RESUMO
PURPOSE: To investigate the mechanism of microRNA-100-5p (miR-100-5p) on mammalian target (mTOR) of rapamycin in temporomandibular arthritis. METHODS: Sixty SD rats were randomly divided into group A, group B, group C, group D, and group E, with 12 rats in each group. Rat models of temporomandibular arthritis were prepared by injecting sodium iodoacetate solution into the bilateral spaces of temporomandibular joint. After establishment, group C was injected pcDNA3.1-miR-100-5p recombinant plasmid, group D was injected mTOR inhibitor rapamycin, group E was injected with pcDNA3.1-miR-100-5p recombinant plasmid and rapamycin, and group A was injected same amount of normal saline in the same way. Various indexes were observed in each group, including morphological changes of temporomandibular joint tissues, matrix metalloproteinase-3 (MMP-3), MMP-1, MMP-13, interleukin-1ß (IL-1ß), tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), miR-100-5p, mTOR expression. The data were processed using SPSS 22.0 software package. RESULTS: In group B, the structure of temporomandibular joint was fuzzy, with synovial hyperplasia, vascular dilatation, clustered cells and a large amount of inflammatory infiltration. Histopathological changes of temporomandibular joint in each interventional group were improved to different degrees compared with group B, among which group E showed the most obvious improvement. The levels of MMP-3, MMP-1, MMP-13, IL-6, IL-1ß and TNF-α in group B were significantly higher than those in group A(Pï¼0.05). The levels of MMP-3, MMP-1, MMP-13, IL-6, IL-1ß and TNF-α in group C, group D and group E were significantly lower than those in group B(Pï¼0.05). The levels of MMP-3, MMP-1, MMP-13, IL-6, IL-1ß and TNF-α in group D were not significantly different from those in group C (Pï¼0.05). The levels of MMP-3, MMP-1, MMP-13, IL-6, IL-1ß and TNF-α in group E were significantly lower than those in group D (Pï¼0.05). The expression level of miR-100-5p in group E was significantly higher than that in group B (Pï¼0.05). The expression level of mTOR protein in group E was significantly lower than that in group B (Pï¼0.05). CONCLUSIONS: MicroRNA-100-5p may alleviate temporomandibular arthritis by down-regulating the expression of mTOR.
