天麻多糖对高脂饮食诱导的非酒精性脂肪肝的保护作用

目的:探讨天麻多糖对非酒精性脂肪肝的保护和延缓作用及其相关分子机制。方法:将60只ICR小鼠随机分成正常组、模型组、天麻多糖给药组(50、100和200 mg/kg)，除正常组给予普通饲料外，其余各组给予高脂饲料以诱导模型。同时，按剂量给予相应的药物，每 d 1次，持续10周。末次给药后30 min，记录小鼠体重及脏器指数，通过组织病理学方法评估肝脏组织的病理变化，分别测定小鼠血清天冬氨酸氨基转移酶（Aspartate amino transferase，AST）、丙氨酸氨基转移酶（Alanine amino transferase，ALT）活力，并同时检查与氧化应激损伤和脂质代谢相关的信号转导途径。结果:与模型组相比，天麻多糖可显著降低血清中AST和ALT活性（P<0.05），减轻脂肪肝组织病理损伤症状，同时调节多种与脂质积累相关的基因表达水平改善脂质代谢（P< 0.05）；此外，天麻多糖还通过上调Nrf2/GPx信号途径改善氧化应激损伤（P<0.05），抑制肝组织中NF-κB、TNF-α、IL-1β以及与炎症反应相关的iNOS和COX-2蛋白表达（P<0.05），并同时可抑制Bax表达，上调Bcl-2因子（P<0.05）。结论:天麻多糖可以改善小鼠的肝功能，调节脂质代谢水平减少脂肪堆积，同时缓解肝脏氧化应激损伤和抑制炎症来保护和延缓高脂饮食引起的非酒精性脂肪肝症状。

Protective Effect of Polysaccharide from Gastrodia elata Blume on Non-alcoholic Fatty Liver Induced by High Fat Diet

Objective: To investigate the protective and delayed effects of Gastrodia elata polysaccharide on non-alcoholic fatty liver (NAFLD) and its molecular mechanism. Methods:60 ICR mice were randomly divided into normal group, model group and Gastrodia elata polysaccharide group (50, 100 and 200 mg/kg). Except the normal group, the other groups were given high-fat diet to induce NAFLD model. At the same time, the corresponding drugs were given once a day for 10 weeks. At 30 min after the last administration, the body weight and organ index of mice were recorded, the pathological changes of liver tissue were evaluated by histopathology. At the same time, the activity of serum aspartate amino transferase (AST) and alanine amino transferase (ALT) were measured, and the related signal transduction pathways were examined including oxidative stress injury and lipid metabolism. Results:Compared with the model group, the activity of AST and ALT in serum were significantly decreased (P<0.05), and the pathological symptoms of fatty liver tissue was alleviated, and the level of genes expression related to lipid accumulation were regulated to improve lipid metabolism (P<0.05); In addition, Gastrodia elata polysaccharide also improved oxidative stress injury by upregulating Nrf2/GPX signaling pathway (P<0.05), inhibited the expression of NF-κB, TNF-α, IL-1β, iNOS and COX-2 proteins related to inflammatory response (P<0.05), and inhibited the expression of Bax and upregulated Bcl-2 proteins (P<0.05). Conclusion: Gastrodia elata Blume polysaccharide (GBP) can improve the liver function of NAFLD model mice, regulate the level of lipid metabolism and reduce the accumulation of fat, alleviate the oxidative stress injury of liver and inhibit inflammation to protect and delay NAFLD symptoms caused by high fat diet.