高脂饲养联合链脲佐菌素注射建立2型糖尿病大鼠模型的骨骼肌特征分析

Analysis of Skeletal Muscle Characteristics of Type 2 Diabetic Rats Induced by Hyperlipidemic Feeding Combined with Streptozotocin Injection

目的观察高脂饲养联合链脲佐菌素(STZ)注射建立2型糖尿病大鼠模型的基本特征,分析2型糖尿病大鼠的骨骼肌变化特征。方法采用9周高脂饲养建立外周胰岛素抵抗大鼠模型,辅以小剂量STZ注射构建2型糖尿病大鼠模型,分别于STZ注射前、STZ注射后持续6周取尾血测空腹血糖(FBG);STZ注射前、STZ注射后第2周、第6周测量胰岛素(FINS),计算胰岛素抵抗指数(HOMA-IR)和胰岛素敏感指数(ISI)。STZ注射后第6周取比目鱼肌ATP-ase染色观察并分析不同类型肌纤维萎缩情况。结果与对照组相比,糖尿病组大鼠体质量、FINS和ISI显著降低(P<0.01),FBG和HOMA-IR显著升高(P<0.01)。②STZ注射后,糖尿病组大鼠血糖逐渐升高,在第4周时趋于稳定;FINS显著降低,在第2周时趋于稳定。③2型糖尿病模型发展到第6周时,Ⅰ型肌纤维平均横截面积较对照组降低34.8%(P<0.01),Ⅱ型肌纤维平均横截面积降低幅度为14.1%(P<0.05)。结论9周高脂饲养联合STZ注射成功建立2型糖尿病大鼠模型,建模后第4周糖代谢指标趋于稳定,在第6周时表现出以Ⅰ型肌纤维萎缩为主的骨骼肌特征。

Objective To observe the characteristics of type 2 diabetic rats induced by hyperlipidemia and STZ injection,and analyze the changes of skeletal muscle in type 2 diabetic rats.Method Type 2 diabetic rats were established by 9 weeks high fat diet combined with streptozotocin(STZ)injection.Fasting blood glucose was measured before STZ injection and 6 weeks after STZ injection.Insulin was measured before STZ injection,2 weeks after STZ injection and 6 weeks after STZ injection.HOMA-IR and ISI were calculated by blood glucose and insulin.At the 6th week after STZ injection,ATP-ase staining of soleus muscle was used to observe and analyze the atrophy of different types of muscle fibers.Result Compared with the control group,the body weight,FINS and ISI of diabetic rats were significantly decreased(P<0.01),FBG and HOMA-IR were significantly increased(P<0.01).②After injection of STZ,the blood glucose of diabetic rats gradually increased and tended to be stable at the 4th week,while FINS decreased significantly and stabilized at the second week.③The average cross-sectional area of typeⅠmuscle fiber was decreased by 34.8%(P<0.01)and the average cross-sectional area of typeⅡmuscle fiber was decreased by 14.1%(P<0.05)compared with the control group at the 6th week after the development of type 2 diabetes mellitus model.Conclusion The rat model of type 2 diabetes was established successfully by 9 weeks high fat feeding and STZ injection,and the glucose metabolism index tended to be stable at the 4th week after modeling,and showed the skeletal muscle characteristics of type I muscle fiber atrophy at the 6th week.