Study On The Effect Of Activin B In The Animal Model Of Pulp Implantation Of Deciduous Teeth

Purpose:The animal model of dental empty canal in nude mice was established.The early microenvironment of deciduous dental pulp after root canal implantation was regulated by activin B,the distribution of blood supply establishment and the formation of dental pulp dentin complex were observed,and the role of activin B in dental pulp revascularization was evaluated.Method:After disinfecting the surface of the retained deciduous teeth extracted clinically,take them out,place them in the culture medium,seal them at low temperature and send them to the laboratory.There were five experimental groups,6 samples per group: deciduous dental pulp group(group A),deciduous dental pulp+matrigel group(group B),deciduous dental pulp+matrigel+activin B group(group C),and the control group was matrigel group(group D)and empty root group(group E).According to the experimental grouping requirements,the dental empty tubes to be implanted were treated and implanted subcutaneously in nude mice.After 8weeks,the nude mice were killed due to cervical dislocation,and the root canal was removed.The distribution of blood supply and the formation of pulp dentin complex in deciduous teeth after root canal implantation were evaluated by HE and immunohistochemistry.Result:1.HE staining results: in group D and group E,a small amount of fibrous connective tissue was found in the root canal,and vascular endothelial cells formed vascular cavities of different numbers and sizes.In group A,fibrous connective tissue and pulp tissue were found in the root canal,and obvious vascular lumen was formed by vascular endothelial cells,most of which were small vascular cavities.In group B,there were more fibrous connective tissue and pulp tissue in the root canal,the number of vascular endothelial cells increased,and some formed a large number of vascular cavities,most of which were new small vascular cavities.In group C,there were more fibrous connective tissue and pulp tissue in the root canal,and a large number of vascular cavities were formed by vascular endothelial cells,most of which were new small vascular cavities,filled with blood,and the neovascular cavities of some samples filled the whole root canal.2.Immunohistochemical results: human CD31 was negative,mouse CD31 was positive and human nestin was negative in group D and group E.In group A,human CD31 was positive and mouse CD31 was negative;in the connective tissue area of rats,mouse CD31 was positive and human CD31 was negative.Human nestin was positive,and the positive cells are distributed in dental pulp tissue,which is similar to the positive expression area of human CD31.In group B,human CD31 was positive and mouse CD31 was negative in the pulp tissue area in the root canal;in the connective tissue area of rats,mouse CD31 was positive and human CD31 was negative.In group C,human CD31 was positive and mouse CD31 was weakly positive.Human nestin was positive in the latter two groups,and the positive cells were widely distributed in dental pulp tissue,which was similar to the positive expression area of human CD31.3.Statistical analysis of microvessel count: there was significant difference in the number of blood vessels in group A,group B and group C.By comparison,it was found that there were differences in angiogenesis between group A and group B,and there were differences in angiogenesis between group A and group C.There was no difference in angiogenesis between group B and group C.4.Statistical analysis of optical density: there was significant difference in the average optical density of group A,group B and group C.By comparison,it was found that there were differences in the average optical density between group A and group B,and there were differences in the average optical density between group A and group C.There was no difference in the average optical density between group B and group C.Conclusion:In the nude mouse model,the connective tissue grew into the root canal and contacted with the pulp of deciduous teeth,and neovascularization was observed in the pulp.This experiment can not explain the effect of activin B on pulp revascularization.