title: Equol protects PC12 neuronal cells against hypoxia/reoxygenation injury in vitro by reducing reactive oxygen species production.
abstract: OBJECTIVE
  Both of gp91(phox) (an isoform of nicotinamide adenine dinucleotide phosphate-reduced oxidases) and Src (a non-receptor protein tyrosine kinase) play a prominent role in mediating hypoxia/reoxygenation injury of neurons. The present study was designed to investigate the neuroprotective effect of equol, a predominant active metabolite of daidzein, against hypoxia/reoxygenation injury in rat pheochromocytoma cell line (PC12) and explore the underlying mechanisms.
  
  
  METHODS
  PC12 cells exposed to hypoxia/reoxygenation injury were examined for reactive oxygen species (ROS) using dihydroethidium and 2', 7'-dichlorofluorescein diacetate and analyzed for changes in lactate dehydrogenase (LDH) activity and malondialdehyde (MDA) content. The expression levels of gp91(phox) and phosphorylated Src-Tyr416 (p-Src) were measured using Western blotting.
  
  
  RESULTS
  Equol dose-dependently restored the cell viability and decreased LDH activity and MDA content in culture medium of PC12 cells exposed to hypoxia/reoxygenation. Pretreatment of the cells with 10(-5) and 10(-6) mol/L equol inhibited hypoxia/reoxygenation-induced increase of ROS. PC12 cells treated with equol prior to hypoxia/reoxygenation injury showed significant enhancement of the protein levels of gp91(phox) and p-Src.
  
  
  CONCLUSIONS
  Equol confers neuroprotection against hypoxia/reoxygenation injury in PC12 cells by inhibiting the generation of ROS very likely as a result of down-regulation of gp91(phox) and inhibition of Src phosphorylation.
authors.affiliation: Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Xi'an Jiaotong University Health Science Center, Xi'an 710061, China.E-mail: marine_wei@163.com.
authors.forename: Wei
authors.initials: W
authors.lastname: Yu
authors.forename: Xiuling
authors.initials: X
authors.lastname: Deng
authors.forename: Zhen
authors.initials: Z
authors.lastname: Ma
authors.forename: Yan
authors.initials: Y
authors.lastname: Wang
mesh_terms: D000818:Animals; D015687:Cell Hypoxia; D002470:Cell Survival; D015536:Down-Regulation; D060754:Equol / Q000494:pharmacology*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008315:Malondialdehyde / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000378:metabolism; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D018696:Neuroprotective Agents / Q000494:pharmacology*; D016716:PC12 Cells; D010766:Phosphorylation; D051381:Rats; D017382:Reactive Oxygen Species / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism
chemical_list: D008562:Membrane Glycoproteins; D018696:Neuroprotective Agents; D017382:Reactive Oxygen Species; D008315:Malondialdehyde; D060754:Equol; D007770:L-Lactate Dehydrogenase; C500593:Cybb protein, rat; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; D019061:src-Family Kinases