ANALYSIS OF MULTIFUNCTION OF MICROGLIA IN THE ISCHEMIA-RELATED NEURONAL DEATH

小胶质细胞在缺血相关神经元死亡中的多功能分析

基本信息

批准号：
13670090
负责人：
SAKURAI Yasuko
金额：
$ 2.24万
依托单位：
NAGASAKI UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13670090/
关键词：
ISCHEMIA-RELATED NEURONAL DEATH MICROGLIA ASTROCYTES MCP-1 ET_B RECEPTOR BLOOD BRAIN BARRIER

项目摘要

We have studied the mechanism of ischemia-related neuronal death leading to dementia. Our previous results demonstrated that microglia expressing endothelin ETB (ETB) receptor aggregated in the pyramidal layer of the hippocampus where the selective neuronal death occurred. We tried to induce ischemia in the spotting lethal (sl) rats with lack of the ETB gene expression. As the rats homozygous for this mutation die shortly due to the congenital distal aganglionosis, they were legated an unilateral carotid artery and exposed to hypoxia at 2 weeks old according to the neonatal ischemia model. The ipsilateral pyramidal cells were lost in both ETB^<+/+> and ETB^<sl/sl> and the process was different from that in SHRSP because of the clear histochemical damage at 24h after reperfusion in the neonatal model. Then we investigated the expression of monocyte chemoattractant protein-1 (MCP-1) because our previous study showed the increased permeability of blood brain barrier (BBB) at 24h after the ischemia-reperfusion in SHRSP. MCP-1 mRNA was expressed in the astrocytes of dentate gyrus at 24h after 10 min-ischemia and distributed in the CA1 subfield at 48h. The expressing cells at 48h in the CA1 subfield was almost astrocytes. Increased MCP-1 protein concentration was also demonstrated in the hippocampus at 48h by ELISA. Cultured astrocytes were used to clarify the induction of MCP-1 after the in vitro ischemic condition, aglycemia/hypoxia by astrocytes themselves. Expression of MCP-1 mRNA was dramatically increased in the astrocytes from SHRSP, however a little in those from WKY, normotensive rats. These results suggest that MCP-1 expressed in astrocytes after the ischemia-reperfusion might make monocytes migrate into the brain and also activate microglia. The substances to inhibit the secretion or function of MCP-1 could inhibit the delayed neuronal death induced by a transient global ischemia in SHRSP.

我们研究了缺血相关神经元死亡导致痴呆的机制。我们之前的结果表明，表达内皮素 ETB (ETB) 受体的小胶质细胞聚集在发生选择性神经元死亡的海马锥体层中。我们尝试在缺乏 ETB 基因表达的斑点致死 (sl) 大鼠中诱导缺血。由于该突变的纯合子大鼠因先天性远端无神经节细胞病而很快死亡，因此根据新生儿缺血模型，将它们置于单侧颈动脉并在2周龄时暴露于缺氧环境。 ETB^<+/+>和ETB^<sl/sl>均出现同侧锥体细胞丢失，其过程与SHRSP不同，因为新生儿模型再灌注24h时出现明显的组织化学损伤。然后我们研究了单核细胞趋化蛋白-1（MCP-1）的表达，因为我们之前的研究表明SHRSP缺血再灌注后24小时血脑屏障（BBB）通透性增加。缺血10 min后24 h，MCP-1 mRNA在齿状回星形胶质细胞中表达，48 h分布于CA1亚区。 48h CA1 亚区表达细胞基本为星形胶质细胞。 ELISA 还显示 48 小时后海马中 MCP-1 蛋白浓度增加。培养的星形胶质细胞用于阐明星形胶质细胞本身在体外缺血条件、血糖/缺氧后对 MCP-1 的诱导。 SHRSP 的星形胶质细胞中 MCP-1 mRNA 的表达显着增加，但 WKY、血压正常大鼠的星形胶质细胞中的表达略有增加。这些结果表明，缺血再灌注后星形胶质细胞中表达的MCP-1可能使单核细胞迁移到大脑中并激活小胶质细胞。抑制MCP-1分泌或功能的物质可以抑制SHRSP短暂性整体缺血引起的迟发性神经元死亡。