Inhibitory effect on cerebral inflammatory agents that accompany traumatic brain injury in a rat model: a potential neuroprotective mechanism of recombinant human erythropoietin (rhEPO).
Erythropoietin (EPO) has recently been shown to have a neuroprotective effect in animal models of traumatic brain injury (TBI). However, the precise mechanisms remain unclear. Cerebral inflammation plays an important role in the pathogenesis of secondary brain injury after TBI. We, therefore, tried to analyze how recombinant human erythropoietin (rhEPO) might effect the inflammation-related factors common to TBI: nuclear factor kappa B (NF-kappaB), interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and intercellular adhesion molecule-1 (ICAM-1) in a rat TBI model. Male rats were given 0 or 5000 units/kg injections of rhEPO 1h post-injury and on days 1, 2 and 3 after surgery. Brain samples were extracted at 3 days after trauma. We measured NF-kappaB by electrophoretic mobility shift assay (EMSA); IL-1beta, TNF-alpha and IL-6 by enzyme-linked immunosorbent assay (ELISA); ICAM-1 by immunohistochemistry; brain edema by wet/dry method; blood-brain barrier (BBB) permeability by Evans blue extravasation and cortical apoptosis by terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method. We found that NF-kappaB, pro-inflammatory cytokines and ICAM-1 were increased in all injured animals. In animals given rhEPO post-TBI, NF-kappaB, IL-1beta, TNF-alpha and ICAM-1 were decreased in comparison to vehicle-treated animals. Measures of IL-6 showed no change after rhEPO treatment. Administration of rhEPO reduced brain edema, BBB permeability and apoptotic cells in the injured brain. In conclusion, post-TBI rhEPO administration may attenuate inflammatory response in the injured rat brain, and this may be one mechanism by which rhEPO improves outcome following TBI.
Chen
Gang
G
Department of Neurosurgery, Jinling Hospital, School of Medicine, Nanjing University, 305 East Zhongshan Road, Nanjing 210002, Jiangsu Province, China. nju_neurosurgery@163.com
Shi
Ji Xin
JX
Hang
Chun Hua
CH
Xie
Weiying
W
Liu
Jian
J
Liu
Xiaoming
X
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology / Q000627:therapeutic use; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000378:metabolism; D001929:Brain Edema / Q000188:drug therapy / Q000209:etiology / Q000503:physiopathology; D001930:Brain Injuries / Q000150:complications / Q000188:drug therapy* / Q000503:physiopathology; D002540:Cerebral Cortex / Q000187:drug effects* / Q000378:metabolism / Q000503:physiopathology; D019610:Cytoprotection / Q000187:drug effects / Q000502:physiology; D004195:Disease Models, Animal; D004660:Encephalitis / Q000188:drug therapy* / Q000209:etiology / Q000503:physiopathology; D004921:Erythropoietin / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D018836:Inflammation Mediators / Q000037:antagonists & inhibitors* / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000187:drug effects / Q000378:metabolism; D053583:Interleukin-1beta / Q000037:antagonists & inhibitors / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D008297:Male; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D011994:Recombinant Proteins / Q000494:pharmacology / Q000627:therapeutic use; D016896:Treatment Outcome; D014409:Tumor Necrosis Factor-alpha / Q000037:antagonists & inhibitors / Q000378:metabolism; D000093242:Interleukin-6 Inhibitors