Ligustilide ameliorates neuroinflammation and brain injury in focal cerebral ischemia/reperfusion rats: involvement of inhibition of TLR4/peroxiredoxin 6 signaling.

Abstract

Blocking TLR4/peroxiredoxin (Prx6) signaling is proposed to be a novel therapeutic strategy for ischemic stroke because extracellular Prx6 released from ischemic cells may act as an endogenous ligand for TLR4 and initiate destructive immune responses in ischemic brain. Our previous studies showed that ligustilide (LIG) exerted antineuroinflammatory and neuroprotective effects against ischemic insult, but the underlying mechanisms remain unclear. This study investigated whether the TLR4/Prx6 pathway is involved in the protective effect of LIG against postischemic neuroinflammation and brain injury induced by transient middle cerebral artery occlusion (MCAO) in rats. Intraperitoneal LIG administration (20 and 40 mg/kg/day) at reperfusion onset after MCAO resulted in a reduction of brain infarct size and improved neurological outcome over 72 h. LIG-induced neuroprotection was accompanied by improvement of neuropathological alterations, including neuron loss, astrocyte and microglia/macrophage activation, neutrophil and T-lymphocyte invasion, and regulation of inflammatory mediators expression. Moreover, LIG significantly inhibited the expression and extracellular release of Prx6 and activation of TLR4 signaling, reflected by decreased TLR4 expression, extracellular signal-regulated kinase 1/2 phosphorylation, and transcriptional activity of NF-κB and signal transducer and activator of transcription 3 in the ischemic brain. Our results demonstrate that LIG may provide an early and direct neuroprotection by inhibiting TLR4/Prx6 signaling and subsequent immunity and neuroinflammation after cerebral ischemia. These findings support the translational potential of blocking TLR4/Prx6 signaling for the treatment of ischemic stroke.

• Authors: Xi Kuang, Liang-Fen Wang, Lu Yu, Yong-Jie Li, Yan-Nan Wang, Qian He, Chu Chen, Jun-Rong Du
• Journal: Free radical biology & medicine (Free Radic Biol Med) Vol. 71 Pg. 165-175 (Jun 2014) ISSN: 1873-4596 [Electronic] United States
• PMID: 24681253 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: Copyright © 2014 Elsevier Inc. All rights reserved.

Chemical References

• Anti-Inflammatory Agents, Non-Steroidal
• NF-kappa B
• STAT3 Transcription Factor
• Stat3 protein, rat
• Tlr4 protein, rat
• Toll-Like Receptor 4
• ligustilide
• Peroxiredoxin VI
• Prdx6 protein, rat
• Mitogen-Activated Protein Kinase 1
• Mitogen-Activated Protein Kinase 3
• 4-Butyrolactone

Topics

• 4-Butyrolactone (analogs & derivatives, pharmacology)
• Animals
• Anti-Inflammatory Agents, Non-Steroidal (pharmacology)
• Astrocytes (drug effects, immunology, pathology)
• Brain Ischemia (drug therapy, genetics, immunology, pathology)
• Cell Movement (drug effects)
• Gene Expression Regulation
• Inflammation (drug therapy, genetics, immunology, pathology)
• Injections, Intraperitoneal
• Macrophage Activation (drug effects)
• Male
• Microglia (drug effects, immunology, pathology)
• Mitogen-Activated Protein Kinase 1 (genetics, metabolism)
• Mitogen-Activated Protein Kinase 3 (genetics, metabolism)
• NF-kappa B (genetics, metabolism)
• Neurons (drug effects, immunology, pathology)
• Oxidative Stress
• Peroxiredoxin VI (antagonists & inhibitors, genetics, immunology)
• Rats
• Rats, Sprague-Dawley
• Reperfusion Injury (drug therapy, genetics, immunology, pathology)
• STAT3 Transcription Factor (genetics, metabolism)
• Signal Transduction
• T-Lymphocytes (drug effects, immunology, pathology)
• Toll-Like Receptor 4 (antagonists & inhibitors, genetics, immunology)