血管紧张素转化酶2对高脂饲养的ApoE-/-小鼠保护内皮、改善胰岛素抵抗及抑制肝脏纤维化的实验观察

An experimental observation of angiotensin converting enzyme 2 on protecting endothelium,improving insulin resistance and inhibiting liver fibrosis in ApoE-/- mice fed with high-fat diet

目的研究携带血管紧张素转换酶2（ACE2）基因的重组腺病毒载体（Ad-ACE2）转染对高脂饲养的载脂蛋白E基因敲除（ApoE-/-）小鼠保护内皮、改善胰岛素抵抗及抑制肝脏纤维化的影响。方法用高脂高能量饲料喂养ApoE-/-小鼠,模拟代谢综合征。30只ApoE-/-小鼠随机分为对照组（Con组）、ACE2基因对照组（EGFP组）和ACE2基因治疗组（ACE2组）,每组10只,均给予高脂饮食。3组分别通过尾静脉注射生理盐水、Ad-EGFP和Ad-ACE2干预。12周末行葡萄糖耐量试验和胰岛素耐量试验。小鼠麻醉后,心尖取血,测定血脂水平。取肝脏组织进行HE染色、油红O染色。免疫组织化学染色观察肝组织ACE2、Ⅰ型胶原蛋白（COL-Ⅰ）、Ⅲ型胶原蛋白（COL-Ⅲ）、白细胞介素6（IL-6）表达。结果用Ad-ACE2转染的ACE2组显著提高了ApoE-/-小鼠肝脏中ACE2的表达（P〈0.05）,ACE2组内皮依赖性功能明显优于Con组和EGFP组（P〈0.05）,胰岛素敏感性强于Con组和EGFP组（P〈0.05）,而血脂水平无明显改变。ACE2组肝脏组织中COL-Ⅰ、COL-Ⅲ、IL-6表达均低于Con组和EGFP组（P〈0.05）。结论 ACE2过表达能够保护内皮,改善胰岛素抵抗,抑制肝脏纤维化,从而保护肝脏功能。

Aim To investigate the effect of transfection of recombinant adenovirus vector carrying angiotensin converting enzyme 2（ ACE2） gene（ Ad-ACE2） on protecting endothelium,improving insulin resistance and inhibiting liver fibrosis in apolipoprotein E knock-out（ ApoE-/- ） mice fed with high-fat diet. Methods ApoE-/- mice were fed with high-fat and high-energy food to simulate metabolic syndrome. 30 ApoE-/- mice were randomly divided into control group（ Con group）,adenovirus empty vector group（ EGFP group） and ACE2 gene therapy group（ ACE2 group）,with 10 mice in each group,and each group was given a high-fat diet. The 3 groups were injected respectively with normal saline,Ad-EGFP and Ad-ACE2 by intravenous injection of the tail vein. At the end of 12 weeks,glucose tolerance test and insulin tolerance test were carried out. After the mice anaesthesia,blood was extracted from heart tip and blood lipid level wasserve the expressions of ACE2,collagen-Ⅰ（ COL-Ⅰ）,collagen-Ⅲ（ COL-Ⅲ） and interleukin-6（ IL-6） in liver tissue.Results In ACE2 group,Ad-ACE2 transfection significantly increased the expression of ACE2 in ApoE-/- mice liver（ P〈0.05）. The endothelium-dependent function in ACE2 group was significantly better than that in Con group and EGFP group（ P〈0.05）,and insulin sensitivity was stronger than that in Con group and EGFP group（ P〈0.05）,but the level of blood lipid did not change significantly. The COL-Ⅰ,COL-Ⅲ and IL-6 expressions of liver tissue in ACE2 group were lower than those in Con group and EGFP group（ P〈 0.05）. Conclusion ACE2 overexpression can protect the endothelium,improve insulin resistance,inhibit liver fibrosis and thus protect liver function.