CAJ | 학술논문

目的探讨高脂饲养大鼠胰腺甘油三酯沉积与胰岛β细胞胰岛素抵抗的关系及其机制.方法 40只8周龄健康雄性SD大鼠(体质量160～170 g)按数字表法随机分为高脂饲料组(n=20)和常规饲料组(n=20),分别给予高脂饲料(热量构成为:碳水化合物占20%,蛋白质占21%,脂肪占66%)和常规饲料(热量构成为:碳水化合物占64%,蛋白质占23%,脂肪占13%).20周时空腹采血,检测血糖及胰岛素水平.大鼠麻醉后摘取胰腺组织,测定血液及胰腺组织甘油三酯含量.胰腺组织切片行苏木素伊红染色,观察胰岛形态.行胰岛细胞表面灌注实验,评价离体胰岛β细胞动态分泌功能.行正常血糖高胰岛素钳夹实验,评价外周组织胰岛素抵抗程度.采用实时荧光定量聚合酶链反应检测胰岛素受体底物-1、胰岛素受体底物-2、磷酯酰肌醇3激酶和葡萄糖转运蛋白-2mRNA表达水平.两组间比较采用t检验,相关性分析采用Pearson相关分析法.结果高脂饲料组空腹胰岛素、血液和胰腺组织甘油三酯水平均显著高于常规饲料组(t值分别为2.73、2.89、4.35,均P＜0.01),胰岛内可见脂质沉积.高脂饲料组葡萄糖输注率明显低于常规饲料组[分别为(5.2±1.2)、(13.6±1.7)mg·min-1·kg-1,t=6.48,P＜0.01];葡萄糖刺激的胰岛素分泌明显降低,峰值增高比例不及对照组的1/4(t=7.36,P＜0.01);胰岛β细胞胰岛素受体底物-1、胰岛素受体底物-2、磷酯酰肌醇3激酶、葡萄糖转运蛋白-2mRNA表达分别下降42.3%(t=8.53)、28.1%(t=3.94)、16.8%(t=2.79)、22.9%(t=5.62,均P＜0.05).相关性分析显示,胰腺组织甘油三酯水平与胰岛β细胞胰岛素受体底物-1、胰岛素受体底物-2 mRNA表达呈负相关(r值分别为-0.623、-0.537,均P＜0.05).结论高脂饲养可导致大鼠胰岛β细胞胰岛素信号转导分子基因表达下降,可能与胰腺组织甘油三酯异位沉积有关.
목적 탐토고지사양대서이선감유삼지침적여이도β세포이도소저항적관계급기궤제.방법 40지8주령건강웅성SD대서(체질량160～170 g)안수자표법수궤분위고지사료조(n=20)화상규사료조(n=20),분별급여고지사료(열량구성위:탄수화합물점20%,단백질점21%,지방점66%)화상규사료(열량구성위:탄수화합물점64%,단백질점23%,지방점13%).20주시공복채혈,검측혈당급이도소수평.대서마취후적취이선조직,측정혈액급이선조직감유삼지함량.이선조직절편행소목소이홍염색,관찰이도형태.행이도세포표면관주실험,평개리체이도β세포동태분비공능.행정상혈당고이도소겸협실험,평개외주조직이도소저항정도.채용실시형광정량취합매련반응검측이도소수체저물-1、이도소수체저물-2、린지선기순3격매화포도당전운단백-2mRNA표체수평.량조간비교채용t검험,상관성분석채용Pearson상관분석법.결과 고지사료조공복이도소、혈액화이선조직감유삼지수평균현저고우상규사료조(t치분별위2.73、2.89、4.35,균P＜0.01),이도내가견지질침적.고지사료조포도당수주솔명현저우상규사료조[분별위(5.2±1.2)、(13.6±1.7)mg·min-1·kg-1,t=6.48,P＜0.01];포도당자격적이도소분비명현강저,봉치증고비례불급대조조적1/4(t=7.36,P＜0.01);이도β세포이도소수체저물-1、이도소수체저물-2、린지선기순3격매、포도당전운단백-2mRNA표체분별하강42.3%(t=8.53)、28.1%(t=3.94)、16.8%(t=2.79)、22.9%(t=5.62,균P＜0.05).상관성분석현시,이선조직감유삼지수평여이도β세포이도소수체저물-1、이도소수체저물-2 mRNA표체정부상관(r치분별위-0.623、-0.537,균P＜0.05).결론 고지사양가도치대서이도β세포이도소신호전도분자기인표체하강,가능여이선조직감유삼지이위침적유관.
Objective To study the mechanism of ectopically fat deposition in the islets of high-fatdiet rat models and its relationship with islet beta-cell insulin resistance. Methods Forty healthy male SD rats (weight 160 to 170 g,8-week old) were randomly assigned to the high-fat-diet (HF) and the normal diet (NC) groups. Rats of the HF group ( n =20) were fed with high fat diet and rats of the NC group ( n =20) were fed with normal diet. At 20 weeks,fasting blood glucose (FBG) ,fasting serum insulin ( Ins),and triglyceride (TG) in the blood were determined. Glucose infusion rate (GIR) was measured by using euglycemic hyperinsulinemia clamp. The rats were then sacrificed,and the pancreatic islets were isolated and collected. TG in the pancreas was determined. The islet cell perfusion was conducted to evaluate the function of isle beta-cells. The mRNA expression of insulin receptor substrate-1 ( IRS-1 ),insulin receptor substrate-2 (IRS-2),phosphatidylinositol-3-kinase (PI3K),and glucose transporter-2 (GLUT-2) in islets were detected by real-time polymerase chain reaction. Student' s t test and Pearson correlation analysis were used for data analysis. Results The Ins and TG levels in the HF group were significantly higher than those in the NC group ( t values were 2. 73,2. 89,and 4. 35; all P＜0.01 ). The pancreas of high-diet group showed an increased storage of lipids. The GIR was significantly decreased in the HF group when compared stimulated insulin secretion was impaired in the high-fat-diet rats ( t = 7. 36,P ＜ 0. 01 ). The mRNA expressions of IRS-1,IRS-2,PI3K,and GLUT-2 were significantly decreased by 42.3% (t = 8.53),28. 1% (t =3.94),16.8% (t =2.79) and 22.9% (t =5.62,all P ＜0.05). There was a strongly negative correlation between TG level of the pancreas and IRS-1 or IRS-2 mRNA expression (r vales were - 0. 623 or - 0. 537,both P ＜ 0. 05 ). Conclusion High-fat-diet rat models show an impaired expression of insulin signal transduction molecules in islet beta-cells,which may be correlated with the fat deposition in the pancreas.