金钗石斛多糖对非酒精性脂肪肝病大鼠TLR4和HO-1表达的影响

Influence of Dendrobium Nobile Polysaccharide on the Expression of TLR4 and HO-1 in Rats with Nonalcoholic Fatty Liver Disease

目的:从Toll样受体4(Toll-like receptors-4,TLR4)和血红素加氧酶1(heme oxygenase-1,HO-1)途径研究金钗石斛多糖对非酒精性脂肪肝病(non-alcoholic fatty liver disease,NAFLD)的作用及其分子机制。方法:将清洁级雄性SD大鼠72只,按照随机数字表法分为正常组,模型组,多烯磷脂酰胆碱组,金钗石斛多糖高、中、低剂量组。除正常组外,其余各组建立NAFLD动物模型,给予对应药物灌胃。给药4周后处死,收集血清和肝脏,检测血清天门冬氨酸氨基转移酶(aspartate aminotransferase,AST)、丙氨酸氨基转移酶(alanine aminotransferase,ALT)、血清白细胞介素6(interleukin-6,IL-6)、肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)水平;HE染色观察大鼠肝组织病理学;检测肝脏组织TLR4和HO-1蛋白及mRNA的表达水平。结果:与正常组比较,模型组血清ALT、AST、IL-6、TNF-α明显升高(P<0.05),与模型组比较,多烯磷脂酰胆碱组和金钗石斛多糖组明显降低(P<0.05),此外金钗石斛多糖中、高剂量组IL-6和TNF-α明显低于多烯磷脂酰胆碱组(P<0.05)。正常组肝脏切片可见肝细胞大小均一,细胞核分布均匀,没有脂肪颗粒浸润,模型组则出现明显脂肪颗粒浸润,同时有一定炎症反应,与模型组比较,多烯磷脂酰胆碱组和金钗石斛多糖组明显改善。与正常组比较,模型组TLR4、HO-1蛋白和mRNA表达明显升高(P<0.05),与模型组比较,多烯磷脂酰胆碱组和金钗石斛多糖组明显降低(P<0.05),此外金钗石斛多糖中、高剂量组明显低于多烯磷脂酰胆碱组(P<0.05)。结论:金钗石斛多糖可改善NAFLD大鼠肝细胞炎症反应,改善肝功能,调控肝脏TLR4和HO-1表达。

Objective: To study the effects of dendrobium nobile polysaccharide on NAFLD and its molecular mechanism via TLR4 and HO-1 pathways. Methods: All 72 male SD rats were allocated to the normal group, the model group, Polyene phosphatidylcholine group, high, moderate and low doses groups of dendrobium nobile polysaccharide according to random number table method. Except the normal group, rat models with NAFLD were established in other groups, and drenched with the corresponding herbs. The rats were sacrificed after medicating for four weeks to collect the serum and liver, to detect the levels of AST, ALT, IL-6 and TNF-α;HE staining was used to observe liver histopathology;to detect the levels of TLR4 and HO-1 protein and mRNA in liver tissue. Results: Compared with the normal group, the levels of ALT, AST, IL-6 and TNF-α increased in the model group notably(P<0.05), compared with the model group, polyene phosphatidylcholine group and dendrobium nobile polysaccharide groups decreased remarkably(P<0.05), in addition, the expressions of IL-6 and TNF-α of moderate and high doses groups of dendrobium nobile polysaccharide were lower than these of polyene phosphatidylcholine group(P<0.05). In the normal group, the size of hepatocytes was uniform, the distribution of nuclei was uniform, and no infiltration of fat particles, while in the model group, there was obvious infiltration of fat particles with certain inflammatory reaction, compared with the model group, the improvements of polyene phosphatidylcholine group and dendrobium nobile polysaccharide groups were notable. Compared with the normal group, the expressions of TLR4, HO-1 protein and mRNA increased remarkably in the model group(P<0.05),compared with the model group, the expressions in polyene phosphatidylcholine group and dendrobium nobile polysaccharide groups lowered obviously(P<0.05), In addition, moderate and high doses groups of dendrobium nobile polysaccharide were lower than polyene phosphatidylcholine group(P<0.05). Conclusion: Dendrobium nobile polysaccharide could improve inflammatory reaction of liver cells in NAFLD rats and liver function,regulate the expressions of TLR4 and HO-1 in liver.