Objective:To investigate the influences of emodin up-regulation of miR-218 expression on bone mineral density(BMD)and inflammatory response in chronic periodontitis rats.Methods:A rat model of chronic periodontitis was constructed and randomly grouped into model group,emodin low-dose group(20 mg·kg-1),emodin high-dose group(40 mg·kg-1),NC group(miR-218 NC),miR-218 overexpression group(miR-218 agomir),and emodin +miR-218 inhibitor group(emodin40 mg·kg-1 +miR-218 antagonist group),with10 rats per group.Another 10 normal-raised rats were gathered as the normal group.qRT-PCR was used to detect the expression of miR-218 in rat periodontal tissue;Micro-CT scanning was performed to detect the changes of BMD and bone microstructure in rats;hematoxylin-eosin(HE)staining was used to measure the pathological changes of periodontal tissue;ELISA was used to measure the levels of tumor necrosis factor-α(TNF-α),interleukin(IL)-1β,IL-6 in serum;Western Blot was used to measure the expression of MMP-9,COL Ⅰ ,COL Ⅳ and DSP proteins in periodontal tissue.Results:Compared with the normal group,the rats in the model group had inflammatory cell infiltration,deeper periodontal pockets and obvious bone resorption,the number of maxillary trabecular bone(Tb·N),separation distance of trabecular bone(Tb·Sp),the serum levels of TNF-α,IL-1β,IL-6,and the expression of periodontal tissue MMP-9 protein increased significantly(P<0.05);the BMD,bone volume to tissue volume(BV/TV),thickness of trabecular bone(Tb·Th),miR-218 expression and the expressions of COL Ⅰ ,COL Ⅳ and DSP in periodontal tissue decreased significantly(P<0.05).In emodin low,high-dose group,the inflammatory cell infiltration and bone resorption in periodontitis rats were improved,the maxillary Tb·N,Tb·Sp,the serum levels of TNF-α,IL-1β,IL-6,and the expression of MMP-9 protein in periodontal tissue decreased significantly(P<0.05);the BMD,BV/TV,Tb·Th,miR-218 expression and the expression of COL Ⅰ ,COL Ⅳ and DSP proteins in periodontal tissues increased significantly,the influence trend of miR-218 overexpression on periodontitis rats was consistent with that of emodin low-dose and high-dose groups(P<0.05).Compared with the emodin high-dose group,the above indexes were reversed in the emodin +miR-218 inhibition group(P<0.05).Conclusion:Emodin can improve BMD and inflammatory response in rats with chronic periodontitis,and its mechanism may be related to up-regulation of miR-218 expression.
emodinmicroRNA-218chronic periodontitisbone mineral densityinflammatory response