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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、室管膜细胞、皮层和海马的星形胶质细胞、血管内皮细胞均表达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。
Objective To investigate the effect of cerebral ischemia on the expression of ceruloplasmin (Cp) in rat cortex and hippocampus. Methods Sixty male Wistar rats were randomly divided into three groups: 1, 3, 7, 28 d, and sham operation group, 12 rats in each group. In the experimental group, bilateral common carotid arteries were ligated to cause cerebral ischemia in rats. In the sham operation group, bilateral common carotid arteries were isolated but not ligated. The expression of Cp mRNA in cortex and hippocampus was detected by reverse transcriptase-polymerase chain reaction (RT-PCR), and the expression of Cp in cortex and hippocampus was observed by immunohistochemistry. Results Both rat cortex and hippocampus expressed Cp mRNA. The expression of Cp mRNA in cortex and hippocampus gradually decreased with the prolongation of ischemia time, and the expression of Cp mRNA in cortex and hippocampus was lower than that in sham operation group at 1, 3, 7 and 28 days (P <0.01). Cp of choroidal plexus cells, ependymal cells, astrocytes of cortex and hippocampus and vascular endothelial cells were expressed in brain tissue, but neither of pyramidal cells nor granular cells in cortex and hippocampus expressed Cp. The expression of Cp in cortex and hippocampus of ischemic 1 d group was not significantly different from that in control group (P> 0.05). The expression of Cp in cortex and hippocampus of ischemic 3 d group was lower than that in sham operation group (P <0.05) Cp decreased significantly (P <0.01). The content of iron in the cortex and hippocampus of cerebral ischemia rats was negatively correlated with the expression of Cp, the correlation coefficients were -0.831 (P <0.01) and -0.809 (P <0.01) respectively. Conclusions Cerebral ischemia can induce a decrease of Cp in rat cortex and hippocampus. The decreased expression of Cp after cerebral ischemia may be involved in the process of cerebral ischemia-induced elevated iron content and neuronal iron deposition.