2型糖尿病大鼠氧化应激与骨骼肌细胞葡萄糖转运蛋白4转位相关性的研究

Correlation study between oxidative stress and translocation of glucose transporter 4 in the skeletal muscle cells in type 2 diabetic mellitus rats

目的研究2型糖尿病大鼠氧化应激与骨骼肌细胞葡萄糖转运蛋白4转位间的相关性。方法雄性SD大鼠40只,按照体重随机分为模型组、对照组和正常组。采用左下腹注射链脲佐菌素(STZ)50 mg·kg^(-1)并结合高脂高糖饮食,制备2型糖尿病大鼠模型。对照组和正常组,注射相同剂量的柠檬酸缓冲液,对照组喂以高脂高糖饲料,正常组喂以普通饲料。3个月后,处死各组动物,心脏取血,分离血清,以正常组和对照组作为对照,检测模型组各项生化指标和氧化应激指标;用免疫印迹法检测骨骼肌细胞GLUT4的转位。结果正常组和模型组的空腹血糖分别为(5.59±1.04),(36.68±11.95)mmol·L^(-1)、三酰甘油分别为(0.86±0.54),(2.73±2.13)mmol·L^(-1)、总胆固醇分别为(1.65±0.29),(3.08±1.35)mmol·L^(-1)、空腹胰岛素分别为(18.09±3.41),(133.68±42.87)m U·L^(-1)、CAT分别为(24.25±2.17),(5.96±2.69)U·mg^(-1)protein、MDA分别为(6.12±1.25),(20.25±0.71)nmol·mg^(-1)protein、Mn-SOD分别为(40.96±1.24),(35.58±1.44)U·mg^(-1)protein、GSH-PX分别为(366.05±29.95),(297.65±10.39)U·mg^(-1)protein,模型组大鼠各项生化指标和氧化应激水平与正常组比较差异有统计学意义(P<0.01)。模型组、对照组和正常组大鼠骨骼肌细胞膜GLUT4表达水平分别为1.03±0.02,0.42±0.13,0.18±0.05,模型组和对照组大鼠骨骼肌细胞膜GLUT4表达水平与正常组比较差异有统计学意义(P<0.01)。模型组大鼠的骨骼肌细胞膜GLUT4含量与CAT之间的相关系数为0.815(P<0.01),与MDA之间的相关系数为-0.798(P<0.01),与Mn-SOD之间的相关系数为0.799(P<0.01),与GSH之间的相关系数为0.752(P<0.01)。结论氧化应激对2型糖尿病大鼠骨骼肌细胞GLUT4转位有抑制作用,并且胞膜GLUT4表达水平与氧化应激存在相关性。

Objective To study the correlation between oxidative stress and transloeation of glucose transporter 4 in the skeletal muscle cells in type 2 diabetic mellitus rats. Methods Forty male SD rats were randomly divi-ded into three groups： model group, control group and normal group. The model of type 2 diabetes mellitus was developed by injection of streptozotocin （ STZ, 50 mg·kg^- 1 ） combined with high - fat - sugar diet. The control group and normal group were treated by a single injection of citrate buffer solution in same dose. The control group was fed with high -fat - sugar diet and normal group was fed with normal diet. Rats were killed three months later, and cardiac serum was isolated to detect biochemical and oxidative stress markers of the model group with the control group and normal group as control. The translocation of GLUT4 was detected by Western blot. Results The biochemical and oxidative stress markers in normal and model groups ： FPG were （ 5.59 ± 1.04 ）, （36.65±11.95） mmol·L^-1 TG were （0.86±0.54） （2.75±22.15） mmol ·L^-1 TC were （1.65±20.29） （3.08 ± 1.35） mmol ·L^-1, FINS were （ 18.09±3.41 ）, （ 133.68±242. 87） mU ·L^-1, CAT were （24.25± 22. 17）, （5.96 ± 2.69 ） U · mg^-1 protein, MDA were （6. 12 ± 1.25 ）, （20. 25 ± 0. 71 ） nmol · mg^- 1 protein, Mn - SOD were （40.96±1.24）, （35.58 ± 1.44） U · mg^-1 protein, GSH-PX were （366.05 ±29,95）, （297.65± 10.39） U · mg^-1 protein, respectively and the levels of these markers in model group were significantly higher than those in normal group （P 〈 0. 05 ）. The expression level of GLUT4 in skeletal muscle membrane of normal group, control group and model group were （ 1.03 ± 0. 02）, （0. 42 ± 0. 13 ） and （0. 18 ± 0. 05 ）, and the expression of GLUT4 significantly decreased in control and model groups compared with normal group （P 〈 0. 01 ）. Moreover, there was a significant correlation between GLUTg in skeletal muscle cytoplasm and CAT （r = -0. 815, P 〈 0. 01 ）, MDA （r = -0. 798, P〈0.01）, Mn-SOD （r=0.799, P〈0.01） andGSH （r=0. 752,P〈0. O1）. Conclusion Oxidative stress could inhibit the translocation of GLUT4 in skeletal muscle of type 2 diabetic mellitus rats, and there was a correlation between GLUT4 expression level in cytoplasm and oxidative stress.