| Objective:Root resorption is one of the most common complications in orthodontic treatment,which defined as the destruction of apical structure caused by pathological loss of dentin and cementum.Orthodontic root resorption related to orthodontics often occurs at the root tip,which may be related to the coverage of one-third of the root tip by cellular cementum.The affected teeth with root resorption may have no obvious clinical manifestations.Only the X-ray film shows irregular insect erosion defects on the surface of the root,which can seriously shorten the root and even lead to the fall off teeth.Cementoblasts can form cementum and play an important role in cementum repair.Therefore,promoting cementum regeneration provides a new idea for orthodontic patients to treat root resorption.Fibroblast growth factor 21（FGF21）is a regulator that regulates glucose and lipid metabolism in an endocrine manner.At present,the researches mostly focus on the important application value of FGF21 in the treatment of diabetes,obesity,hypertriglyceridemia and other diseases,and its role in bone metabolism has not been fully understood.Some studies have shown that FGF21 can inhibit bone formation.Wei et al.found that FGF21 transgenic mice showed low bone mass,while FGF21 knockout mice showed high bone mass.Li et al.found that the osteogenic differentiation of human bone marrow mesenchymal stem cells in high glucose environment was inhibited by FGF21.Therefore,we can speculate that FGF21 plays a role in bone metabolism.Because osteoblasts and cementoblasts have many similar biological characteristics,and the effect of FGF21 on cementoblasts is not clear.Therefore,this study hopes to explore the effect and mechanism of recombinant human FGF21 on the proliferation and mineralization of cementoblasts,so as to provide a new idea for the treatment of root resorption in the process of orthodontics.Methods:Immunohistochemical staining was used to study the expression and distribution of FGF21 in rat periodontal tissue,and immunofluorescence was used to detect the expression of FGF21 in mouse cementoblast cell line OCCM-30.Cell counting kit-8 was used to detect the proliferation of OCCM-30 treated with different concentrations of rhFGF21.Alkaline phosphatase staining and alizarin red staining were used to detect the early and late differentiation phases of OCCM-30.The transcription level and protein expression of osteogenesis related genes Runx2 and Osterix were evaluated by real-time quantitative polymerase chain reaction and western blot,respectively.The expression levels of genes of TGFβ/BMP signaling pathway in cementoblasts added with rhFGF21 were detected by PCR array.Results:FGF21 expressed in periodontal tissue and cementoblasts.The rhFGF21 could not regulate the proliferation of cementoblasts,but promoted the late phase mineralization at concentrations of 25 and 50ng/ml.The expression of Runx2 gene and its protein increased during the OCCM30 differentiation.In addition,rhFGF21 activated intracellular TGFβ/BMP signaling pathway to regulate OCCM-30 mineralization to some extent.The protein expression of bone morphogenetic protein receptor lb,a key downstream mediator of this signaling pathway,was up-regulated after the addition of rhFGF21.Conclusion:The results showed that FGF21 was positively expressed in periodontal tissue.FGF21 could promote the mineralization process of cementoblasts,which may be related to the activation of intracellular TGFβ/BMP signaling pathway. |
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