miRNA‐200b improves hepatic fibrosis induced by CCL4 by regulating toll‐like receptor 4 in mice

Abstract

To study the effect of miRNA‐200b on hepatic fibrosis induced by CCl4 in mice. The C59BL/6 mice were randomly divided into three groups (normal control [NC], CCLR model [Model], and CCl 4\u2009+\u2009miRNA‐200b [miRNA]). The hepatic fibrosis was induced by CCl 4 injected subcutaneously twice per week in Model and miRNA groups. After 6 weeks building model, the mice of miRNA group were injected the miRNA‐200b from caudal vein twice per week. The mice of Model and miRNA groups were continuously fed for 3 weeks. The IL‐1β, IL‐6, and TNF‐α concentrations of serum were measured by enzyme‐linked immunosorbent assay. The hepatic tissues of difference groups were observed by hematoxylin and eosin (H&E) staining, sirius red staining, Masson staining, and terminal deoxynucleotidyl transferase dUTP nick end labeling assay and measured toll‐like receptor 4 (TLR4) and nuclear factor‐κB (NF‐κB) proteins expressions by western blot assay. The correlation between miRNA‐200b and TLR4 were analyzed by dual luciferase target assay. Compared with NC group, the interleukin‐1β (IL‐1β), IL‐6, and tumor necrosis factor‐α (TNF‐α) concentrations of Model group were significantly upregulated (P\u2009<\u20090.05, respectively). With miRNA‐200b overexpression, the IL‐1β, IL‐6, and TNF‐α concentrations were significantly suppressed (P\u2009<\u20090.05, respectively). The pathologies were improved by H&E staining, sirius red staining, and Masson staining; meanwhile, the hepatic cell apoptosis rate was significantly suppressed (P\u2009<\u20090.05). The TLR4 and NF‐κB protein expressions of miRNA group were significantly suppressed compared with the Model group (P\u2009<\u20090.05, respectively). By dual luciferase target assay, the TLR4 was a target gene of miRNA‐200b. The miRNA‐200b upregulation improved hepatic fibrosis induced by CCl 4 via regulation of TLR4 in vivo.