中文摘要：

目的探讨利拉鲁肽对db／db小鼠胰腺及大鼠胰岛细胞瘤细胞系INS-1中microRNA表达的影响。方法将20只4周龄雄性db／db小鼠按随机数字表法分为对照组和利拉鲁肽组（每组10只）。分别给予0．1ml生理盐水或300ng／g利拉鲁肽皮下注射，每E12次。8周后测定糖化血红蛋白，行腹腔注射葡萄糖耐量试验（TPGTT）。8周末处死小鼠，免疫组化法分析小鼠胰腺B细胞增殖水平；实时荧光定量聚合酶链反应（RT-PCR）测定小鼠胰腺microRNA（miR．375和miR-34a）的表达。INS-1细胞分别给予0．5mmol/L棕榈酸培养0、48、72h或100nmol／L利拉鲁肽预处理12h后，给予0．5mmol／L棕榈酸培养72h，RT—PCR测定miR-375和miR-34a表达水平。采用t检验及方差分析进行组间数据比较分析。结果与对照组相比，利拉鲁肽组小鼠糖化血红蛋白水平降低（分别为7．3％±0．3％和4．7％±0．6％，t=16．47，P〈0．01）；IPGTT血糖曲线下面积降低[分别为（4568-4-197）和（1927±127）mmol·L-1·min-1，t=26．53，P〈0．05]；胰岛素曲线下面积增加[分别为（1080±247）和（2818±378）μg·L-1·min-1，t=7．73，P〈0．05]。免疫组化法显示，与对照组相比，利拉鲁肽组小鼠胰岛素阳性面积增加（分别为1．40±0．30和0．37±0．09，t=19．14，P〈0．01），Brdu染色阳性细胞比例增加（分别为2．40％±0．22％和0．73％±0．10％，t=4．97，P〈0．01）。利拉鲁肽组小鼠胰腺miR-375与miR-34a表达较对照组分别降低50％（分别为1．1±0．3和2．2±0．5，t=3．08，P〈0．05）和71％（分别为1．1±0．3和3．8±1．2，t=2．80，P〈0．05）。棕榈酸培养使INS-1细胞miR-375表达呈剂量、时间依赖性增加，利拉鲁肽可抑制棕榈酸诱导的miR-375表达（F=7．20，P〈0．01）。结论microRNA可能是利拉鲁肽调节β细胞增殖的靶点之-。

英文摘要：

Objective To investigate the effect of glucagon-like peptide 1 analogue liraglutide on microRNA expression of db/db mice and rat insulinoma cell line （ INS-1 ）. Methods Twenty 4-week old male db/db mice were randomly assigned to receive a subcutaneous injection of liraglutide （300 ng/g bid）or normal saline （0. 1 ml bid） （ control group） according to random numbers table. Glycated hemoglobin （HbAlc） was determined before and after 8 weeks of intervention. At the end of the intervention, intraperitoneal glucose tolerance test （IPGTT） was performed. Beta cells proliferation rate was determined by using immunohistochemistry methods. INS-1 cells were cultured with 0. 5 mmol/L palmitic acid for 0, 48, 72 h or treated by 100 nmol/L liraglutide for 12 h before 72 h of palmitic acid（0. 5 mmol/L） culture. microRNA miR-375 and miR-34a expression were examined by real-time polymerase chain reaction （RT- PCR）. The t test or ANOVA analysis was used for data analysis. Results Compared with the control group, HbAlc in the liraglutide group was significantly lower （7.3% ± 0. 3% vs 4. 7%± 0. 6%, t = 16.47, P 〈 0. 01 ）; the glucose aera under curve in the liraglutide group was decreased significantly （（4568±197） vs （1927 ±127） mmol · L-1· min-1, t =26.53, P 〈0.05） , while insulin aera under curve was increased significantly （ （1080 ±247） vs（2818±378） μg· L-1· min-1, t =7. 73,P 〈0. 05）. Immunohistochemistry showed more insulin staining in single pancreas of db/db mice after liraglutide treatment than in the control group （ 1.40 ±0. 30 vs 0. 37±0. 09 ,t = 19. 14, P 〈0. 01 ）. More Brdu-positive cells were observed in islets of liraglutide-treated mice than in control mice after intervention （2.40%± 0. 22% vs 0. 73% ± 0. 10% ,t = 4. 97, P 〈 0.01 ）. Compared with control mice, the miR-375 expression of pancreas in liraglutide-treated db/db mice was reduced by 50% （ 1.1 ± 0. 3 vs 2. 2 ±0. 5, t = 3.08, P 〈 0.05 ） and miR-34a was reduced by