高选择性神经切断的大鼠骨折愈合过程中血管活性肠肽对微血管密度的影响

摘要

目的 血管活性肠肽(VIP)调控骨折愈合的作用机制和信号通路机制不明,文章通过建立选择性切断大鼠感觉/运动神经联合胫骨骨折的动物模型,探讨周围神经损伤后其骨折愈合过程中VIP对微血管密度(MVD)的影响. 方法 将60只SD实验大鼠随机数字表法分成3组:胫骨骨折组,感觉神经切断组(胫骨骨折+后根感觉神经切断组),运动神经切断组(胫骨骨折+前根运动神经切断组),每组20只.3组大鼠在模型建立后的1、2、3、4周处死大鼠,骨痂标本在骨折处周围5mm处获取,观察VIP的表达及MVD的变化规律. 结果 组织学观察显示,感觉神经切断组在4个时相点均较胫骨骨折组和运动神经切断组新生骨小梁成熟度低;免疫组化结果显示,与第2、3周感觉神经切断组骨痂VIP平均光密度(0.156±0.015、0.163±0.012)比较,胫骨骨折组(0.216±0.012、0.223±0.010)、运动神经切断组(0.198±0.014、0.212±0.016)明显升高(P<0.05).免疫组化检测骨痂MVD发现,与感觉神经切断组第2、3周骨痂MVD平均密度(26.4±2.2、32.3±2.0)比较,胫骨骨折组(38.2±2.3、40.6±2.6)、运动神经切断组(36.6±2.2、38.5±2.1)明显升高(P<0.05).术后第2、3、4周,与感觉神经切断组比较,运动神经切断组和胫骨骨折组胫骨湿重明显升高(P<0.05),其中以2周时增加幅度最为显著. 结论 失感觉神经支配比失运动神经支配对骨痂内MVD的形成、骨痂成熟度、骨折愈合速度的影响更为明显.%Objective The mechanism and signaling mechanisms of fracture healing by vasoactive intestinal peptide (VIP) regulating are not clear.We established an selective cut off sensory/motor nerve combined with tibial fracture rat model to study the effects of VIP and microvessel density(MVD) during the fracture healing process after nerve injury.Methods 60 SD rats were randomly divided into 3 groups: tibial fracture + motor nerve (anterior root) cutting group (group ART);tibial fracture + posterior root (sensory nerve) cutting group (group PRT);tibial fracture group (group SO),and each group were 20.Three groups of rats in the model after the establishment of 1W, 2W, 3W, 4W these time points, were killed.The skeleton specimens were obtained in the vicinity of the fracture 5mm, to observe the expression of VIP and microvessel density of the law of change.Results Histology observation showed: new bone trabecular bone callus maturity of PRT group is lower than SO group and ART group at each time points;the immunohistochemical staining showed that compared with callus VIP average optical density of PRT group at 2w and 3w(0.156±0.015、0.163±0.012), SO group(0.216±0.012、0.223±0.010) and ART group(0.198±0.014、0.212±0.016) increased obviously(P<0.05).The detection of callus MVD indicated that compared with callus MVD average density of PRT group at 2w and 3w(26.4±2.2、32.3±2.0), SO group(38.2±2.3、40.6±2.6) and ART group(36.6±2.2、38.5±2.1) significant increased (P<0.05).At the 2nd, 3rd and 4th week, the wet weight of tibia was significantly increased in group ART and SO compared with group PRT(P<0.05),which increased more significantly at 2 weeks.Conclusion The effect of loss of sensory nerve innervation on the formation of microvessel density, callus maturity and fracture healing rate were more pronounced than loss of motor nerve innervation.