MACROPHAGES/MICROGLIA AND CSPGS IN SPINAL CORD INJURY

超过25万美国人由于急性脊髓损伤(SCI)而严重和永久残疾。目前尚无促进慢性脊髓损伤患者神经功能恢复的治疗方法。这项拟议的研究将检验中心假设，即巨噬细胞/小胶质细胞表达抑制脊髓损伤后轴突生长的基质分子，并且这些假定的抑制分子的阻断将促进轴突再生。为了挑战这一假说，我们将致力于以下具体目标：1)利用原位杂交和免疫标记技术确定CSPG蛋白多糖表达的细胞来源，以及应用蛋白多糖抑制剂β-D-木糖苷抑制蛋白多糖合成是否能促进脊髓损伤后轴突的生长；2)采用半定量聚合酶链式反应测定经生长因子和细胞因子处理的巨噬细胞在体外是否调节其CSPG的表达；以及3)确定转基因成纤维细胞移植后是否会减少ECM分子的沉积，促进轴突修复。在这里，将使用转基因细胞传递、免疫标记、原位杂交和神经解剖示踪。

Over 250,000 Americans are severely and permanently disabled due to acute spinal cord injuries (SCI). There currently is no therapy for promoting recovery of neurological function in chronic stages of SCI. The proposed study will test the central hypothesis that macrophages/microglia express matrix molecules that inhibit axonal outgrowth after SCI, and that the blockade of these putative inhibitory molecules will augment axonal regeneration. To challenge this hypothesis, the following Specific Aims will be addressed: 1) Determine the cellular source of CSPG proteoglycan expression using in situ hybridization and immunolabelling, and whether the inhibition of proteoglycan synthesis by application of the proteoglycan inhibitor beta-D- xyloside enhances axonal outgrowth after SCI; 2) Determine using semi-quantitative PCR whether macrophages treated with growth factors and cytokines modulate their expression of CSPGs in vitro; and 3) Determine whether grafts of fibroblasts genetically modified to express and secrete augmented amounts of inhibitory cytokines (e.g., interleukin 10 or other substances identified in Aims 2) will reduce the deposition of ECM molecules and promote axonal repair after SCI. Here, transgenic cellular delivery, immunolabeling, in situ hybridization and neuroanatomical tracing will be used.