Baicalin inhibits TLR2/4 signaling pathway in rat brain following permanent cerebral ischemia

Inflammation. 2011 Oct;34(5):463-70. doi: 10.1007/s10753-010-9254-8.

Abstract

Recent work from our laboratory demonstrated that baicalin attenuates inflammatory reaction and cerebral ischemia injury in rats. Toll-like receptor 2 and 4 (TLR2/4) and the downstream nuclear factor-kappa B (NF-κB) signaling pathway, which mediate the inflammatory reaction, are involved in the pathophysiological processes of cerebral ischemia. In this study, we investigated whether baicalin inhibits TLR2/4 signaling pathway in a rat model of permanent focal cerebral ischemia. Adult Sprague-Dawley rats underwent permanent middle cerebral artery occlusion (MCAO). Baicalin was administered by intraperitoneally injected twice at 2 and 12 h after the onset of ischemia. Cerebral infarct area and infarct volume were measured 24 h after MCAO. Expression of TLR2/4, NF-κB, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) were determined by RT-PCR or western blot. NO and PGE2 production in rat brain were measured 24 h after MCAO. Serum content of tumor necrosis factor-alpha (TNF-α) and interleukin-1β (IL-1β) were detected by ELISA. Baicalin reduced cerebral infarct area and infarct volume. Baicalin reduced the expression of TLR2/4 and NF-κB, decreased the expression and activity of iNOS and COX-2 in rat brain. Baicalin also attenuated the serum content of TNF-α and IL-1β. Our results suggest that baicalin inhibits the TLR2/4 signaling pathway in cerebral ischemia, which may be a mechanism underlying the baicalin's neuroprotection.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology
  • Brain / drug effects*
  • Brain / metabolism*
  • Brain Ischemia / drug therapy*
  • Brain Ischemia / genetics
  • Brain Ischemia / metabolism*
  • Brain Ischemia / pathology
  • Cyclooxygenase 2 / metabolism
  • Disease Models, Animal
  • Flavonoids / pharmacology*
  • Infarction, Middle Cerebral Artery / drug therapy
  • Infarction, Middle Cerebral Artery / genetics
  • Infarction, Middle Cerebral Artery / metabolism
  • Infarction, Middle Cerebral Artery / pathology
  • Interleukin-1beta / blood
  • Male
  • Neuroprotective Agents / pharmacology*
  • Nitric Oxide Synthase Type II / antagonists & inhibitors
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Signal Transduction / drug effects
  • Toll-Like Receptor 2 / antagonists & inhibitors*
  • Toll-Like Receptor 2 / genetics
  • Toll-Like Receptor 4 / antagonists & inhibitors*
  • Toll-Like Receptor 4 / genetics
  • Transcription Factor RelA / metabolism
  • Tumor Necrosis Factor-alpha / blood

Substances

  • Anti-Inflammatory Agents, Non-Steroidal
  • Flavonoids
  • Interleukin-1beta
  • Neuroprotective Agents
  • RNA, Messenger
  • Rela protein, rat
  • Tlr2 protein, rat
  • Tlr4 protein, rat
  • Toll-Like Receptor 2
  • Toll-Like Receptor 4
  • Transcription Factor RelA
  • Tumor Necrosis Factor-alpha
  • baicalin
  • Nitric Oxide Synthase Type II
  • Nos2 protein, rat
  • Cyclooxygenase 2
  • Ptgs2 protein, rat