The Biological Role Of Tgfb1 In The Development Of Enamel And The Research Of Its Molecules Mechanism

Objective:TGF-?1 is a member of the transforming growth factor-P super family,has extensive biological functions in vivo and in vitro,but the specific function of TGF-?1 in the development of tooth enamel is not clear.The purpose of this study is through building Tgfbl ameloblasts conditional knockout mice model to further explore the molecular mechanism of TGF-?1 in the development of tooth enamel.Method:(1)IHC analysis the anti-TGF betal expression to confirm the successful knockout of Tgfbl in the wild-type mice(C57BL/6).(2)qRT-PCR further verify that the expression of Tgfbl gene in Tgfbl knockout mice was significantly reduced.(3)Analysis the teeth appearance by Macroscopic and SEM.(4)Micro-CT analyses the density of enamel difference between wild-type mice and Tgfb1cKO mice.(5)Histological Analysis the difference between wild-type mice and Tgfb1cKO mice through HE.(6)SEM structure of enamel in Tgfbl null mice and wild-type mice.(7)Real-time PCR analyses the expression of the enamel relative gene.Results:Immunohistochemical results found that the negative expression of the anti-TGF betal in the ameloblast cytoplasm of PN7 null mice.The mRNA expression of Tgfbl in knockout mice significantly lower than that in wild type mice,suggested that Tgfb1conditional knockout in meloblats successfully.Microscope and Scanning Electron Microscopy(SEM)showed that 1 months after birth Tgfbl knockout mice bad tooth enamel mineralization,micro CT showed the desity of PN21 Tgfb1 knockout mice enamel significantly decreased,but the scanning electron microscope showed the PN14(before the eruption)Tgfbl knockout mice teeth size and shape had no obvious difference was found compared with the wild type mice,demonstrated that Tgfbl main influencing enamel mineralization in the late,but had no obvious effect on early enamel development.Both the Scanning electron microscope and HE could find the residues of enamel matrix in the early-maturation Tgfbl cKO enamel and real-time PCR showed that the expression of the enamel protein and protease in the early-maturation Tgfbl knockout ameloblasts was significantly changed,suggesting that Tgfbl plays a major role in the transition and early maturation stage.Conclusion:Tgfb1~loxp/loxp,K14-Cre+,in early epithelial cells specificity conditional knockout Tgfb1,cause poor enamel mineralization,suggesting that Tgfb1 plays an important role in mineralization during enamel development.Further study showed Tgfbl mainly affect the enamel mineralization by regulating the enamel-related protein and protease.