胃转流术对GK大鼠肝脏脂代谢的影响及其意义

目的:探讨胃转流术对自发性糖尿病Goto-Kakizaki(GK)大鼠肝脏脂代谢的影响及其意义。方法:40只雄性GK大鼠随机均分为实验组与对照组。实验组行Roux-en-Y胃转流术,对照组行胃窦十二指肠离断原位吻合术。分别于术前、术后1,2,4周检测两组大鼠空腹血糖、口服葡萄糖耐量试验2 h(OGTT 2 h)的血糖;并于术前及术后4周测定大鼠血液中空腹游离脂肪酸(FFA),胆固醇(Tch),甘油三酯(TG)。此外,于术中及术后第4周获取大鼠肝脏组织行免疫组化油红O染色,观察肝脏TG沉积情况。结果:与术前比较,实验组大鼠术后空腹及OGTT 2 h血糖值均呈下降趋势,两者在术后2,4周时明显降低(均P<0.05);术后第4周,实验组大鼠血液中FFA明显降低(P<0.05),而TG及Tch无明显变化(均P>0.05),肝脏组织切片内TG沉积现象明显减少。对照组以上所有指标手术前后均无明显改变(均P>0.05)。结论:胃转流术降低GK大鼠血糖的机制可能与改善肝脏脂质代谢,降低FFA含量,使胰岛素抵抗得以缓解有关。

Effect of gastric bypass surgery on hepatic lipid metabolism in GK rats and its significance

Objective: To investigate the effect of gastric bypass procedure on hepatic lipid metabolism in spontaneous diabetic Goto-Kakizaki (GK) rats and its significance.Methods: Forty male GK rats were equally randomized into experimental group and control group. Rats in experimental group underwent Roux-en-Y gastric bypass operation while rats in control group underwent antroduodenal transaction and then, reanastomosis in situ. The fasting glucose and 2-h oral glucose tolerance test (2-h OGTT) glucose value of the two groups were measured before and 1 week, 2 and 4 weeks after surgery respectively, and the fasting blood levels of free fatty acids (FFA), total cholesterol (Tch) and triglyceride (TG) of rats before and 4 weeks after surgery were also measured. In addition, liver tissues of rats obtained intraoperatively and 4 weeks after surgery were used for immunohistochemical oil red O staining to observe the TG deposits in the liver. Results: Compared with those before surgery, the values of both fasting glucose and 2-h OGTT glucose showed a gradually declining trend after surgery in experimental group, which decreased significantly at 2 and 4 weeks after surgery (all P<0.05); in experimental group, the blood FFA level significantly decreased (P<0.05), while there were no significant changes in the TG and Tch level (both P>0.05), but the TG accumulation in the liver tissue section was markedly reduced. All of the above parameters and measurements in control group showed no obvious changes after surgery compared with preoperative values (all P>0.05).Conclusion: The blood sugar-lowering effect of gastric bypass procedure may be probably associated with its improving hepatic lipid metabolism and decreasing FFA concentration, thereby ameliorating the insulin resistance.