Experimental study on the effect of VIP on MVD in the process of fracture healing in rats with high selectiveneurotomy / 医学研究生学报

ABSTRACT

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.