吡格列酮联合胰高血糖素样肽-1治疗对db／db糖尿病小鼠胰岛β细胞的影响

The protection of islet β-cells in db/db mice by combination pioglitazone and glucagon like peptide-1 treatment

目的评价胰高血糖素样肽类似物利拉鲁肽与胰岛素增敏剂吡格列酮联合治疗db／db小鼠糖尿病的效果。方法35只8周龄，体重（35．3±2．5）g的雄性db／db小鼠分为（1）对照组（n=8）：给予生理盐水0．1ml，2次／d；（2）吡格列酮组（n=9）：给予吡格列酮（饲料中含0．02％吡格列酮）＋生理盐水0．1ml，2次／d；（3）利拉鲁肽组（n=9）：给予利拉鲁肽300mg／kg，2次／d；（4）联合治疗组（n=9）：给予吡格列酮（饲料中含0．02％吡格列酮）＋利拉鲁肽300mg／kg，2次／d。利拉鲁肽用灭菌生理盐水稀释后皮下注射，每天8：00和16：00给药，持续4周。行腹腔注射葡萄糖耐量试验（IPGTr）和胰岛素耐量试验（ITT），评价胰岛B细胞的增殖。采用单因素方差分析进行数据统计分析。结果干预4周后，联合治疗组糖化血红蛋白（4．5±0．6）％，糖耐量试验血糖曲线下面积（18144-91）mmol·min·L^-1，游离脂肪酸（202．0±20．4）μmol／L，TG（0．81±0．28）mmol／L均明显低于对照组[（7．3±0．4）％，（4042±183）mmo]·min·L^-1，（272．5±21．7）μmol／L，（1．35±0．21）mmol／L]，P值均〈0．05；胰岛素曲线下面积（1639±372）汕g·min·L^-1，脂联素（16．7±2．0）mg／L，胰岛组织切片胰岛素阳性面积（59．5±1．5）％和胰岛新生13细胞比例（2．4±0．5）％均显著高于对照组[（834±201）μg·min·L^-1，（10．2±1．8）mg／L，（22．4±1．5）％和（0．8±0．3）％]，P值均〈0．05。且联合治疗组上述指标均低于或高于单药治疗组。联合治疗显著改善胰岛β细胞和α细胞分布，恢复正常的胰岛形态。结论吡格列酮联合利拉鲁肽治疗相比单药更好地改善db／db小鼠糖脂代谢，保护胰岛β细胞功能并促进其增殖。

Objectives To evaluate the effect peptide-1 analogue and pioglitazone, an insulin sensitizer, of combination of liraglutide, a glucagon-like on diabetic db/db mice. Methods Thirty-five 8-week old male db/db mice were divided into control group （ n = 8 ）, pioglitazone group （ n = 9 ） , liraglutide group （ n = 9） and combined therapeutic group （ n = 9）, which was given normal saline 0. 1 ml, 2/d, pioglitazone 24 mg · kg- l . d- 1 （ feed contained 0. 02% pioglitazone） ＋ normal saline 0. 1 ml, 2/d, liraglutide 300 mg/kg ,2/d, and pioglitazone 20 mg · kg-1 · d-1 （feed contained 0.02% pioglitazone） ＋ liraglutide 300 mg/kg, 2/d, respectively. Liraglutide were given at 8：00 and 16：00 via subcutaneous injection after having been diluted with sterilized normal saline. Effect on glucose, lipid metabolism and islet β-cell preservation were assessed after 4 weeks. Oneway ANOVA was adopted for statistical analysis. Results Combination therapy displayed promising anti-hyperglycemic [ glycosylated hemoglobin A1 c ： （4. 5±＋ 0. 6） % vs. （7.3 ±0. 4）% ,P 〈0. 0011. Glucose tolerance were improved assessed by area under curve（AUC） of glucose by intraperitoneal glucose tolerance test （IPGTT） [ （1814± 91 ） mmol · min · L-1 vs. （4042± 183） mmol ·min ·L-1, P 〈0. 001 ] ;insulin release response to glucose were also preserved as AUC of insulin by IPGTT was higher[ （1639 ±372） μg · min·L-1 vs. （834±201 ）μg · min · L-1 ]. Combinationtherapy also reduced circulated free fatty acids and TG [ （ 202. 0 ± 20. 4 ） μmol/L vs. （272. 5 ±21.7 ） μmol/L, （ 0. 81 ± 0. 28 ） mmol/L vs. （ 1.35 ± 0. 21 ） mmoL/L ] , and increased plasma adiponectin [ （16. 7 ±2. 0）mg,/L vs. （10. 2 ± 1.8） mg/L]. All P value 〈 0. 05. Islet immunohistochemistry showed that combination therapy significantly increased insulin positive area were [ （ 59. 5 ± 1.5 ） % vs. （ 22.4 ± 1.5 ） % ] and ratio of Brdu positive B-cells was three folds than vehicle-treated mice [ （ 2.4 ± 0. 5 ） % vs. （0. 8 ± 0. 3） % ], both greater than each single treatment. Combined therapy significantly improved islet β cell/α cell distribution, which led to islet recovery. Conclusions Combined therapy improves glucose and lipid metabolism, preserves islet β-cell function and stimulates β-cell proliferation, greater than either liraglutide or pioglitazone treatment alone.