Differential activation of spinal cord glial cells in murine models of neuropathic and cancer pain.
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.
Hald
Andreas
A
Department of Pharmacology and Pharmacotherapy, Faculty of Pharmaceutical Sciences, Copenhagen University, Universitetsparken 2, 2100 Copenhagen, Denmark.
Nedergaard
Signe
S
Hansen
Rikke R
RR
Ding
Ming
M
Heegaard
Anne-Marie
AM
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001859:Bone Neoplasms / Q000150:complications / Q000473:pathology; D002460:Cell Line; D005904:Glial Fibrillary Acidic Protein / Q000096:biosynthesis / Q000235:genetics; D005911:Gliosis / Q000473:pathology; D007150:Immunohistochemistry; D051379:Mice; D008809:Mice, Inbred C3H; D009369:Neoplasms / Q000150:complications*; D009457:Neuroglia / Q000473:pathology*; D010146:Pain / Q000209:etiology* / Q000473:pathology*; D010147:Pain Measurement; D010523:Peripheral Nervous System Diseases / Q000150:complications* / Q000473:pathology*; D010524:Peripheral Nervous System Neoplasms / Q000150:complications / Q000473:pathology; D010812:Physical Stimulation; D013116:Spinal Cord / Q000473:pathology*; D013373:Substance P / Q000378:metabolism; D014057:Tomography, X-Ray Computed
D005904:Glial Fibrillary Acidic Protein; D013373:Substance P