磷脂酰肌醇3激酶及葡萄糖转运蛋白4在巴马小型猪2型糖尿病模型中的表达

Expressions of phosphatidylinositol 3-kinase and glucose transporter 4 in a Bama miniature pig model with type 2 diabetes mellitus

目的观察高脂高糖饮食联合链脲佐菌素（STZ）多次注射诱导巴马小型猪2型糖尿病（T2DM）模型糖脂代谢情况以及骨骼肌、肝脏、胰腺组织磷脂酰肌醇3激酶（P13-K）及葡萄糖转运蛋白4（GLUT4）的表达变化，探讨该模型的特征。方法10只健康雄性巴马小型猪，按随机数字表法分为对照组和糖尿病模型组，每组5只。T2DM模型组用高脂高糖饲料（蔗糖37％、猪油10％、胆固醇2％、普通饲料51％）喂养，11个月初腹腔注射STZ100mg／kg，1周后重复1次；对照组喂养普通饲料，同时腹腔注射等量柠檬酸-柠檬酸钠缓冲液。两组实验期为12个月。检测两组动物空腹血糖（FPG）、空腹胰岛素（FINS）及血脂水平，采用胰岛素抵抗指数（HOMA-IR）评价胰岛素抵抗（IR）情况，并检测骨骼肌、肝脏及胰腺组织P13-K及GLUT4的表达水平。结果给予高脂高糖饲料后模型组小型猪FPG、FINS、HOMA-IR、三酰甘油（TG）、总胆固醇（TC）、低密度脂蛋白胆固醇（LDL-C）水平较对照组明显升高，注射STZ后，模型组动物FPG较对照组明显升高（mmol／L：11．46±1．64比4．64±0．47），FINS水平较对照组明显降低（μU／mL：6．57±0．33比8．11±0．28），差异均有统计学意义（均P〈0．01）。模型组骨骼肌、肝脏及胰腺组织P13-K、GLUT4蛋白表达水平较对照组明显降低[骨骼肌：P13-K为（6．55±1．81）％比（13．16±3．66）％，GLUT4为（42．34±10．62）％比（116．10±15．57）％，肝脏：P13-K为（6．79±1．73）％比（14．17±3．73）％，GLUT4为（40．35±16．81）％比（126．17±13．73）％，胰腺：P13-K为（5．71±1．51）％比（10．39±2．57）％，GLUT4为（38．90±16．69）％比（73．41±16．39）％，P〈0．05或P〈0．01]。结论采用高脂高糖饲料联合STZ多次注射可以成功诱导巴马小型猪T2DM模型，模型组小型猪存在明显IR及糖脂代谢紊乱，且模型组骨骼肌、肝脏及胰腺组织P13-K、GLUT4蛋白表达水平降低。

Objective To establish a Bama miniature pig model with type 2 diabetes mellitus （T2DM） using a high-fat and high-sugar diet combined with streptozotocin （STZ） injection for many times to observe the changes of animal glucolipid metabolism as well as the expressions of phosphatidylinositol 3-kinase （PI3-K） and glucose transporter 4 （GLUT4） in skeletal muscle, liver and pancreatic tissues, and to discuss the model characteristics. Methods A total of 10 healthy male Bama miniature pigs were randomly divided into two groups： a control group and a diabetic model group （each n = 5）. The diabetic model group was fed with a high-fat and high-sugar diet （cane sugar 37%, lard oil 10%, cholesterol 2%, normal fodder 51%）, and accepted intraperitonea] injection of STZ 100 mg/kg at the beginning of the 1 lth month, and 1 week later the injection was repeated; while the control group was fed with a normal diet, and at the same time accepted intraperitoneal injection of equal volume of citric acid and sodium citrate buffer. The experimental period was 12 months in both groups. The levels of fasting plasma glucose （FPG）, fasting insulin （FINS） and serum lipids, as well as the PI3-K and GLUT4 expressions in the skeletal muscle, liver and pancreatic tissues of two groups were deteeted, and the insulin resistance index （HOMA-IR） was applied to evaluate the insulin resistance （IR）. Results After feeding with high-fat and high-sugar diet, the FPG, FINS, HOMA-IR, triglycerides （TG）, total cholesterol （TC）, and low-density ]ipoprotein cholesterol （LDL-C） levels of the miniature pigs in the model group were significantly higher than those in the control group. After injection of STZ, the FPC level in the model group was obviously higher than those in the control group （retool/L： 11.46 ± 1.64 vs. 4.64 ± 0.47）, and the FINS level was markedly lowered （ μU/mL： 6.57 ± 0.33 vs. 8.11± 0.28）, the differences being statistically significant （both P 〈 0.01）. The PI3-K and CLUT4 expression levels of the skeletal muscle, liver and pancreas in the model group were statistically lower than those in control group [skeletal muscle： PI3-K was （6.55 ±1.81）% vs. （13.16 ± 3.66）%, GLUT4 was （42.34 ± 10.62）% vs. （116.10 ± 15.57）%;liver： PI3-K was （6.79 ± 1.73）% vs. （14.17 ± 3.73）%, GLUT4 was （40.35 ± 16.81）% vs. （126.17 ±13.73）%; pancreas： PI3-K was （5.71 ± 1.51）% vs. （10.39±2.57）%, GLUT4 was （38.90± 16.69）% vs. （73.41 ±16.39）%, P 〈 0.05 or P 〈 0.01]. Conclusions The high-fat and high-sugar diet combined with STZ injection for many times can successfully establish a Bama miniature pig model with T2DM. The miniature pigs in the model group show significant IR and glucolipid metabolism disorder, and the levels of PI3-K and GLUT4 protein expressions in the skeletal muscle, liver and pancreatic tissues of the miniature pigs in the model group were reduced.