促红细胞生成素对大鼠即刻再植牙牙髓血运重建的促进作用

Promotion effect of erythropoietin on immediate revascularization of replanted teeth in rats

目的:探讨血管内皮细胞生长因子(VEGF)在大鼠即刻再植牙牙髓愈合过程中的表达,阐明促红细胞生成素(EPO)对大鼠即刻再植牙牙髓血运重建的作用及机制。方法:80只4周龄健康雄性Wistar大鼠随机分为未拔牙组、阴性对照(生理盐水)组、阳性药对照(庆大霉素)组和EPO组,每组20只,各组大鼠拔除的牙齿在其相对应的溶液中浸泡4min后再植,于再植术后3、7、14、21和28d分别处死4只大鼠,制作术区标本,行HE染色观察各组大鼠在不同时间段内再植牙牙髓血运重建的情况,免疫组织化学染色观察不同时间段各组大鼠再植牙牙体组织中VEGF蛋白表达水平。结果:HE染色,与未拔牙组比较,生理盐水组大鼠再植牙牙髓组织中炎症较重,牙根发育情况较差,修复性牙本质和牙骨质沉积较少,根尖孔较宽;庆大霉素组和EPO组大鼠再植牙牙髓组织中炎症较轻,牙根发育情况相对较好,修复性牙本质和牙骨质沉积较多,根尖孔缩窄。免疫组织化学染色,与未拔牙组比较,3、7和14d时生理盐水组、庆大霉素组和EPO组大鼠再植牙牙体组织中VEGF呈强阳性表达,随着时间的延长,VEGF阳性表达强度逐渐减弱;VEGF阳性表达区的平均吸光度(AOD)值,EPO组>庆大霉素组>生理盐水组>未拔牙组。与未拔牙组比较,3、7、14和21d时生理盐水组、庆大霉素组和EPO组大鼠牙体组织中VEGF蛋白表达水平明显升高(P<0.05),而在28d时各组大鼠牙体组织中VEGF蛋白表达水平差异无统计学意义(P>0.05);与生理盐水组比较,3、7、14和21d时庆大霉素组和EPO组大鼠牙体组织中VEGF蛋白表达水平明显升高(P<0.05),而在28d时庆大霉素组和EPO组大鼠牙体组织中VEGF蛋白表达水平差异无统计学意义(P>0.05);与庆大霉素组比较,各时间点EPO组大鼠牙体组织中VEGF蛋白表达水平差异均无统计学意义(P>0.05)。结论:EPO通过上调VEGF表达,诱导牙髓组织中血管新生,为再植牙提供了丰富的血管床,从而发挥牙髓的防御修复潜能,促进了再植牙的牙髓愈合。

Objective:To investigate the expression of vascular endothelial cell growth factor(VEGF)in the immediate replantation of pulp healing in the rats,and to clarify the effect and its mechanism of erythropoietin(EPO)on immediate pulp reconstruction in the rats.Methods:Eighty 4-week-old healthy male Wistar rats were randomly divided into non-tooth extraction group,negative control(normal saline)group,positive control(gentamicin)group and EPO group;there were twenty rats in each group.The teeth in each group were immersed in its corresponding solution for 4 min before replantation.Four rats were killed on the days 3,7,14,21 and 28,respectively,and the specimens were made in the operation area.HE staining was used to observe the pulp revascularization in different time periods.Immunohistochemical staining was used to observe the protein expression levels of VEGF in odontal tissue of the rats in each group in different time periods.Results:The HE staining results showed that compared with non-tooth extraction group,the pulp tissue of replanted teeth of the rats in normal saline group had more inflammation,less root development,less restorative dentin and cementum deposition,and wider apical pores;the inflammation of pulp tissue of replanted teeth of the rats in gentamicin group and EPO group was mild,and the root development was relatively good;there were more deposits of restorative dentin and cementum,and the apical pores were narrowed.The immunohistochemical results showed that compared with non-tooth extraction group,the positive expressions of VEGF in odontal tissue of the rats at the days 3,7 and 14 in the other groups were strong.Afterwards,the positive expression levels of VEGF were decreased gradually with the prolongation of time.The average optical density(AOD)of VEGF positive area indicated that EPO group >gentamycin group > normal saline group > non-tooth extraction group.Compared with non-tooth extraction group,the protein expression levels of VEGF in odontal tissue of the rats in normal saline group,gentamicin group and EPO group at 3,7,14 and 21 dafter operation were significanty increased(P<0.05),but the protein expression levels of VEGF in odontal tissue of the rats at 28 dhad no significant differences(P>0.05).Compared with normal saline group,the protein expression levels of VEGF in odontal tissue of the rats in gentamicin group and EPO group at 3,7,14 and 21 dafter operation were significantly increased(P<0.05),but the protein expression levels of VEGF in odontal tissue of the rats at 28 dhad no significant differences(P>0.05).Compared with gentamicin group,the protein expression levels of VEGF in odontal tissue of the rats in EPO group at every time points had no significant differences(P>0.05).Conclusion:EPO can increase the expression of VEGF,induce angiogenesis in pulp tissue,and provide the rich vascular bed for replantated teeth,so as to exert the potential of dental pulp defense and repair,and promote the healing of replanted teeth.