沙棘多糖对急性肝损伤小鼠氧化应激的抑制作用及其对BCL－2／Bax和PPAR－γ的调控

摘要

Objective:To explore the inhibitory effects of seabuckthorn polysaccharide on hepatic oxidative stress in a mice model of acute liver injury induced by intraperitoneal injection of LPS and D -GalN and detect the expression on hepatic BCL-2/Bax and PPAR-γ.Methods: C57BL/6 male mice were randomly divided into six groups:control group ( CTRL), model group ( L/G), dexamethasone positive control group ( DXM ) , low ( SPL ) , medium ( SPM ) and high dose group ( SPH ) of seabuckthorn polysaccharide.Mice in the SPL,SPM and SPH group were gavaged with 50,100 and 200 mg/kg seabuckthorn polysaccharide for 14 days respectively.Acute liver injury model were established by intraperitoneal injection of LPS (10 μg/kg) and D-GalN (700 mg/kg) .Serum and liver samples were collected 4 h after model establishment .Serum levels of ALT and AST and the content of MDA were de-tected.Hepatic expression of SOD 2 BCL-2 and Bax was determined by Western blot and the expression of PPAR-γwas detected by im-munohistochemistry .Results:ALT and AST levels significantly increased in the model group and decreased dose-dependently after pre-treatment with seabuckthorn polysaccharide .The level of MDA in the model group increased significantly as compared with the control group and decreased in seabuckthorn polysaccharide groups ,while the level of SOD 2 decreased in the model group and recovered in sea-buckthorn polysaccharide groups .The expression of Bax decreased after pretreatment with seabuckthorn polysaccharide .There was no obvious effect on BCL-2 expression after sea buckthorn polysaccharide supplementation .The expression of PPAR-γreduced in the sea-buckthorn polysaccharide group as compared with the model group .Conclusion:Seabuckthorn polysaccharide protects against LPS /D-GalN-induced liver injury.The effect is associated with an upregulation of SOD 2 and downregulation of Bax .%目的：以LPS／D－GalN诱导的小鼠急性肝损伤作为模型，研究沙棘多糖对急性肝损伤的保护作用及其对BCL－2／Bax和PPAR－γ的调控。方法：C57 BL／6系雄性小鼠随机分为六组：正常组（ CTRL ）；模型组（ L／G ）；地塞米松阳性对照组（ DXM）；沙棘多糖低（ SPL）、中（ SPM）、高剂量组（ SPH）。 SPL、SPM和SPH组分别用50、100、200 mg／kg沙棘多糖溶液连续灌胃14 d，然后采用D－GalN（700 mg／kg）联合LPS（10μg／kg）腹腔注射诱导急性肝损伤。建模4 h后采集血清和并收集肝脏组织，检测ALT、AST的活性和丙二醛（ MDA）的含量。通过Western blot检测肝脏组织中SOD2及BCL－2和Bax的表达水平。通过免疫组织化学法测定肝脏PPAR－γ的表达。结果：ALT、AST水平在模型组显著升高（ P＜0．01），沙棘多糖预处理后剂量依赖地降低了ALT和AST水平（ P＜0．01）；模型组的MDA比正常组显著升高（ P＜0．01），沙棘多糖各剂量组比模型组都有显著降低（ P＜0．01）。模型组的SOD比正常组显著降低（ P＜0．01），沙棘多糖各剂量组比模型组都有显著升高（ P＜0．01）；沙棘多糖预处理后降低了Bax的表达水平，对BCL－2的表达没有明显的影响。沙棘多糖各剂量组中PPAR－γ的表达量与模型组相比明显降低。结论：沙棘多糖对LPS／D－GalN诱导的氧化应激有抑制作用，其作用与上调SOD2的表达以及抑制Bax的表达有关。