家兔缺血再灌注肾组织胰岛素受体的分析

Radioligand binding assay of insulin receptor in rabbit kidney during ischemia and reperfusion

目的 :观察家兔急性缺血再灌注 (IR)后不同时相 ,肾组织胰岛素受体及血清胰岛素水平的变化。方法 :采用钳夹肾动脉的方法建造急性缺血再灌注肾损伤模型。实验动物分为对照组、缺血再灌注 (IR)组 ,测定两组动物的肾组织胰岛素受体、血糖和血清胰岛素水平。结果 :IR 2h时 ,对照组、IR组血清胰岛素水平均较术前显著升高 (P <0 0 5 ) ,但IR组胰岛素升高更为显著 (P <0 0 5vscontrol) ,4 8h时对照组胰岛素水平接近正常水平 ,IR组也明显低于 2h时 (P <0 0 5 ) ,但仍高于对照组 (P <0 0 5 )。IR 2h时 ,两组动物血糖均较术前增高 ,但以IR组增高更为显著 (P <0 0 5vscontrol)。放射性配基结合分析法中 ,Scatchard作图得到一下凹曲线。IR 2h ,IR组胰岛素高、低亲和力受体最大受体结合容量Bmax1和Bmax2 ,高、低亲和力常数Kd1和Kd2 均显著低于对照组 (P <0 0 5 )。 4 8h时 ,二组动物Kd1、Bmax1和Bmax2 无明显差异 ,但IR组Kd2 高于对照组 (P <0 0 5 )。结论 :实验结果显示 ,在肾IR过程中 ,内源性胰岛素的作用减弱 ,胰岛素受体数目的减少或与配体亲和力减弱。

AIM: To observe the change of insulin receptor in rabbit kidney with acute ischemic-reperfusion injury. METHODS: 15 Japanese white rabbits were allocated randomly into control group, ischemic-reperfusion group(IR group). IR group received clamping for 1 h followed by 2 h or 48 h of reperfusion. At 2 h or 48 h after reperfusion, glucose and insulin in serum were determined. Insulin receptor in renal tissue was analyzed by radioligand binging assay(BAD). RESULTS: The level of serum glucose increased after 2 h reperfusion in 2 groups, but in IR group the value increased much more higher than those in control groups(P<0.05). Plasma insulin of IR group was significantly higher than that in control after 2 h reperfusion(P<0.05). Scatchard analysis of data resulted in curvilinear profiles, indicating that there are two classes of receptors with different affinity or the presence of a single class of receptors with a negative cooperative hormone-receptor interaction. Data analyzed for a two-site model showed that the values of Bmax 1(high affinity site), Bmax 2(low affinity site) and Kd 1, Kd 2 were significantly lower than that of control (P<0.05) after 2 h perfusion. 48 h after IR there was no difference of Bmax 1, Bmax 2, and Kd 1 between 2 groups,but Kd 2 of IR group was higher than that of control (P<0.05). CONCLUSIONS: The results indicate that the effect of intrinsic insulin decreases in the progress of the renal ischemic-reperfusion. The resulting high serum glucose may aggravate renal injury in the progress of ischemic-reperfusion.