续骨丹对调节胫骨骨不连大鼠CD34和VEGF增强骨修复的影响

目的：探讨续骨丹外敷疗法对胫骨骨不连大鼠CD34细胞和血管内皮生长因子(vascular endothelial growth factor, VEGF)的影响，探讨续骨丹修复胫骨骨不连潜在的效应机制。方法：将60只SD雄性大鼠随机分为模型对照组，续骨丹低、中、高剂量组(25、75,150 mg/kg)，经皮神经电刺激疗法(transcutaneous electrical nerve stimulation, TENS)组和中剂量+TENS组，每组10只。采用胫骨截骨法制备大鼠胫骨骨不连模型。分别在造模8周后，干预第4、8周后通过X射线、苏木素-伊红(HE)染色法观察骨组织形态变化；运用免疫组织化学法检测骨损伤区CD34和VEGF分布、定位情况。结果：与模型对照组相比，高剂量组和中剂量+TENS组断骨两端骨痂大部分桥接，皮质间隙消失，断骨被新生骨小梁覆盖，骨折损伤区纤维组织明显减少。与模型对照组相比，续骨丹高、中、低剂量组、TENS、中剂量+TENS组中CD34和VEGF的表达水平显著升高。中剂量+TENS组的CD34和VEGF表达水平与续骨丹高剂量组相似，续骨丹低剂量组中CD34和VEGF表达水平显著低于续骨丹中剂量组和TENS组。结论：续骨丹外敷疗法可通过调节CD34和VEGF的表达，改善局部血流供应，促进骨重建和骨不连愈合。

Effect of Xugu Dan on Regulating CD34 and VEGF to Enhance Bone Repair in Rats with Tibial Nonunion

Objective:To investigate the effect of Xugu Dan external application on CD34 cell and vascular endothelial growth factor(VEGF) in rats with tibial nonunion,and to explore its potential mechanism in repairing tibia nonunion.Methods:60 SD male rats were randomly divided into the model group,the Xugu Dan groups of low-dose,medium-dose and high-dose(25 mg/kg,75 mg/kg,150 mg/kg),the transcutaneous electrical nerve stimulation(TENS) group and the medium-dose plus TENS group,with 10 rats in each group.Tibia nonunion model was induced by the method of tibia osteotomy in rats.Morphological changes of bone tissues were observed by X-ray and HE staining after 8 weeks of modeling,and after 4 weeks and 8 weeks of intervention.Distributions and localizations of CD34 and VEGF around bone injury area were detected by immunohistochemical method.Results:Compared with those in the model group,most of the callus at both ends of the fracture were bridged,the cortical space disappeared,the fracture was covered by the new bone trabecula,and the fibrous tissue in the fracture injury area was significantly reduced in the high-dose group and in the medium-dose plus TENS group.Compared with those in the model control group,the expressions of CD34 and VEGF were significantly increased in the Xugu Dan groups of high-dose,medium-dose and low-dose,the TENS group,the medium-dose plus TENS group;there were no statistical differences in the expressions of CD34 and VEGF between the medium-dose plus TENS group and the high-dose group;the expressions of CD34 and VEGF were significantly lower in the low-dose group than those in medium-dose plus TENS group.Conclusion:External application of Xugu Dan can improve the local blood supply,promote bone reconstruction and nonunion healing by regulating the expressions of CD34 and VEGF.