The Effect Of VEGF On Bone Healing After Sympathetic Denervation

Objective:Bone remodeling is closely connected with angiogenesis. Emerging research suggests sympathetic nervous system(SNS) plays an important role in new bone formation and bone remodeling.The aim of this study was to evaluate the possible mechanism of angiogenesis during bone healing regulated by sympathetic nervous.Materials and Methods:A surgical excise of unilateral superior cervical ganglion was used to establish the sympathetic denervation model. Blepharoptosis in SCGx side and the immunohistochemistry detection were used to check the success of model establishment. The first maxillary molars were extracted one week after the SCGx in both SCGx and contralateral sham-operation side. Specimens in the extraction socket were collected at 1,3,7,14 and 21 days’ time points. CD31 and VEGF expression were evaluated by immunohistochemical technique. Counting of endothelial cells and the measurement of average optical density(AOD) values of VEGF in the bottom, middle, top third of tooth socket at each time points were performed respectively.Results:Blepharoptosis showed up after SCGx. Superior cervical ganglion had positive expression of PGP9.5, NPY and TH by immunohistochemical staining.The number of endothelial cells in SCGx group was higher when compared to CG group at all time points. CD 31-positive staining endothelial cells in SCGx group had significant difference compared with that in CG group at 3, 7, 14 days’-time points(p<0.05), and no significantly differences were showed at 1, 21days’-time points(p>0.05).The datas of AOD values of VEGF showed:1)At the bottom third of the sockets: The VEGF level in SCGx group was a little higher when compared to CG group at 1 day time point.But the difference was not statistically significant(P> 0.05). SCGx group had significant higher VEGF-positive staining endothelial cells when compared with CG group at 3, 7and 14 days’-time points(p<0.05),whereas no significant difference was showed at 21 days’ time points(P> 0.05).2) At the middle third of the sockets: There was no statistically significant difference between the two groups at 1 day time point(P> 0.05). But VEGF expression in SCGx group showed significant higher compared with CG group at 3, 7, 14 and 21 days’-time points(p<0.05).3) At the top third of the sockets: VEGF expression in SCGx group had no significant difference compared with CG group at 1 and 3 days’-time points(p>0.05).But at the 7, 14 and 21 days’ time points, the difference had statistically significant(p<0.05).4)In the whole sockets: VEGF expression in SCGx group had significant difference compared with that in CG group at 3,7,14 and 21 days’-time points(p<0.05),and no significantly differences at 1 day time point(p>0.05).5) In CG group: VEGF expression had significant difference at 3, 7 and 21 days’-time points(p<0.05) among the bottom,middle,top third of tooth socket, but no significantly differences were showed at 1 and 14 days’-time points(p>0.05).6)In SCGx group: VEGF expression had significant difference at 1, 3,7 and 21 days’-time points(p<0.05) among the bottom,middle,top third of tooth socket,and no significantly differences were showed at 14 days’-time point(p>0.05).Conclusion:It was concluded that sympathetic denervation can contribute to new bone formation and bone remodeling by increasing angiogenesis and promoting the expression of VEGF during the bone healing.