Expression Of MITF In Induced Mice Periapical Periodontitis And Typical Dental Pulp Diseases Report

Objective:To establish a model of periapical periodontitis in wild-type mice to observ e theexpression of MITF(Microphthalmia-associated Transcription Factor)in ex perimental periapical lesions in mice.Methods:Twenty-five C57 BL / 6J mice,aged 6-8 weeks and weighing 20-22 g.The mouse model of periapical periodontitis was established by exposing the medul lary canal to the oral cavity after the first mandibular first molars were opened in mice.After exposure,five mice were randomly sacrificed at each time point of 0,1,2,3 and 4 weeks,and the time point of 0 week were used as blank control.Then carried out heart perfusion with paraformaldehyde,then extracted lower jaws,made frozen sections.The pathological changes of periapicalinflam mation wereconfirmed byhematoxylin-eosin(HE)staining.MITF polyclonalantibod y was used for immunohistochemical staining to detect the expressionand distrib ution.Correlation between the expression of osteoclasts and theexpression of MI TF in osteoclasts around periapical tissue by enzymatic histochemical staining.Results:1.hematoxylin-eosin(HE)stainThe results of HE staining showed that in the group of 1 week,a small a mount of neutrophil infiltration was observed in the periapical area of the mand ibular first mo-lar.In the group of 2 week,the mandibular first molar had co mplete necrosis of the pulp and a large amount of neutrophil and lymphocyte i nfiltration in the Periapicaltiss-ue.In the group of 3 week,inflammatory infiltration range increased,lymphocytes increased and alveolar bone became damaged.I n the group of 4 week,lymphocytes continued to increase,and Howship’slacuna was found near the Periapical tissue.In the group of blank control,mandibular first molar alveolar bone was not damaged,no inflammatory cell infiltration.So the results of HE staining confirmed that the mice periapical periodontitis model was established successfully.2.immunohistochemistry stainIn the blank control group,a small amount of MITF was expressed in peri apical tissues.In the group of 1week,there were a few MITF positive cells in the Periapical tissue of the mandibular first molar.MITF positive cells increased gradually from the 2week to the 4week and reached the peak at the 4week gr oup.The experimental group at each time point the number of positive expressi on were higher than the controlgro-up,the results were statistically significant(P <0.05).3.enzyme histochemical stainingThe blank control group of periapical tissue can be seen in individual TRA P sta-ining positive cells.the group of 1week,a small amount of TRAP-positive cells were found in the periapical tissues of mandibular first molars.the group of 2weeks,the nu-mber of TRAP-positive cells increased.At the group of3 wee ks,the number of TRAP-positive cells reached the peak.The group of 4weeks,t he number of TRAP-stained cells decreased significantly,with a statistically sign ificant difference(P <0.05).There was a moderate correlation between MITF pos itive staining OD values and TRAP positive cell counts(r = 0.690,P <0.01).Conclusion:MITF in mice periapical inflammatory process with the inflammatory process of expression increased,suggesting that MITF may play a role in the progress of apical periodontal inflammation and bone destruction in mice.But its specific function in periapical bone destruction and inflammatory reactions remains needs further study.