局灶性脑缺血再灌注损伤大鼠脑、肝中IGF-1的动态表达及其意义

Significance and changes of IGF-1 expression in brain and liver of rats with focal cerebral ischemia reperfusion injury

目的探讨胰岛素样生长因子-1（IGF-1）在局灶性脑缺血再灌注损伤大鼠脑、肝中的表达变化及其意义。方法采用线栓法制备大鼠局灶性脑缺血再灌注模型，应用免疫组化染色方法检测大鼠脑缺血再灌注后2h、1d、3d、7d时脑、肝标本中IGF-1蛋白的含量。结果正常脑组织有低水平的IGF．1表达，脑缺血再灌注后2h后表达即有明显升高，1d时持续升高，至3d时达高峰，7d时又有所回落，其表达主要位于大脑皮质区。经方差分析，脑组织中IGF-1蛋白含量脑缺血再灌注组与对应各时间点假手术组比较差异均有统计学意义（P〈0．051；假手术组各时间点比较差异无统计学意义（P〉0．05）；脑缺血再灌注组1d和7d间比较差异无统计学意义（P〉0．05），其余脑缺血再灌注组各时间点间比较差异均有统计学意义（P〈0．05）。正常肝组织中有极低水平IGF-1表达，脑缺血再灌注2h、1d、3d后肝组织中IGF-1蛋白含量与假手术组各对应时间点比较差异无统计学意义（P〉0．05），脑缺血再灌注7d时与脑缺血再灌注组其余各时间点及假手术组对应时间点比较差异均有统计学意义fP〈0．05）。结论脑缺血再灌注损伤后大鼠脑、肝中内源性IGF-1水平有明显变化，提示IGF-1的变化与脑缺血再灌注损伤有关联。

Objective To study the expression of insulin-like growth factor-1 （IGF-1） in brain and liver of rat with focal cerebral ischemia reperfusion injury. Methods The focal cerebral ischemia models were induced in rats by the filament method, and the expression of IGF-1 protein in brain and liver of rats was detected by the method of immunohistochemical staining 2 h, 1, 3, 7 d after reperfusion. Results The expression of IGF-1 was low in normal tissues of brain, while increased markedly 2 h after reperfusion, peaked on day 3 after reperfusion, fell back on day 7. The expression of IGF- 1 protein was mainly located in cerebral cortex after cerebral ischemia. ANOVA analysis revealed that there were significant differences in the number of IGF-1 positive cells between model group and sham-operation group at same time point （P〈0.05）, however, there was no significant difference in IGF-1 expression between different time points in sham-operation group （P〉0.05）. The difference of IGF-1 expression between different reperfusion time points in model group was significant （P〈0.05） except for between 1 d and 7 d （P〉0.05）. The expression of IGF-1 was very low in normal tissues of liver, and the number of IGF- 1 positive cells in liver was not increased significantly at 2 h and 1, 3 d after reperfusion in the model group as compared with that in the sham-operation group （P〉0.05）. But the number of IGF-1 positive cells in liver at 7 d after reperfusion in the model group was increased significantly as compared with that in the sham-operation group and the other time points in model group （P〈0.05）. Conclusion There are obvious changes in IGF- 1 expression in rat brain and liver after cerebral ischemia reperfusion, indicating that IGF- 1 may play a role in cerebral ischemia reperfusion injury.