect between treadmil exercise group and control group. In addition, bone mineral density of treadmil exercise group was higher than that of control group at 2, 3, 4 weeks, but no significant difference was found (P>0.05). The results suggest that moderate treadmil exercise could promote bone defect healing and enhance osteoconductivity of bone substitute.
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