Objective: To explore effects of cerebral ischemia on the ceruloplasmin (Cp) expression in the cortex and hippocampus of rats.
Methods: Male Wistar rats were randomly divided into cerebral ischemia group and control group. Cerebral ischemia was induced by ligating bilateral common carotid arteries and the ischemic rats were further subgrouped according to ischemia time. The control rats received a sham operation. The expression of Cp mRNA in the cortex and hippocampus was measured by reverse transcription polymerase chain reaction (RT-PCR). The Cp expression was shown by immunohistochemistrical (streptavidin peroxidase, SP) method.
Results: In ischemia group, the expression of Cp mRNA in the cortex and hippocampus decreased compared with that in control group (P< 0.01); and the longer rats experienced cerebral ischemia, the lower Cp mRNA expressed. By immunohistochemistry, Cp was shown expressed in the neural cells including epithelial cells of choroid plexus, ependymal cells, astrocytes of cortex and hippocampus, and vascular endothelial cells, but not in pyramidal cells and granulosa cells of cortex and hippocampus. Cp levels in the cortex and hippocampus decreased in rats suffering from cerebral ischemia for 3 d, 7 d and 28 d but not in rats exposed to ischemia for 1 d compared with that in control group (P< 0.05). Iron concentration correlated negatively with Cp expression in the cortex and hippocampus of rats exposure to ischemia (the cortex, r = -0.831, P< 0.01; the hippocampus, r = -0.809, P< 0.01).
Conclusion: Cerebral ischemia inhibited Cp expression in the cortex and hippocampus of rats. The decrease of Cp might be involved in iron deposition in neurons.
目的: 探讨脑缺血对大鼠皮层及海马中铜蓝蛋白 (Ceruloplasmin, Cp) 表达的影响。
方法: 雄性 Wistar 大鼠 60 只, 随机分为脑缺血 1、 3、 7、 28 d 组和假手术对照组, 每组各 12 只。 实验组结扎双侧颈总动脉造成大鼠脑缺血, 假手术对照组仅分离出双侧颈总动脉但不结扎。 采用反转录聚合酶链反应 (RT-PCR) 检测皮层及海马组织中 Cp mRNA 的表达, 免疫组织化学观察皮层及海马组织中 Cp 的表达。
结果: 大鼠皮层和海马均表达 Cp mRNA。 皮层和海马 Cp mRNA 的表达随缺血时间的延长逐渐降低, 缺血 1、 3、 7、 28 d 组表达均低于假手术组 (P < 0.01)。 脑组织脉络丛细胞、 室맜膜细胞、 皮层和海马的星形胶质细胞、 血맜内皮细胞均表达 Cp; 而皮层和海马的锥体细胞和颗粒细胞均不表达 Cp。 缺血 1 d 组皮层及海马 Cp 表达与对照组差异不显著 (P > 0.05); 缺血 3 d 组皮层和海马 Cp 表达低于假手术组 (P < 0.05); 缺血第 7、 28 d 组 Cp 表达减少极为显著 (P < 0.01)。 脑缺血大鼠皮层和海马中铁含量与 Cp 的表达呈负相关, 相关系数分别为 −0.831 (P < 0.01) 和 −0.809 (P < 0.01)。
结论: 脑缺血可诱导大鼠皮层及海马中 Cp 表达降低。 脑缺血后 Cp 表达减少可能参与了脑缺血引起的铁含量升高及神经元铁沉积的过程。