Galasso J M, Miller M J, Cowell R M, Harrison J K, Warren J S, Silverstein F S
Neuroscience Program, University of Michigan, Ann Arbor, Michigan 48109-0646, USA.
Exp Neurol. 2000 Oct;165(2):295-305. doi: 10.1006/exnr.2000.7466.
Chemokines are a family of structurally related cytokines that activate and recruit leukocytes into areas of inflammation. The "CC" chemokine, monocyte chemoattractant protein (MCP)-1 may regulate the microglia/monocyte response to acute brain injury. Recent studies have documented increased expression of MCP-1 in diverse acute and chronic experimental brain injury models; in contrast, there is little information regarding expression of the MCP-1 receptor, CCR2, in the brain. In the neonatal rat brain, acute excitotoxic injury elicits a rapid and intense microglial response. To determine if MCP-1 could be a regulator of this response, we evaluated the impact of excitotoxic injury on MCP-1 and CCR2 expression in the neonatal rat brain. We used a reproducible model of focal excitotoxic brain injury elicited by intrahippocampal injection of NMDA (10 nmol) in 7-day-old rats, to examine injury-induced alterations in MCP-1 and CCR2 expression. RT-PCR assays demonstrated rapid stimulation of both MCP-1 and CCR2 mRNA expression. MCP-1 protein content, measured by ELISA in tissue extracts, increased >30-fold in lesioned tissue 8-12 h after lesioning. CCR2 protein was also detectable in tissue extracts. Double-immunofluorescent labeling enabled localization of CCR2 both to activated microglia/monocytes in the corpus callosum adjacent to the lesioned hippocampus and subsequently in microglia/monocytes infiltrating the pyramidal cell layer of the lesioned hippocampus. These results demonstrate that in the neonatal brain, acute excitotoxic injury stimulates expression of both MCP-1 and its receptor, CCR2, and suggests that MCP-1 regulates the microglial/monocyte response to acute brain injury.
趋化因子是一族结构相关的细胞因子，可激活白细胞并将其募集至炎症部位。“CC”趋化因子，即单核细胞趋化蛋白（MCP）-1，可能调节小胶质细胞/单核细胞对急性脑损伤的反应。最近的研究表明，在各种急性和慢性实验性脑损伤模型中，MCP-1的表达均增加；相比之下，关于MCP-1受体CCR2在脑中表达的信息却很少。在新生大鼠脑中，急性兴奋性毒性损伤可引发快速而强烈的小胶质细胞反应。为了确定MCP-1是否可能是这种反应的调节因子，我们评估了兴奋性毒性损伤对新生大鼠脑中MCP-1和CCR2表达的影响。我们使用了一种可重复的局灶性兴奋性毒性脑损伤模型，该模型通过向7日龄大鼠海马内注射NMDA（10 nmol）诱发，以检查损伤诱导的MCP-1和CCR2表达变化。逆转录-聚合酶链反应（RT-PCR）分析表明，MCP-1和CCR2 mRNA表达均受到快速刺激。通过酶联免疫吸附测定（ELISA）在组织提取物中测得的MCP-1蛋白含量，在损伤后8-12小时的损伤组织中增加了30倍以上。在组织提取物中也可检测到CCR2蛋白。双重免疫荧光标记能够将CCR2定位到与损伤海马相邻的胼胝体中活化的小胶质细胞/单核细胞，随后定位到浸润损伤海马锥体细胞层的小胶质细胞/单核细胞中。这些结果表明，在新生脑中，急性兴奋性毒性损伤可刺激MCP-1及其受体CCR2的表达，并提示MCP-1调节小胶质细胞/单核细胞对急性脑损伤的反应。
