胃转流术对2型糖尿病大鼠肠道菌群及部分血清指标的影响

Effect of gastric bypass surgery on intestinal flora and some serum indexes in rats with type 2 diabetes mellitus

目的观察胃转流术(gastric bypass,GBS)对自发性2型糖尿病大鼠(GK大鼠)肠道菌群及部分血清指标的影响,探讨其改善胰岛素抵抗的机制。方法 30只8周龄雄性GK大鼠采用随机数字法分为GBS手术组、假手术组及饮食配对组(n=10)。另10只8周龄雄性SD大鼠作为空白对照组(自由进食及饮水)。检测和比较术前及术后4周各组大鼠空腹血糖(FPG)水平及空腹胰岛素(FINS)水平,计算术前及术后4周胰岛素抵抗指数(HOMA-IR)。术前及术后4周取大鼠新鲜粪便并提取DNA,通过实时聚合酶链反应(RT-PCR)技术检测各组术后4周肠道菌群组成。结果术后4周,GBS手术组FPG水平由术前的(13.83±0.35)mmol/L下降至(5.73±0.21)mmol/L(P<0.05),GBS手术组HOMA-IR由术前的(5.71±0.27)mmol/L下降至(2.15±0.17)mmol/L(P<0.05),厚壁菌门(Firmicutes)(22.71±12.81)(P=0.020)、肠杆菌科(Enterobacterium spp.)(3.11±4.17)(P=0.043)的DNA含量明显减少,拟杆菌门(Bacte-roidetes)(30.74±17.33)(P=0.013)的DNA含量明显增加。结论 GBS可下调2型糖尿病大鼠肠道中厚壁菌门、肠杆菌科及上调拟杆菌门含量,改善大鼠机体胰岛素抵抗,提高胰岛素的敏感性。

Objective To observe the effect of gastric bypass (GBS) on intestinal flora and some serum indexes in spontaneous type 2 diabetic rats (GK rats), and to explore the mechanism of improving insulin resistance. Methods 30 Goto-Kakizaki rats, aged 8 weeks, were randomly divided into GBS operation group, sham operation group and diet matching group (n=10). Another 10 8-week-old male SD rats served as blank control group (free eating and drinking). The levels of fasting blood glucose (FPG) and fasting insulin (FINS) were measured and compared before and 4 weeks after operation. The insulin resistance index (HOMA-IR) was calculated before and 4 weeks after operation. Fresh feces of rats were collected 4 weeks after operation and DNA was extracted. The intestinal flora composition of each group was detected by real-time polymerase chain reaction (RT-PCR) at 4 weeks after operation. Results Four weeks after operation, FPG level in GBS group decreased from (13.83±0.35) mmol/L to (5.73±0.21) mmol/L (P<0.05), HOMA-IR in GBS group decreased from (5.71±0.27) to (2.15±0.17)(P<0.05). The DNA content of Firmicutes (22.71±12.81)(P=0.020), Enterobacterium spp.(3.11±4.17)(P=0.043) decreased significantly, and the DNA content of Bacteroides (30.74±17.33)(P=0.013) increased significantly. Conclusion GBS can down-regulate the intestinal thick-walled bacterium, Enterobacteriaceae and up-regulate the content of mimetic bacterium in type 2 diabetic rats, improve insulin resistance and insulin sensitivity.