title: The possible involvement of JNK activation in the spinal dorsal horn in bortezomib-induced allodynia: the role of TNF-α and IL-1β.
abstract: OBJECTIVE
  Bortezomib (BTZ), a widely used chemotherapeutic drug, is closely associated with the development of painful peripheral neuropathy, but the mechanism underlying the induction of this disorder by BTZ remains largely unclear. To examine this association, we have evaluated the activation of mitogen-activated protein kinase (MAPK) family members in the spinal dorsal horn and the role of tumor necrosis factor alpha (TNF-α) and interleukin-1 beta (IL-1β) in BTZ-induced allodynia in rats.
  
  
  METHODS
  Male Sprague-Dawley rats were used as the model animals. The paw withdrawal test, in which mechanical stimuli (von Frey hairs) is applied to the plantar surface of the hindpaw, was used to determine any changes in the paw withdrawal threshold of the treated rats. A PE-10 catheter was placed intrathecally to deliver TNF-α neutralizing antibody, IL-1 receptor antagonist (IL-1ra) or the c-Jun N-terminal kinase (JNK) inhibitor SP600125. The mRNA levels of various cytokines were measured by real-time quantitative PCR. The expression of TNF-α, IL-1β and mitogen-activated protein kinase (MAPK) family members in the spinal dorsal horn was measured by western blot analysis and immunohistochemistry. All data were expressed as the mean ± standard error of the mean and analyzed using the SPSS version 13.0 software program.
  
  
  RESULTS
  The BTZ treatment induced an upsurge in the mRNA and protein levels of TNF-α in the neurons and IL-1β in the astrocytes in the spinal dorsal horn. It also significantly upregulated the phosphorylation of JNK but not of extracellular signal-regulated kinases (ERK) and p38-MAPK in astrocytes of the spinal dorsal horn. Inhibition of TNF-α or IL-1β ameliorated JNK activation and mechanical allodynia induced by BTZ. Co-administration of thalidomide (TNF-α synthesis inhibitor) and IL-1ra prevented BTZ-induced mechanical allodynia.
  
  
  CONCLUSIONS
  Our results suggest that the TNF-α or IL-1β/JNK pathway in the spinal dorsal horn may play a critical role in the development of painful peripheral neuropathy induced by BTZ.
authors.affiliation: Department of General Internal Medicine, The First Affiliated Hospital of Sun Yat-sen University, Sun Yet-Sen University, 58 Zhongshan Rd. 2, Guangzhou, 510080, China.
authors.forename: Zhen-Yu
authors.initials: ZY
authors.lastname: Li
authors.affiliation: Department of Physiology and Pain Research Center, Zhongshan Medical School, Sun Yet-Sen University, 74 Zhongshan Rd. 2, Guangzhou, 510080, China.
authors.forename: Yuan-Pei
authors.initials: YP
authors.lastname: Zhang
authors.affiliation: Department of Physiology and Pain Research Center, Zhongshan Medical School, Sun Yet-Sen University, 74 Zhongshan Rd. 2, Guangzhou, 510080, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Physiology and Pain Research Center, Zhongshan Medical School, Sun Yet-Sen University, 74 Zhongshan Rd. 2, Guangzhou, 510080, China.
authors.forename: Su-Bo
authors.initials: SB
authors.lastname: Zhang
authors.affiliation: Department of Physiology and Pain Research Center, Zhongshan Medical School, Sun Yet-Sen University, 74 Zhongshan Rd. 2, Guangzhou, 510080, China.
authors.forename: Dai
authors.initials: D
authors.lastname: Li
authors.affiliation: Department of Physiology and Pain Research Center, Zhongshan Medical School, Sun Yet-Sen University, 74 Zhongshan Rd. 2, Guangzhou, 510080, China.
authors.forename: Zhen-Zhen
authors.initials: ZZ
authors.lastname: Huang
authors.affiliation: Department of Physiology and Pain Research Center, Zhongshan Medical School, Sun Yet-Sen University, 74 Zhongshan Rd. 2, Guangzhou, 510080, China. xinwj@mail.sysu.edu.cn.
authors.forename: Wen-Jun
authors.initials: WJ
authors.lastname: Xin
mesh_terms: D000818:Animals; D000069286:Bortezomib / Q000633:toxicity*; D016207:Cytokines / Q000235:genetics; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D006930:Hyperalgesia / Q000139:chemically induced*; D053583:Interleukin-1beta / Q000378:metabolism; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D008297:Male; D009437:Neuralgia / Q000139:chemically induced*; D012333:RNA, Messenger / Q000235:genetics; D051381:Rats; D017207:Rats, Sprague-Dawley; D066148:Spinal Cord Dorsal Horn; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D016207:Cytokines; D053583:Interleukin-1beta; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D000069286:Bortezomib; D048049:Extracellular Signal-Regulated MAP Kinases; D048031:JNK Mitogen-Activated Protein Kinases
keywords: Allodynia; Bortezomib; IL-1β; TNF-α; c-Jun N-terminal kinase