title: Toll-like receptor 3 agonist Poly I:C protects against simulated cerebral ischemia in vitro and in vivo.
abstract: OBJECTIVE
  To examine the neuroprotective effects of the Toll-like receptor 3 (TLR3) agonist Poly I:C in acute ischemic models in vitro and in vivo.
  
  
  METHODS
  Primary astrocyte cultures subjected to oxygen-glucose deprivation (OGD) were used as an in vitro simulated ischemic model. Poly I:C was administrated 2 h before OGD. Cell toxicity was measured using MTT assay and LDH leakage assay. The levels of TNFα, IL-6 and interferon-β (IFNβ) in the media were measured using ELISA. Toll/interleukin receptor domain-containing adaptor-inducing IFNβ (TRIF) protein levels were detected using Western blot analysis. A mouse middle cerebral artery occlusion (MCAO) model was u sed for in vivo study. The animals were administered Poly I:C (0.3 mg/kg, im) 2 h before MCAO, and examined with neurological deficit scoring and TTC staining. The levels of TNFα and IL-6 in ischemic brain were measured using ELISA.
  
  
  RESULTS
  Pretreatment with Poly I:C (10 and 20 μg/mL) markedly attenuated OGD-induced astrocyte injury, and significantly raised the cell viability and reduced the LDH leakage. Poly I:C significantly upregulated TRIF expression accompanied by increased downstream IFNβ production. Moreover, Poly I:C significantly suppressed the pro-inflammatory cytokines TNFα and IL-6 production. In mice subjected to MCAO, administration of Poly I:C significantly attenuated the neurological deficits, reduced infarction volume, and suppressed the increased levels of TNFα and IL-6 in the ischemic striatum and cortex.
  
  
  CONCLUSIONS
  Poly I:C pretreatment exerts neuroprotective and anti-inflammatory effects in the simulated cerebral ischemia models, and the neuroprotection is at least in part due to the activation of the TLR3-TRIF pathway.
authors.affiliation: Department of Pharmacology, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Lin-na
authors.initials: LN
authors.lastname: Pan
authors.forename: Wei
authors.initials: W
authors.lastname: Zhu
authors.forename: Cai
authors.initials: C
authors.lastname: Li
authors.forename: Xu-lin
authors.initials: XL
authors.lastname: Xu
authors.forename: Lian-jun
authors.initials: LJ
authors.lastname: Guo
authors.forename: Qing
authors.initials: Q
authors.lastname: Lu
mesh_terms: D000818:Animals; D001253:Astrocytes / Q000187:drug effects* / Q000378:metabolism; D015153:Blotting, Western; D018929:Cell Culture Techniques; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D003470:Culture Media; D004195:Disease Models, Animal; D004797:Enzyme-Linked Immunosorbent Assay; D005947:Glucose / Q000378:metabolism; D002546:Ischemic Attack, Transient / Q000378:metabolism / Q000517:prevention & control*; D051379:Mice; D018696:Neuroprotective Agents / Q000494:pharmacology / Q000627:therapeutic use*; D010100:Oxygen / Q000378:metabolism; D011070:Poly I-C / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D051196:Toll-Like Receptor 3 / Q000819:agonists*
chemical_list: D003470:Culture Media; D018696:Neuroprotective Agents; D051196:Toll-Like Receptor 3; D005947:Glucose; D011070:Poly I-C; D010100:Oxygen