Viili Exopolysaccharides On The Activation Of Macrophages RAW264.7 Cells And The Associated Cytokines

Viili has been traditionally regarded as healthy food; viili exopolysaccharides (VEPS) as immunological booster, but its molecular mechanisms remain unclear. VEPS was obtained by protein precipitation of isoelectric point, Sevage’s method, enzyme hydrolysis method. The yield of crude polysaccharide was 55 mg/mL. Crude VEPS was further purified by anion exchange chromatography, and VEPS-1, VEPS-2 and VEPS-3 were collected, then mixed them to be VEPS, the total sugar content of VEPS was 80%.For structure, the VEPS was studied by GC and LC analysis, which showed that the VEPS contain the sugar units joined by (1 �' 4) glycosidic bonds. It was mainly contained rhamnose, glucose and galactose. The contents ratio was 8.32%,46.17%,40.09%.To study the cell activation of RAW264.7 under influences of viili exopolysaccharides (VEPS).VEPS was tested in LPS-stimulated and non-stimulated RAW264.7 macrophages. Cell proliferation was analyzed by MTT with different concentration of VEPS, phagocytosis was detected by neutral red; The secretion of NO and IL-6、IL-1β in the supernatant of cell culture was measured with Griess kit and the elisa kit, respectively, cell morphology was observed by scanning electronic microscopy (SEM), and cell cycles by flow cytometry. The results indicate that the cell proliferation, the uptake of neutral red for indication of phagocytosis, releases of NO and cytokines IL-6 and IL-1β after exposure to LPS and VEPS were increased by VEPS at 50-200 μg/mL, respectively. By using semi-quantitative RT-PCR, gene expression of inducible nitric synthase (iNOS), IL-6, IL-1β was increased with VEPS alone. However, inhitition was observed when same concentrations of VEPS were used at the presence of LPS, that is, VEPS reduced NO、IL-6、 IL-1β secretion that was caused by LPS, which suggests VEPS play a modulation role. By using semi-quantitative RT-PCR, gene expression of inducible nitric synthase (iNOS), IL-6, IL-1β was decreased with VEPS and LPS together. VEPS also increased protein expression of inducible nitric synthase (iNOS). All data show that VEPS promotes immunity by activating macrophages, and VEPS also plays anti-inflammatory roles by regulation of the balance of cytokines.