中文摘要：

目的探讨外源性的β-NGF在骨缺损愈合过程中对骨改建可能作用机制。方法利用外科手术方法切取SD大鼠颅骨顶部左右两侧的骨质,建立配对大鼠颅骨标准骨缺损局部持续灌注β-NGF给药模型。通过免疫组织化学技术检测骨缺损区组织中BMP-2的表达水平以及特殊染色技术（TRAP染色）检测骨缺损区组织中抗酒石酸碱性磷酸酶的表达水平,通过图像处理软件IPP6.0分别测定两者积分光密度值（IOD）,以探讨BMP-2与破骨细胞活性在β-NGF调节新骨形成和改建过程中的可能作用机制。结果实验组BMP-2免疫组化染色阳性表达水平在14 d时IOD值明显高于对照组,且差异有显著性（P〈0.05）;TRAP染色结果显示：实验组骨吸收的活性在第7,21,28天三个时间点上明显低于对照组,且差异有显著性（P〈0.05）。结论外源性的β-NGF在骨缺损修复过程中具有重要的调节作用,其可能是通过促进BMP-2表达和抑制破骨细胞的活性以抑制骨吸收。

英文摘要：

Objective To explore the mechanism of bone remodeling during the process of bone defect healing via topical application of exogenous β-NGF. Methods Thirty healthy male Sprague-Dawley rats were used in this study. Two5-mm diameter bilateral bone defects were created on the parietal bone. The right side was given 10 μg β-NGF / PBS solution（ experimental group） and the left side was given only PBS solution（ control group） via an osmotic pump for 7 days.Expression levels of BMP-2 and tartrate-resistant alkalin phosphatase（ TRAP） at postoperative 3,7,14,21 and 28 days were detected using immunohistochemical staining and semi-quantitatively analyzed with integral optical density（ IOD）.Results Immunohistochemistry showed that the expression levels of BMP-2（ IOD values） in the experimental group were significantly higher（ P〈0. 05） than that of the control group at postoperative day 14. Special TRAP staining results showed that the activities of osteoclasts in the experimental group was significantly decreased compared with that of the control group（ P〈0. 05） at postoperative day 7,21 and 28. Conclusions The results of this study indicate that topical application of exogenous β-NGF plays an important role in bone remodeling during the process of bone defect healing,which may be through increased production of BMP-2 and inhibition of osteoclast activity.