[Molecular mechanism of total flavonoids in Isodon amethystoides on adjuvant arthritis in rats].

Our preliminary study showed that the total flavonoids in Isodon amethystoides(TFIA), a local medicinal herb in Suzhou, had a certain therapeutic effect on adjuvant arthritis, and this therapeutic effect may be achieved through the up-regulation of miR-152 expression. In this paper, the molecular mechanism of TFIA on the pathogenesis of adjuvant arthritis(AA) rats was further studied. AA rats were prepared with complete Freund's adjuvant, and then treated with TFIA by intragastric administration. Real-time qPCR was used to detect the effects of TFIA on the negative regulatory loop of miR-152, methylase DNMT1 and methyl-CpG binding protein MeCP2 in fibroblast like synoviocytes(FLS) of AA rats, as well as the effects of TFIA on the classic Wnt signaling pathway and the expression of fibronectin gene in AA rats. Intragastric administration of TFIA significantly inhibited the expression of DNMT1 and reversed the negative regulatory loop composed of miR-152, DNMT1 and MeCP2 in the pathology of AA rats. After transfection of miR-152 inhibitors into the FLS in treatment group, DNMT1 expression was significantly restored. TFIA significantly up-regulated the expression of SFRP4 and inhibited the expression of β-catenin, C-myc and ccnd1, the key genes of canonical Wnt signaling pathway. TFIA also significantly inhibited the expression of fibronectin, an AA gene. The effect of TFIA on the expression of SFRP4, β-catenin, C-myc, ccnd1 and fibronectin was reversed after transfection with miR-152 inhibitors in the treatment group FLS. TFIA may inhibit the DNMT1 expression, up-regulate the SFRP4 expression, inhibit the expression of classical Wnt signaling genes β-catenin, C-myc, and ccnd1 as well as the RA gene fibronectin expression through the up-regulation of miR-152 expression.