短暂性脑缺血再灌注对大鼠脑PGRN表达的影响

目的检测短暂性脑缺血再灌注早期,大鼠的额颞叶皮质、海马及纹状体中颗粒蛋白前体(progranulin,PGRN)的表达变化,为进一步探讨PGRN对脑缺血的治疗提供实验基础。方法 SPF级成年SD大鼠随机分为2组,假手术组(shamoperation group)和实验组(MCAO group)。用线栓法制作右侧大脑中动脉阻塞(MCAO)1 h,然后再灌注30 min、2 h、12 h、24 h模型,以缺血侧为实验组(ipsilateral group),其对侧为对照组(contralateral group)。假手术组为处理对照。用TTC染色法观察缺血梗死体积。用免疫荧光组织化学法和Western-blot分别检测PGRN的细胞定位及其表达变化。结果 TTC染色表明,脑缺血区域呈现白色,而对照无缺血区为红色。免疫组织化学结果提示,PGRN在神经元中大量表达,在小胶质细胞中有少量表达,而在星形胶质细胞中几乎无表达。Western blot结果提示,与对照组相比,缺血再灌注后2 h大鼠脑额颞叶皮质的缺血侧与非缺血侧PGRN含量均显著上调。在海马区缺血再灌注能瞬间降低PGRN水平,随着时间延长PGRN表达水平在24 h逐步恢复到正常水平。与皮质和海马相比,纹状体在短时间再灌注后PGRN具有较高的表达,特别是在缺血再灌注24 h后。结论短暂性脑缺血再灌注能显著影响PGRN在大鼠脑缺血区及半暗带区的水平,提示PGRN可能参与缺血后脑的调节。

Effects of transient ischemia-reperfusion injury on cerebral PGRN expression in adult rat

Objective This study aims to investigate the expression profile of progranulin(PGRN) in the frontal and temporal cortex,hippocampus and striatum of the rats after transient cerebral ischemia and reperfusion.This study will provide the basic experimental data for further investigate the roles of PGRN in brain ischemia.Methods SPF class SD rats were used to produce MCAO-reperfusion models by insertion of nylon filaments and withdrawal at indicated times.The right Common Carotid Artery(CCA) and Internal carotid artery(ICA) of the rat were isolated and inserted with nylon filaments to model the brain ischemia.The ischemic hemisphere was considered as ipsilateral group.The other side was considered as the contralateral group.The non-filament inserted surgery rat were regards as sham group.Then TTC staining was used to exhibit the infarct size after MCAO-reperfusion.Immunohistofluorescence and Western-blot methods were used to detect the cellular localization and expression of PGRN.Results TTC staining showed the ischemic part of the hemisphere was red,the contralateral hemisphere was white without no ischema.Immunohistofluorescence analysis showed PGRN was mainly expressed in the neurons and the majority of microglias and scarcely expressed in the astrocytes of the cerebrum.Western blot data showed compared with the sham surgery group,the expression of PGRN was significantly increased in the frontal and temporal cortex both in the ipsilateral and contralateral sides after MCAO at 2hr.In the hippocampus the PGRN expression was transiently decreased in the ipsilateral hemisphere,then draw back in both ischemic and non-ischemic parts at 24 hr.Compared with PGRN in cortex and hippocampus,the PGRN expression was highly enhanced both in ipsilateral side and in contralateral side in the striatum,especially for the ipsilateral side at 24 hr.Conclusion The transient ischemia-reperfusion injury can significantly influence the expression of PGRN in both ischemic region and penumbra of the brain,which indicated PGRN maybe plays an important role in the regulation of ischemic brain.