摘要
目的应用高脂喂养分别诱导胰岛素抵抗(IR)和糖尿病(DM)伴发非酒精性脂肪肝(NAFLD)小鼠模型,探讨肝脏微小RNA-21(miR-21)表达改变在NAFLD发病中的作用。方法实验分3组:对照组、IR组和DM组;记录小鼠体质量,腹腔糖耐量实验确定糖代谢异常,行肝脏病理切片检查,检测空腹血糖、血清胰岛素、血脂、肿瘤坏死因子α含量的变化,检测肝脏miR-21表达和肝脏过氧化物酶体增殖物激活受体亚型(PPAR-γ、PPAR-α)和脂肪型脂肪酸结合蛋白(a P2)基因和蛋白表达改变。结果 IR组体质量、血清胰岛素水平和稳态模型胰岛素抵抗指数较对照组明显上升(P<0.01,P<0.05),DM组空腹血糖浓度上升,而血清胰岛素水平明显下降(P<0.05),其他指标较对照组差异无统计学意义(P>0.05);IR组血清胰岛素水平较对照组增加而DM组明显降低(P<0.01,P<0.05);IR组和DM组葡萄糖曲线下面积较对照组显著增加(P<0.01)。IR组和DM组血清肿瘤坏死因子-α水平呈明显上升趋势(P<0.05,P<0.01)。IR组和DM组伴随着NAFLD加重,肝脏组织miR-21表达水平进一步下调(P<0.05),与IR组PPAR-α、a P2和PPAR-γ基因表达上调呈负相关(r值分别为-0.696、-0.664和-0.766,P<0.05),与DM组PPAR-α和PPAR-γ基因表达上调也呈负相关(r值分别为-0.676和-0.550,P<0.05);蛋白表达改变仅IR组PPAR-γ和a P2较对照组明显上调(P<0.05,P<0.01)。结论 IR和DM伴发NAFLD时肝组织均出现miR-21表达降低,可能通过调节PPAR-α和PPAR-γ的基因表达参与NAFLD发病。
Objective To investigate the roles of microRNA-21（ miR-21） in the pathogenesis of nonalcoholic fatty liver disease（ NAFLD） with high-fat diet-induced insulin resistance（ IR） and diabetes mellitus（ DM） mice model. Methods Eight-week-old C57BL/6 mice were allocated into control group,IR group,and DM group. Body mass was recorded. Intraperitoneal glucose tolerance test was performed to determine any abnormal glucose metabolism. The liver pathological changes were detected by biopsy. Changes in free blood glucose,free serum insulin,blood fat and tumor necrosis factor α level were measured. Differences in miR-21 expression and peroxidase proliferator-activated receptor subtypes（ PPAR-γ and PPAR-α） and adipocyte fatty acid binding protein（ a P2） in the liver were detected both at the mRNA and protein levels. Results After one 8-week high-fat diet,the body mass,free serum insulin,and homeostasis model IR index significantly increased in the IR group（ P〈 0. 01,P〈 0. 05,compared with control group）,while the free blood glucose increased and the free serum insulin decreased in DM group（ P〈 0. 05）. Free serum insulin level were significantly increased in IR group（ P〈 0. 05）. Serum tumor necrosis factor-α levels exhibited an upward trend in control group,IR group,and DM group（ P〈 0. 05,P 〈0. 01）. With exacerbation in NAFLD,liver miR-21 expression level went further down in both IR and DM groups（ P〈 0. 05）. The downregulated miR-21 expression level showed negative correlation with upregulated PPAR-α,αP2,and PPAR-γ genetic expression（ r =- 0. 696,r =- 0. 664,and r =- 0. 766,respectively; P 〈0. 05） in IR group and with upregulated PPAR-α and PPAR-γ genetic expression in DM group（ r =- 0. 676 and r =- 0. 550,respectively; P〈 0. 05）. In terms of the changes in protein expression level,only on the protein expressions of a P2 and PPAR-γ in IR group showed significant change（ P 〈0. 05,P 〈0. 01,compared with control group）. Conclusions The miR-21 expression is downregulated in both IR and DM-induced NAFLD mice. It may be involved in the pathogenesis of NAFLD by regulating the expressions of PPAR subtypes.
出处
《中国医学科学院学报》
CAS
CSCD
北大核心
2016年第2期144-149,共6页
Acta Academiae Medicinae Sinicae
