title: Quercetin protects rat dorsal root ganglion neurons against high glucose-induced injury in vitro through Nrf-2/HO-1 activation and NF-κB inhibition.
abstract: OBJECTIVE
  To examine the effects of quercetin, a natural antioxidant, on high glucose (HG)-induced apoptosis of cultured dorsal root ganglion (DRG) neurons of rats.
  
  
  METHODS
  DRG neurons exposed to HG (45 mmol/L) for 24 h were employed as an in vitro model of diabetic neuropathy. Cell viability, reactive oxygen species (ROS) level and apoptosis were determined. The expression of NF-кB, IкBα, phosphorylated IкBα and Nrf2 was examined using RT PCR and Western blot assay. The expression of hemeoxygenase-1 (HO-1), IL-6, TNF-α, iNOS, COX-2, and caspase-3 were also examined.
  
  
  RESULTS
  HG treatment markedly increased DRG neuron apoptosis via increasing intracellular ROS level and activating the NF-κB signaling pathway. Co-treatment with quercetin (2.5, 5, and 10 mmol/L) dose-dependently decreased HG-induced caspase-3 activation and apoptosis. Quercetin could directly scavenge ROS and significantly increased the expression of Nrf-2 and HO-1 in DRG neurons. Quercetin also dose-dependently inhibited the NF-κB signaling pathway and suppressed the expression of iNOS, COX-2, and proinflammatory cytokines IL-6 and TNF-α.
  
  
  CONCLUSIONS
  Quercetin protects rat DRG neurons against HG-induced injury in vitro through Nrf-2/HO-1 activation and NF-κB inhibition, thus may be beneficial for the treatment of diabetic neuropathy.
authors.affiliation: Department of Traditional Chinese Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Shi
authors.forename: Xiao-chun
authors.initials: XC
authors.lastname: Liang
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Qun-li
authors.initials: QL
authors.lastname: Wu
authors.forename: Ling
authors.initials: L
authors.lastname: Qu
authors.forename: Qing
authors.initials: Q
authors.lastname: Sun
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D005260:Female; D005727:Ganglia, Spinal / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D005947:Glucose / Q000633:toxicity*; D006419:Heme Oxygenase (Decyclizing) / Q000096:biosynthesis*; D051267:NF-E2-Related Factor 2 / Q000096:biosynthesis*; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D018696:Neuroprotective Agents / Q000494:pharmacology; D011247:Pregnancy; D011794:Quercetin / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism
chemical_list: D051267:NF-E2-Related Factor 2; D016328:NF-kappa B; D018696:Neuroprotective Agents; C495637:Nfe2l2 protein, rat; D017382:Reactive Oxygen Species; D011794:Quercetin; D006419:Heme Oxygenase (Decyclizing); C491523:Hmox1 protein, rat; D005947:Glucose