ABSTRACT
To investigate the mechanism by which Schisandra Chinensis mediates the phenotypic transformation of microglia via microRNA-124 (miR-124)-based regulation of the Toll-like receptor 4 (TLR4) pathway, a model was established using lipopolysaccharide (LPS) stimulation of BV2 cells. Cells were treated with different doses of Schisandra Chinensis extract (SCE). MiR-124 inhibitors and negative control sequences (NC inhibitor) were transfected into LPS-induced BV2 cells and treated with SCE. The MTT assay was used for cell activity detection; an NO kit was used to measure NO release; ELISA kits were used to measure the levels of interleukin-10 (IL-10) and tumor necrosis factor-α (TNF-α). Microglia markers, including ionized calcium binding adapter molecule-1 (IBA-1) and arginase-1 (Arg-1), and the nuclear translocation of nuclear factor-kappa B (NF-κB) were evaluated by immunofluorescent staining. NF-κB p65, IBA-1, Arg-1, TLR4, myeloid differentiation primary factor 88 (MyD88), inhibitor of nuclear factor-kappa B kinases-α (IKK-α), IL-10, TNF-α were detected by immunoblot. SCE at concentrations ranging from 31.25 to 250 μg·mL-1 had no significant effect on cell activity. SCE treatment significantly inhibited NO release induced by LPS (P < 0.001, P < 0.01), increased the level of IL-10 (P < 0.05), and decreased the level of TNF-α (P < 0.001). In addition, SCE significantly reduced the expression of TNF-α, IBA-1, TLR4, and MyD88 (P < 0.01, P < 0.001) and elevated the expression of IL-10, Arg-1, NF-κB P65 and IKK-α (P < 0.001, P < 0.01, P < 0.05). SCE treatment could also promote the expression of miR-124 (P < 0.01). However, transfection with the miR-124 inhibitor increased TNF-α (P < 0.001), decreased the level of IL-10 (P < 0.05), increased the mRNA level and the protein expression of TNF-α and IBA-1 (P < 0.05, P < 0.01, P < 0.001), and decreased the mRNA level and protein expression of IL-10 and Arg-1 (P < 0.001, P < 0.01). In addition, the inhibition of TLR4 and MyD88 was attenuated. In conclusion, SCE appears to inhibit the activation of TLR4 signaling pathway by upregulating miR-124 so as to inhibit microglia M1 polarization and promote microglia M2 polarization.
ABSTRACT
The three-step dissolution experiment was established to investigate the in vitro release of budesonide colon-specific tablet and to elucidate the drug release mechanism by fitting to different mathematical models. The physiological parameters of stomach, small intestine and colon such as pH value, intestinal flora, specific organic enzyme, vermiculation and conveying time were mimicked to plot the in vitro dissolution, separately. Sample were taken at predetermined time intervals in 24 h and the accumulated drug releases were determined by using HPLC method. Drug release curves of the localization tablets were fitted to various mathematical models. It shows that no drug release was found in 2 h. About 5% release was determined after 6 h while 77.5% accumulated release was reached within 24 h. Drug release from the in house formulation fitted well into first-order model. The three-step dissolution method could be used to evaluate the colon-specific characteristics of budesonide colonic localization tablet. The drug release behavior of the localization tablet conforms to the drug release mechanisms of controlled porosity osmotic pump where osmotic pressure is the main driving force for controlled delivery of drugs.