MECHANISMS AND PREVENTION OF HEMOGLOBIN NEUROTOXICITY

血红蛋白神经毒性的机制和预防

• 批准号: 2230780
• 负责人: Samuel Scott Panter
• 金额: $ 21.67万
• 依托单位: NORTHERN CALIFORNIA INSTITUTE/RES/EDU
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-09-01 至 1998-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2230780
• 关键词: antioxidants; ascorbate; astrocytes; blood /plasma substitute; blood proteins; calcium channel blockers; central nervous system; cerebellar cortex; chelating agents; drug screening /evaluation; haptoglobins; hemoglobin; immunochemistry; laboratory rat; microglia; neurons; neurotoxins; northern blottings; protein purification; stress proteins; tissue /cell culture

Hemoglobin-based compounds are being developed as blood substitutes to be used in surgery or emergency medicine, yet the consequences of placing hemoglobin-based compounds in direct contact with CNS tissue are unknown. These studies will continue to develop a cell culture model that can be used to assess the toxicity of hemoglobin or hemoglobin-based compounds to the CNS. Additionally, this model can be utilized to identify and test possible therapeutic approaches for the treatment of hemoglobin-mediated cellular injury. Previous results suggest that hemoglobin is neurotoxic. Oxyhemoglobin causes cerebral vasospasm, and intracortical injections of hemoglobin have been used to generate animal models of epilepsy. Preliminary experiments have demonstrated that both hemoglobin and a hemoglobin-based oxygen carrier are toxic to cultured murine neurons in a concentration-dependent fashion. This toxicity developed over time and progressed even after hemoglobin was removed. None of the hemoglobin solutions tested have appeared to be toxic to murine glial cells. The current proposal will address hemoglobin-mediated injury in cultures of rat cerebellar neurons, cortical neurons, pure astrocytes, and co- cultures of astrocytes and microglia. The concentration dependence and time course of hemoglobin-mediated injury will be delineated. Specific plasma proteins will be evaluated as protectants, emphasizing proteins that bind and facilitate the clearance of hemoglobin or heme--haptoglobin or hemopexin. Other compounds that may have therapeutic potential for the treatment of hemoglobin-mediated injury will be evaluated. These compounds will include antioxidants (such as Trolox, alpha tocopherol, and the 21- aminosteroids), chelators (such as deferoxamine and a novel deferoxamine derivative), as well as drugs that block the calcium entry into neurons (NMDA, kainate/AMPA, and metabotropic receptor antagonists and calcium channel blockers). Additional experiments will be conducted to test the hypotheses that ascorbate- and hemoglobin-dependent neurotoxicity are mediated through similar mechanisms and that ascorbate may exacerbate hemoglobin-mediated injury. Finally, the expression the of heat shock proteins HSP7O and heme oxygenase- l will be examined in neurons and astrocytes during the course of hemoglobin- and ascorbate-dependent injury. These proteins, which are thought to be protective, may be induced differently in different cells, partially explaining the differential sensitivity of neurons and astrocytes to hemoglobin.

正在开发基于血红蛋白的化合物作为血液替代品 用于手术或急诊医学，但放置的后果 与中枢神经系统组织直接接触的基于血红蛋白的化合物尚不清楚。 这些研究将继续开发一种细胞培养模型 用于评估血红蛋白或血红蛋白基化合物的毒性 中枢神经系统。此外，该模型可用于识别和测试 治疗血红蛋白介导的疾病的可能治疗方法 细胞损伤。 先前的结果表明血红蛋白具有神经毒性。氧合血红蛋白 引起脑血管痉挛，皮质内注射血红蛋白有 被用来产生癫痫动物模型。初步实验 已经证明血红蛋白和基于血红蛋白的氧 载体对培养的小鼠神经元具有浓度依赖性毒性 时尚。这种毒性随着时间的推移而发展，甚至在 血红蛋白被去除。所测试的血红蛋白溶液都没有 似乎对小鼠神经胶质细胞有毒。 目前的提案将解决培养物中血红蛋白介导的损伤 大鼠小脑神经元、皮质神经元、纯星形胶质细胞和共 星形胶质细胞和小胶质细胞的培养物。浓度依赖性和 将描述血红蛋白介导的损伤的时间进程。具体的 血浆蛋白将被评估为保护剂，重点是蛋白质 结合并促进血红蛋白或血红素-触珠蛋白的清除 或血红素结合蛋白。其他可能具有治疗潜力的化合物 将评估血红蛋白介导的损伤的治疗。这些化合物 将包括抗氧化剂（如 Trolox、α 生育酚和 21- 氨基类固醇）、螯合剂（例如去铁胺和一种新型去铁胺 衍生物），以及阻止钙进入神经元的药物 （NMDA、红藻氨酸/AMPA、代谢型受体拮抗剂和钙 通道阻断剂）。将进行额外的实验来测试 抗坏血酸和血红蛋白依赖性神经毒性的假设 通过类似的机制介导，抗坏血酸可能会加剧 血红蛋白介导的损伤。最后是热休克的表达 蛋白质 HSP7O 和血红素加氧酶-l 将在神经元中进行检查 星形胶质细胞在血红蛋白和抗坏血酸依赖性过程中 受伤。这些被认为具有保护作用的蛋白质可能会被诱导 不同细胞中的情况不同，部分解释了差异 神经元和星形胶质细胞对血红蛋白的敏感性。