title: Dynamic distributions of tumor necrosis factor-alpha and its receptors in the red nucleus of rats with spared nerve injury.
abstract: Previous studies have demonstrated that tumor necrosis factor-alpha (TNF-α) in the red nucleus (RN) plays a facilitated role in the development of neuropathic pain, and its effect is transmitted through TNF-α receptor (TNFR) subtypes 1 and 2. Here, the dynamic distributions of TNF-α and TNFRs in the RN of rats with spared nerve injury (SNI) were investigated. Western blot analysis and immunofluorescence staining indicated that TNF-α was hardly expressed in the RN of normal rats but significantly increased at 1 week and peaked at 2 weeks after SNI. Neurons and oligodendrocytes showed TNF-α expression at both 1 week and 2 weeks after SNI, while astrocytes and microglia produced TNF-α later than neurons and oligodendrocytes starting at 2 weeks after SNI. TNFR1 was constitutively expressed in the RN of normal rats and significantly enhanced at 2 weeks but not 1 week after SNI; it was mainly localized in neurons, oligodendrocytes and microglia. Astrocytes were not immunopositive for TNFR1 under normal conditions and at 1 week after injury, but small amounts of astrocytes showed TNFR1 expression at 2 weeks after SNI. A low level of TNFR2 was expressed in the RN of normal rats, but it was significantly increased at 1 week and 2 weeks after SNI and localized in neurons and all three types of glia. These findings suggest that neurons and three types of glia in the RN all contribute to TNF-α production and participate in the initiation and/or maintenance of neuropathic pain induced by SNI. TNF-α exerts its effects in different types of cells maybe through different receptors, TNFR1 and/or TNFR2, in the different stages of neuropathic pain.
authors.affiliation: Departments of Pathogenic Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.affiliation: Departments of Pathogenic Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China.
authors.forename: Cui-Ping
authors.initials: CP
authors.lastname: Ding
authors.affiliation: Departments of Pathogenic Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Yu
authors.affiliation: Department of Laboratory Medicine, The First Affiliated Hospital, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China.
authors.forename: Xiao-Yan
authors.initials: XY
authors.lastname: Zeng
authors.affiliation: Department of Pathology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China.
authors.forename: Shui-Ping
authors.initials: SP
authors.lastname: Han
authors.affiliation: Departments of Pathogenic Biology and Immunology, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China.
authors.forename: Jun-Yang
authors.initials: JY
authors.lastname: Wang
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000378:metabolism; D004195:Disease Models, Animal; D006930:Hyperalgesia / Q000378:metabolism; D008297:Male; D017628:Microglia / Q000378:metabolism; D009437:Neuralgia / Q000378:metabolism*; D009474:Neurons / Q000378:metabolism; D009836:Oligodendroglia / Q000378:metabolism; D010147:Pain Measurement; D017288:Pain Threshold; D051381:Rats; D017207:Rats, Sprague-Dawley; D047888:Receptors, Tumor Necrosis Factor, Type I / Q000378:metabolism*; D047889:Receptors, Tumor Necrosis Factor, Type II / Q000378:metabolism*; D012012:Red Nucleus / Q000378:metabolism*; D020426:Sciatic Neuropathy; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*
chemical_list: D047888:Receptors, Tumor Necrosis Factor, Type I; D047889:Receptors, Tumor Necrosis Factor, Type II; D014409:Tumor Necrosis Factor-alpha
keywords: neuropathic pain; red nucleus; spared nerve injury; tumor necrosis factor receptor; tumor necrosis factor-alpha