宫内发育迟缓致大鼠肝细胞胰岛素敏感性降低及体外胰岛素抵抗模型的建立

Decreased insulin sensitivity in rat hepatocytes with intrauterine growth retardation and establishment of insulin resistance cell model in vitro

目的:探讨宫内发育迟缓(intrauterine growth retardation,IUGR)大鼠肝细胞胰岛素敏感性的变化情况,初步建立体外胰岛素抵抗模型。方法:采用孕期低蛋白饮食法建立IUGR大鼠模型,分别于仔鼠生后60 d和90 d,测定空腹血糖和空腹胰岛素,计算胰岛素抵抗指数(homeostasis model assessment-insulin resistance,HOMA-IR)和胰岛素敏感指数(insulin sensitivity index,ISI)。采用两步胶原酶灌注法获取大鼠肝细胞,分为对照组肝细胞和IUGR组肝细胞,对照组肝细胞设定两个平行组,分别为正常对照组和胰岛素诱导组。采用不同浓度胰岛素体外作用于正常大鼠肝细胞,确定建立胰岛素诱导组的最佳作用浓度。采用CCK-8方法检测肝细胞活力,葡萄糖氧化酶法测定肝细胞葡萄糖摄取率来评价肝细胞胰岛素敏感性。比较对照组、IUGR组及胰岛素诱导组肝细胞活力及葡萄糖摄取率。结果:IUGR鼠出生后60 d和90 d HOMA-IR均显著高于对照组(t=-17.02,P<0.05;t=-12.52,P<0.05),而ISI则显著低于对照组(t=5.61,P<0.05;t=12.42,P<0.05)。生后60 d和90 d,培养原代大鼠肝细胞48 h时对照组、IUGR组和胰岛素诱导组间肝细胞活力差异无统计学意义(F=1.34,P=0.29;F=0.22,P=0.81)。生后60 d和90 d,IUGR组和胰岛素诱导组肝细胞葡萄糖摄取率均低于对照组,3组间差异有统计学意义(F=9.28,P=0.002;F=56.60,P<0.001),但IUGR组和胰岛素诱导组间差异无统计学意义(P=0.08,P=0.10)。结论:IUGR大鼠青年期肝细胞的胰岛素敏感性已有所降低,并持续至成年期;高浓度胰岛素可诱发体外正常大鼠肝细胞产生胰岛素抵抗。

Objective：To explore the hepatocyte insulin sensitivity of intrauterine growth retardation （ IUGR） rats and establish an insulin resistance cell model in vitro.Methods： An IUGR animal model was established by protein malnutrition during the mother pregnancy .On 60 d and 90 d after birth , the offspring rats were fasted for 12 hours and then their angular vein blood was collected to measure the fasting plasma glucose and fasting serum insulin level , then the insulin resistance index （ HOMA-IR） and insulin sensitivity index （ ISI） were calculated .The insulin sensitivity was evaluated by HOMA-IR and ISI.Primary hepatocytes from each group were respectively isolated by two-step perfusion with collage-nase and were defined as normal hepatocytes group and IUGR hepatocytes group .The normal hepatocyte group was divided into two groups： control group and insulin induction group .Insulin induction group was established by primary cultures of normal hepatocyte incubated with varying dilutions of insulin . CCK-8 was used to detect the viability of the cultured hepatocytes .Glucose oxidase-peroxidase method kit was used to measure glucose consumption of the hepatocytes .Results：HOMA-IR was significantly higher in IUGR rats than in the normal rats at the age of 60 days （ t=-17 .02 , P〈0 .05 ） and 90 days （ t=-12.52, P〈0.05）.ISI was significantly lower than in the normal rats aged 60 days （t=5.61, P〈0.05） and 90 days （t=12.42, P〈0.05）.There were no significant differences in hepatocyte viability among the control group , IUGR group and insulin induction group after incubation of 48 h on day 60 （F=1.34, P=0.29） and day 90 （F=0.22, P=0.81）.The glucose consumption of the IUGR group and insulin induction group were significantly decreased compared with the control group on day 60 （ F=9.28, P=0.002） and day 90 （F=56.60, P〈0.001）, while there was no significant difference be-tween the IUGR group and insulin induction group （P=0.08, P=0.10）.Conclusion：The insulin sen-sitivity of hepatocytes of IUGR rats decreased from adolescence to adulthood .High-dilution insulin may induce insulin resistance cell model in vitro.