| Background and purpose:Type 2 diabetes mellitus and hyperlipidemia,as very common chronic systemic diseases,both have inhibitory effects on bone regeneration.At the same time,studies have shown a very close relationship between the two diseases:type 2 diabetes is often associated with elevated blood lipids.TAZ-Runx2 signaling pathway is one of the important signaling pathways in the differentiation of osteoblasts,and TAZ can promote the proliferation of osteoblasts by activating Runx2.Therefore,based on the establishment of a model of mandibular bone defect in the high-fat and high-glucose mice,this study investigated the effect of high-fat and high-glucose microenvironment on bone regeneration and further investigated the role of Runx2 and TAZ in this process.Methods:1)On the basis of aopE-/-mice,the model of high-fat and high-glucose mice was successfully established with the modeling method of type 2 diabetes.And high-fat mouse model,high-glucose mouse model and normal group mouse were also established as the control group.At 0 d(preoperative),7 d(postoperative),14 d(postoperative)and 28 d(postoperative),random blood glucose,TC,TG,LDL-C and HDL-C were performed.2)On the basis of the successful establishment of the above mouse model,bone defects of 1 mm × 1.5 mm across the buccal-lingual direction were made at the lower margin of the right mandible in the four groups of mice.3)Four groups of mice were sacrificed at 7 d,14 d and 28 d,respectively.The right mandible tissue of the mice was taken,and the regeneration of the mandible bone defect was evaluated by HE staining,modified-Masson staining,Trap staining and ALP immunohistochemical staining,respectively.4)The expression of Runx2 and TAZ at 7 d,14 d and 28 d during bone regeneration was detected by immunohistochemistry,qRT-PCR and Western Blot.Results:1)The random blood glucose levels of mice in the high-fat and high-glucose group were much higher than 16.9mmol/L at 0 d,7 d,14 d and 28 d,and the TC,TG,LDL-C and HDL-C at four time points were significantly higher than those in the normal group,and the TG and LDL-C level was the most obvious.In the high-fat group,only the blood lipid level was significantly increased,and the blood glucose was kept less than 16.9mmol/L.The blood glucose level of the mice in the high-glucose group was much higher than 16.9mmol/L,but the blood lipid level was not statistically significant compared with that of the normal group.2)HE staining,modified-Masson staining,Trap staining and the IHC of ALP at 7 d,14 d and 28 d all showed that the bone regeneration of mandibular defects in the high-fat group,the high-glucose group and the high-fat and high-glucose group were significantly lower than those in the normal group,and the bone regeneration in the high-fat and high-glucose group was the worst,significantly lower than the other three groups.3)The results of IHC,qRT-PCR and Western Blot of Runx2 and TAZ expression at 7 d,14 d and 28 d showed that the expression of Runx2 in the other three groups was weaker at three time points compared with the normal group,and the high-fat and high-glucose group was the weakest.However,when comparing the expression of TAZ in the four groups at each time point,the results showed that the expression level of TAZ in the high-fat and high-glucose group was significantly lower than that in the normal group at each time point,which was consistent with the expression trend of Runx2.The expression level of TAZ in both high fat group and high glucose group did not show the same results as that of Runx2.Conclusion:Through the establishment of type 2 diabetes in aopE-/-mice,the high-fat and high-glucose mouse model was successfully established,and the bone defect model of the mouse mandible was established on the basis of the model.In addition,the inhibitory effect of high-fat and high-glucose microenvironment on bone regeneration was significantly enhanced compared with the pure high-fat or high-glucose state,and Runx2 and TAZ were involved in this inhibitory effect. |
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