Hald Andreas, Nedergaard Signe, Hansen Rikke R, Ding Ming, Heegaard Anne-Marie
Department of Pharmacology and Pharmacotherapy, Faculty of Pharmaceutical Sciences, Copenhagen University, Universitetsparken 2, 2100 Copenhagen, Denmark.
Eur J Pain. 2009 Feb;13(2):138-45. doi: 10.1016/j.ejpain.2008.03.014. Epub 2008 May 21.
Activation of spinal cord microglia and astrocytes is a common phenomenon in nerve injury pain models and is thought to exacerbate pain perception. Following a nerve injury, a transient increase in the presence of microglia takes place while the increased numbers of astrocytes stay elevated for an extended period of time. It has been proposed that activated microglia are crucial for the development of neuropathic pain and that they lead to activation of astrocytes which then play a role in maintaining the long term pathological pain sensation. In the present report, we examined the time course of spinal cord glial activation in three different murine pain models to investigate if microglial activation is a general prerequisite for astrocyte activation in pain models. We found that two different types of cancer induced pain resulted in severe spinal astrogliosis without activation of microglia. In contrast, sciatic nerve injury led to a transient activation of microglia and sustained astrogliosis. These results show that development of hypersensitivity and astrocyte activation in pain models can take place independent of microglial activation.
脊髓小胶质细胞和星形胶质细胞的激活是神经损伤疼痛模型中的常见现象，并且被认为会加剧疼痛感知。神经损伤后，小胶质细胞数量会短暂增加，而星形胶质细胞数量的增加则会在较长时间内持续升高。有人提出，激活的小胶质细胞对于神经性疼痛的发展至关重要，并且它们会导致星形胶质细胞的激活，而星形胶质细胞随后在维持长期病理性疼痛感觉中发挥作用。在本报告中，我们研究了三种不同小鼠疼痛模型中脊髓胶质细胞激活的时间进程，以调查小胶质细胞激活是否是疼痛模型中星形胶质细胞激活的一般先决条件。我们发现，两种不同类型的癌症诱导性疼痛导致严重的脊髓星形胶质细胞增生，而小胶质细胞未被激活。相比之下，坐骨神经损伤导致小胶质细胞短暂激活和持续性星形胶质细胞增生。这些结果表明，疼痛模型中过敏反应的发展和星形胶质细胞的激活可以独立于小胶质细胞激活而发生。
