| Letinous edodes is a common edible fungus in our daily life.The production of letinous edodes in China is the largest in the world,and letinous edodes is known as the "king of mushrooms",with a variety of physiological functions.At the same time,there are a few researches about beta-glucan as an important pharmacological active substance in letinous edodes.The molecular mechanism of its anti-inflammatory effect is still not clear.This thesis mainly focuses on ?-glucan which is extracted from letinous edodes(?Gs)for the prevention and amelioration of inflammatory colitis.In the study,lipopolysaccharide(lipopolysaccharide,LPS)induced macrophage RAW264.7 cell inflammation model and dextran sulfate sodium(sodium dextran,sulfate,DSS)induced inflammatory colon of mice(inflammatory bowel disease,IBD)inflammation model be used to evaluate letinous edodes beta dextran anti-inflammatory effect and explore its molecular mechanism involved.To research the anti-inflammatory physiological function of letinous edodes beta glucan from the molecular level,which provides a significat theoretical basis for the more effective utilization of letinous edodes resources in the future?In the ?Gs-treated groups,the mental status of the mice was improved,a small amount or no blood in the stool was visible,and the DAI score was significantly reduced.Compared with the DSS-treated group,?Gs significantly ameliorated of colonic ulcer,edema,bowel wall thickening,and shorter length.Tissue sections were observed under a microscope.Compared with the normal group,the colon tissues of mice in the DSS-treated group showed significant acute inflammatory reaction symptoms such as mucosal erosion,ulcers,destroying of gland crypt structure,neutrophil infiltration and loss of goblet cells.In the PGs protective group mice,the above symptoms were obviously improved.The levels of MPO,MDA and NO content in DSS-treated/control groups were 2.37,3.06 and 2.62,respectively.Compared with the control group,the levels of MPO,MDA and NO in low PGs-treated group were 1.96,2.18 and 1.96,respectively.And the levels of MPO,MDA and NO in high PGs-treated group were 1.56,2.00 and 1.79,respectively.The results indicated that the content of MPO,MDA and NO in the colon tissues were significantly decreased in the ?Gs-treated group.Compared with the control group,the mRNA expressions of four inflammatory factors in the colon tissue of the DSS-treated group were increased by 5.58,4.12,4.09 and 9.73 times,respectively.Compared with the control group,the mRNA levels were 3.44,3.13,2.73 and 5.85 fold in low-pGs-treated group,the the mRNA levels were 2.33,2.13,2.19 and 4.53 fold in high-?Gs-treated group,respectively.PGs-treated mice can significantly reduce the expressions of these inflammatory cytokine mRNAs in the colonic tissues.The expression levels of TNF-?,IL-1?,IL-6 and iNOS in the colon tissues of the DSS-treated group were 1.55?2.23?1.54 ? 2.0 times higher than that of the control group,respectively.While the four proteins in the low-?Gs-treated group were 1.48?2.14?1.51 and 1.50 times,in the high-?Gs-treated group were 1.24?1.49?1.26 and 1.55 times,respectively.?Gs significantly down-regulated the expression of the above-mentioned inflammatory factor protein in mouse colon tissues.Compared with the control group,the mRNA expression levels of TNF-?,IL-1?,IL-6 and iNOS in the LPS-induced group increased by 4.19,4.88,6.72 and 4.77 times.Compared with the LPS-induced group,100 pg/m L,200 ?g/mL and 400 ?g/mL three groups of ?Gs-protected cells were significantly decreased in a dose-dependent manner.?Gs significantly reduced LPS-induced over expression of the above-mentioned inflammatory factors mRNA in RAW264.7 cells.The expression of TNF-?,IL-1?,IL-6 and iNOS in the LPS-induced cells were 2.27,2.09,1.88 and 1.93 times higher than those in the control group.Compared with LPS-induced cells,the expression levels of four proteins in the ?Gs-protected group was significantly lower than that in LPS-induced group,and the difference was significant and dose-dependent.PGs can significantly reduce the expression levels of inflammatory protein in the total protein.Effects of c on LPS-induced transcriptional activity of PPARy and Elk-1 in RAW264.7 cells:Compared with the control group,the expression levels of PPARy and Elk-1 phosphorylated protein in LPS-induced group increased by 1.27 and 1.76 times,respectively.Compared with control group cells,the expression of PPARy and Elk-1 phosphorylated protein in the cells of Gs-treated group was significantly decreased in a dose-dependent manner.?Gs significantly increased the nuclear translocation of PPARy and inhibited the transcription of Elk-1 in inflammatory cells.Phosphatidylation of key target molecules in MAPK pathway in RAW264.7 cells by ?Gs:Compared with control group cells,the phosphorylation of p38 and JNK in the cells of ?Gs group was significantly decreased in a dose-dependent manner.The expression of p-ERK1/2 in 400 ?g/mL ?Gs-treated group was significantly decreased.These results suggested that ?Gs could inhibit the level of phosphorylation in a dose-dependent manner.Effect of ?Gs and MAPK inhibitors on expressions of the transcriptional activity of PPARy and Elk-1 in RAW264.7 cells induced by LPS were evaluated by using western blotting.The results revealed the significantly decreased expression levels of phosphorylated protein of PPAR? and Elk-1 in the MAPK inhibitors+?Gs groups,which indicating that MAPK phosphorylation can inhibite the the nuclear translocation of PPARy and increase the transcription of Elk-1.?PGs show the anti-inflammatory effects by inhibiting MAPK pathway.Comprehensive analysis,in the whole animal model,PGs could significantly improve the health status of DSS-induced colitis in mice,reduce the DAI score and improve the damage of pathological tissue and decrease the activity of MPO and MDA and NO in colon;the expression of TNF-?,IL-1?,IL-6 and iNOS were down-regulated in colonic tissues;increasing the transcriptional activity of PPARy and inhibiting the transcriptional activity of Elk-1 in colon.In the cellular model,?Gs could down-regulate the expressions of TNF-?,IL-?,IL-6,and iNOS genes,promoting the transcriptional activity of PPARy and inhibiting the transcription of Elk-1,decrease the phosphorylation of p38,JNK and ERK1/2 in RAW264.7 cells which induced by LPS.In addition,MAPK inhibitors significantly increased PPAR-?and inhibited Elk-1 transcriptional activity in the presence of ?Gs. |
PDF Full Text Request