胰岛素干预对糖尿病大鼠后肢缺血的作用及意义

Effect of Insulin Interventional Therapy on Hindlimb Ischemia of Rats with Diabetic

目的研究外源性胰岛素对糖尿病大鼠缺血后肢血管内皮生长因子(VEGF)表达的影响及其促血管新生的作用。方法取20只健康雄性SD大鼠,将其右后肢股动、静脉及其分支和属支结扎,制成糖尿病大鼠后肢缺血模型,然后将其用简单随机化方法随机平均分为模型组与治疗组,另取10只正常大鼠作为对照组。14 d后处死大鼠,应用Western blot法检测大鼠后肢肌肉组织中VEGF蛋白表达水平,并采用碱性磷酸酶(AKP)染色法测定大鼠后肢肌肉组织中毛细血管密度。结果对照组大鼠术前和术后7 d体重和血糖水平比较差异无统计学意义(P>0.05);模型组大鼠术后7 d与术前比较,体重明显下降(P<0.05),但血糖水平差异无统计学意义(P>0.05);而治疗组给予皮下注射胰岛素注射液术后7 d较术前体重明显下降,并且血糖水平较术前也明显下降,差异均有统计学意义(P<0.05)。与对照组比较,治疗组及模型组大鼠术后7 d体重明显下降、血糖明显升高(P<0.05,P<0.01);治疗组与模型组比较,体重差异无统计学意义(P>0.05),但治疗组大鼠术后7 d血糖水平较模型组明显降低(P<0.05)。治疗组大鼠缺血肢体肌肉组织中VEGF蛋白相对表达量(155.06±10.26)明显高于模型组(94.30±11.23),P<0.05;对照组大鼠未检测到VEGF蛋白表达。对照组大鼠右后肢肌肉组织中毛细血管密度明显高于模型组和治疗组(P<0.05),而治疗组又明显高于模型组(P<0.05)。3组大鼠左后肢毛细血管密度差异无统计学意义(P>0.05);对照组大鼠左、右后肢毛细血管密度差异无统计学意义(P>0.05);模型组和治疗组大鼠右后肢毛细血管密度均明显低于左后肢(P<0.05)。结论胰岛素可以增强糖尿病大鼠后肢缺血肌肉组织中VEGF蛋白表达,促进毛细血管生成,发挥保护作用。

Objective To study the effect of exogenous insulin on inducing angiogenesis and the expression of vascular endothelial growth factor （VEGF） of hindlimb ischemia of rats with diabetic. Methods The hindlimb is- chemic model of diabetic rat was established by the ligation of femoral blood vessels of hindlimb in twenty healthy male SD rats and which were divided into model group （n= 10） and treatment group （n=10）. Another 10 normal rats were selected as control group. Then the expression of VEGF protein and capillary density of muscle tissues of rat hindlimb were detected by Western blot analysis and alkaline phosphatase （APK） stain method, respectively. Results The differences of body weight and blood glucose level of rats before operation and on day 7 after operation were not significant in the control group （P〉0.05）. The body weight of rat was significantly lower on day 7 after operation than that before operation in the model group （P〈0.05）, while the difference of blood glucose level of rats was not significant in the model group （P〉0.05）. The body weight and blood glucose level of rat significantly de- creased in the treatment group on day 7 after subcutaneous injection of insulin as compared with the level before op- eration （P〈0.05）. Compared with the control group, the body weight decreased and blood glucose level increased in the model group and treatment group, and the difference was significant （P〈0.05, P〈0.01）. The body weight of rat in the treatment group was not different from that in the model group （P〉0.05）, but the blood glucose level of rat on day 7 after operation in the treatment group was significantly lower than that in the model group （P〈0.05）. The relative expression of VEGF protein of muscle tissues of ischemic hindlimbs in the treatment group （155.06±10.26） was significantly higher than that in the model group （94.30±11.23）, P〈0.05, while no expression was found in the control group. The capillary density of muscle tissues of right hindlimb in the control group was signifi- cantly higher than that in the model group or treatment group （P〈0.05）, and furthermore, which was higher in the treatment group than that in the model group （P〈0.05）. The difference of capillary density of muscle tissues of left hindlimb was not different among three groups （P〉0.05）. The capillary density of muscle tissues of right hindlimb was not different from that of left hindlimb in the control group （P〉0.05） and which was significantly lower than that of left hindlimb in the model group or treatment group （P〈0.05）. Conclusion Insulin may increase the expres- sion of VEGF porotein in ischemic muscle tissue of diabetic rats and protect the ischemie muscle.