| Objective:To explore the dynamic changes of the expression of the characteristic nuclear transcription factors(ROR?t?Foxp3)and related cytokines(IL-17?IL-10?TGF-?1)of immune cells—Help T cell 17(Th17 cell)and T regulatory cell(Treg cell)in the pressure side of the periodontal tissue of rats under different orthodontic force,and their effects on the expression of OPG and the quantity of OC,and to preliminarily investigate the role and relationship of Th17/Treg cell in the reconstruction of periodontal tissue.Methods:A total of One hundred and and forty-four male Wistar rats aged 8-10 weeks with220g±10g were chosen and randomly divided into four groups,including 0g,50 g,100g experimental groups and blank control group,thirty-six rats in each group.Niti tension springs were fixed with ligation wire on the bilateral maxillary first molars to construct the orthodontic reinforcement model.Six rats in each group were executed respectively at the 0th?1th?3th?5th?7th and 14 th day.The first molar and its periodontal tissue was collected.The expression of ROR?t mRNA and Foxp3 mRNA was quantified by realtime quantitative PCR;The expression of IL-17?IL-10 and TGF-?1 protein was quantified by Enzyme-linked immunosorbent assay;The expression of ROR?t?Foxp3 and OPG protein was quantified and the quantity of OC was counted by Immunohistochemistry.Results:1.The expression of Th17 cell related factors(ROR?t and IL-17)increased firstly and then decreased in 50 g and 100 g groups.The peak values of the two groups were on the5 th and 7th day respectively.The expression in 50 g group basically recovered to normal level on the 14 th day,while the 100 g group was still at a high level.Their expression in50 g group were higher than 0g group and lower than 100 g group.2.The expression of Treg cell related factors(Foxp3 ? IL-10 and TGF-?1)also increased firstly and then decreased in 50 g and 100 g groups.The peak values of the two groups were on the 5th and 7th day respectively.Except for the expression of TGF-? 1 in50 g group were higher than 0g group and lower than 100 g group on the 7th day,the rest of the expression in 100 g group were higher than 0g group and lower than 50 g group on the 1th-7th day,the expression of TGF-? 1 in 50 g group were higher than 0g group and lower than 100 g group on the 14 th day.3.The expression of OPG in 50 g group decreased first and then increased,and finally decreased.The lowest value and the highest value were on the 3th and 7th day respectively.It basically recovered to normal level on the 14 th day.The expression of OPG in 100 g group decreased first and then increased.The lowest value and the highest value were on the 5th and 14 th day respectively.4.The change trend and the comparison of OC number was basically consistent with that of Th17 cell related factors.Conclusion:1.This research discovered that expression of characteristic nuclear transcription factors ROR?t and Foxp3 of Th17/Treg cell in the pressure side of periodontal tissue,which confirmed that Th17/Treg cell participated in the process of orthodontic tooth movement.2.Different orthodontic force could have different effects on reconstruction of periodontal tissue on the pressure side after applying orthodontic force by regulating the expression of Th17/Treg cell related factors(ROR?t?IL-17,Foxp3?IL-10?TGF-?1).3.Appropriate orthodontic force(50g)promoted the expression of characteristic nuclear transcription factor ROR?t and the secretion of cytokine IL-17 of Th17 cell,and participated in the bone absorption in the pressure side of periodontal tissue.While Treg cell participated in bone remodeling by expressing its characteristic nuclear transcription factor Foxp3 and cytokine IL-10 and TGF-?1 in the pressure side.4.Excessive orthodontic force(100g)could upset the balance of Th17/Treg cell,make the proliferation of Th17 cell dominant,inhibit the proliferation of Treg cells,which affected bone homeostasis and caused severe damage to periodontal tissue. |
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