课题背景：血管紧张素转化酶2作为血管紧张素转化酶的同源酶，在肾素-血管紧张素系统中起重要的负向调节作用。课题观察了氧化低密度脂蛋白对血管紧张素转化酶及血管紧张素转化酶2的影响。

应用要点：文章采用反转录-聚合酶链反应及蛋白质免疫印迹方法，检测氧化型低密度脂蛋白对人脐静脉内皮细胞血管紧张素转化酶及血管紧张素转化酶2表达的影响，结果发现氧化型低密度脂蛋白显著上调血管紧张素转化酶蛋白及基因表达，下调血管紧张素转化酶2蛋白及基因表达，且呈剂量和时间依赖性。

同行评价：新近研究发现血管紧张素转化酶2与血管紧张素转化酶在功能上相拮抗。课题采用反转录-聚合酶链反应及Western blot方法，观察氧化型低密度脂蛋白对人脐静脉内皮细胞血管紧张素转化酶及血管紧张素转化酶2表达的影响，文章设计合理，数据可靠。

摘要
目的：新近研究发现血管紧张素转化酶2与血管紧张素转化酶在功能上相拮抗。采用反转录-聚合酶链反应及蛋白质免疫印迹方法，观察氧化型低密度脂蛋白对人血管内皮细胞血管紧张素转化酶及血管紧张素转化酶2表达的影响。
方法：实验于2007-05/08在南方医科大学附属珠江医院中心实验室完成。①用正常人新鲜血浆制备氧化低密度脂蛋白，人脐静脉内皮细胞株复苏、传代后取生长良好的3~6代用于实验。②实验分为7组：空白对照组加无血清培养基；20，40，80 mg/L氧化型低密度脂蛋白组分别与人脐静脉内皮细胞孵育24 h；40 mg/L氧化型低密度脂蛋白分别与人脐静脉内皮细胞孵育6，12，24 h。各组实验重复6次。③提取细胞总RNA及蛋白，应用反转录-聚合酶链反应检测血管紧张素转化酶、血管紧张素转化酶2 mRNA表达水平；以蛋白质免疫印迹法检测血管紧张素转化酶、血管紧张素转化酶2蛋白表达水平。
结果：①与空白对照组比较，氧化低密度脂蛋白20，40，80 mg/L组血管紧张素转化酶 mRNA表达增加，血管紧张素转化酶2 mRNA表达降低(P < 0.01)，不同剂量组间差异亦有显著性意义(P均 < 0.01)。40 mg/L氧化型低密度脂蛋白6，12，24 h组血管紧张素转化酶 mRNA表达增加，血管紧张素转化酶2 mRNA表达减少(P < 0.05)，不同时间点间差异亦有显著性意义(P均 < 0.05)。②与空白对照组比较，氧化低密度脂蛋白20，40，80 mg/L组血管紧张素转化酶蛋白表达增加，血管紧张素转化酶2蛋白表达减少(P < 0.01)，不同剂量组间差异亦有显著性意义(P均 < 0.01)。40 mg/L氧化型低密度脂蛋白6，12，24 h组血管紧张素转化酶蛋白表达增加，血管紧张素转化酶2蛋白表达降低 (P < 0.05)，不同时间点间差异亦有显著性意义(P均< 0.05)。
结论：氧化型低密度脂蛋白可上调血管紧张素转化酶蛋白及基因表达，下调血管紧张素转化酶2蛋白及基因表达，且呈剂量和时间依赖性。
关键词：脂蛋白类；肽基二肽酶A；内皮，血管；脐静脉/细胞学

周鹏，李志樑，徐春生，严全能，宋旭东，付强，陈文忠. 人脐静脉内皮细胞血管紧张素转化酶及血管紧张素转化酶2表达与氧化型低密度脂蛋白的关系[J].中国组织工程研究与临床康复，2008，12(20):3869-3873
[www.zglckf.com/zglckf/ejournal/upfiles/08-20/20k-3869(ps).pdf]

Abstract
AIM: Present studies have confirmed that angiotensin-converting enzyme (ACE) 2 has contrary function as ACE. Reverse transcription-polymerase chain reaction (RT-PCR) and Western blot were used to investigate the effect of oxidized low-density lipoprotein (ox-LDL) on the expressions of ACE and ACE2 in human vascular endothelial cells (hVECs).
METHODS: Experiments were performed at the Central Laboratory of Zhujiang Hospital of Southern Medical University from May to August 2007. ox-LDL was produced from human fresh plasma. Human umbilical vein endothelial cells (hUVECs) of 3rd-6th passages were rolled into the experiment. Cells in the blank control group were treated with serum-free medium. Cells in the 20, 40, 80 mg/L ox-LDL groups were separately inoculated with hUVECs for 24 hours. 40 mg/L ox-LDL were separately inoculated with hUVECs for 6, 12, 24 hours. Experiment was repeated six times in each group. Total RNA and protein were extracted. mRNA and protein expressions of ACE and ACE2 were respectively determined by RT-PCR and Western blot.
RESULTS: Compared to the blank control group, ACE mRNA expression increased, whereas ACE mRNA expression decreased in the 20, 40, 80 mg/L ox-LDL groups (P < 0.01). Significant differences were detected in different doses of groups (P < 0.01). ACE mRNA expression increased, whereas ACE mRNA expression decreased in the 40 mg/L ox-LDL groups at 6, 12, 24 hours (P < 0.05). Significant differences were detected at different time points (P < 0.05). Compared to the blank control group, ACE protein expression increased, whereas ACE protein expression reduced in the 20, 40, 80 mg/L ox-LDL groups (P < 0.01). Significant differences were detected in different doses of groups (P < 0.01). ACE protein expression increased, whereas ACE protein expression reduced in the 40 mg/L ox-LDL groups at 6, 12, 24 hours (P < 0.05). Significant differences were detected at different time points (P < 0.05).
CONCLUSION: Ox-LDL up-regulates the protein and gene expression of ACE and down-regulates the protein and gene expression of ACE2 in a concentration and time dependent manner.

Zhou P, Li ZL, Xu CS, Yan QN, Song XD, Fu Q, Chen WZ. Correlation of angiotensin converting enzyme and angiotensin converting enzyme 2 expressions to oxidized low-density lipoprotein in human umbilical vein endothelial cells.Zhongguo Zuzhi Gongcheng Yanjiu yu Linchuang Kangfu 2008;12(20):3869-3873(China)
[www.zglckf.com/zglckf/ejournal/upfiles/08-20/20k-3869(ps).pdf]