| Objective:After the establishment of non-vital root canal model in mandibular first molar,SD rats were delivered AMD3100 in different methods and the SDF-1 polypeptide hydrogel scaffold was implanted 1 hour after delivery.To observe the effect of AMD3100 on the pulp regeneration induced by SDF-1 and the different effects of AMD3100 delivery.Methods:1.18 female SD rats(SPF-grade)aged from six to eight weeks with a body weight of 180-220g(198.2±9.9g)were randomly selected for one side of the mandibular first molars of SD rats as experimental teeth to establish a non-vital root canal model.2.1 week after the establishment of non-vital root canal model.The rats were randomly divided into control group,the AMD3100 subcutaneous injection group and AMD3100 vestibular groove injection group with six SD rats in each group.The control group rats were subcutaneous injected saline,the AMD3100 subcutaneous injection group rats were subcutaneous injected with AMD3100(5mg/kg),and the AMD3100 vestibular groove injection group rats were injected with AMD3100(5mg/kg)in the buccal vestibular groove of the experimental teeth.3.1 hour after injection,all experimental teeth were implanted with50ng/mL SDF-1 polypeptide hydrogel scaffold.4.All animals were sacrificed in 14 days after implantation.HE,Masson and CD34 immunohistochemical staining were performed to observe the tissue regeneration in the root canal and to compare the differences among the groups.Results:27 samples were collected in this experiment,consisting of 9samples for each group.HE staining observation shown that,in the control group(n=9/9)and the AMD3100 subcutaneous injection group(n=9/9),new tissue formation was observed in all root canals of the samples,while in the AMD3100 vestibular groove injection group,new tissue formation was observed only in part of the root canals of the samples(n=6/9).The new tissue was dominated by fibroblast-like cells growing into the root canal through the apical foremen.Vessel structures could be seen in some new tissues of the samples.Fewer vessel structures were found in the new tissues in the control group(1/9)at the apical third of the root canal,while more new vessel structures were found in the AMD3100 subcutaneous injection group(n=6/9)and the AMD3100 vestibular groove injection group(n=3/9).In the AMD3100 subcutaneous injection group,the distribution of vessel structures could be seen in the whole length range of the new tissue from the apical third to middle third of root canal in some samples,while in the AMD3100 vestibular groove injection group,the distribution was only at apical third of the root canal.Masson staining observation shown that,in the control group,there were dense,disordered blue staining collagenous fibers with less vessel-like structure inside(1/9).In the AMD3100 subcutaneous injection group,the blue staining collagenous fibers were ordered and loose with abundant vessel-like structure from the apical third to middle third of the root canal(6/9).In the AMD3100 vestibular groove injection group,there were blue staining collagenous fibers which were disordered and dense,the blue staining collagenous fibers were not only disordered and dense,the vessel-like structures were in the apical third of root canal in some samples(3/9).The statistical analysis of area ratio of new tissue in coot canal shown that,there were statistically significant differences among three groups(p<0.05).When compared between two groups,the area ratio of new tissue in root canal in the AMD3100 vestibular groove injection group was lower than in the control group and the AMD3100 subcutaneously injection group,the differences were statistically significant(p<0.05).The difference was not statistically significant between the control group and the AMD3100 subcutaneously injection group(p>0.05).Immunohistochemical staining observation shown that,there were statistically significant differences among three groups(p<0.05).When compared between two groups,the CD34 positive-microvessel number of new tissue in root canal in the AMD3100 subcutaneously injection group was higher than in the control group,the difference was statistically significant(p<0.05).And the difference was not statistically significant between other groups(P>0.05).Conclusion:1.The non-vital root canal model was successfully established.2.The amount of new tissue in the root canal,the length of coronal extension and vessel structures were limited only by implanting 50ng/mL SDF-1polypeptide hydrogel scaffold in the root canal.3.The subcutaneous injection of AMD3100 could promote the formation of new blood vessels in the new tissue induced by the implantation of SDF-1polypeptide hydrogel scaffold in root canal.4.The difference of the AMD3100 injection sites had a certain impact on the formation of new tissues induced by SDF-1 polypeptide hydrogel scaffold,the subcutaneous injection method could better exert the promotion effect of AMD3100 for the formation of new tissue in root canal,and the effect of vestibular groove injection method was not obvious. |
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