title: Ferulic acid, but not tetramethylpyrazine, significantly attenuates retinal ischemia/reperfusion-induced alterations by acting as a hydroxyl radical scavenger.
abstract: OBJECTIVE
  Ischemia plays an important role in glaucomatous optic neuropathy and retinal vascular occlusive disorders, which renders investigation vital.
  
  
  METHODS
  Retinal ischemia was induced by raising intraocular pressure to 120 mmHg. Its mechanism and management was evaluated by measuring (*)OH levels, electroretinogram (ERG) b-wave amplitudes, immunohisto-chemistry, and reverse transcriptase polymerase chain reaction.
  
  
  RESULTS
  Ischemia for 45, 60, and 75 min caused significant and time-dependent increased (*)OH levels, which might contribute to retinal ischemic injures. Specifically, 60 min of ischemia plus reperfusion, causing moderate oxidative stress, resulted in retinal changes that were characterized by decreased ERG b-wave amplitudes, loss of choline acetyltransferase immunolabeled amacrine cell bodies/neuronal processes, downregulated Thy-1 m-RNA levels (indexing retinal ganglion cells; RGCs), and reduced thickness of the Thy-1 immunolabeled RGC and inner plexiform layers. Of clinical importance, this is the first study to show that ischemic detrimental effects are significantly blunted when 0.5 nmol of ferulic acid, one active ingredient of Ligusticum walliichi (Chuanxiong), was applied 24 h before retinal ischemia. Further, but not to a significant level, 0.5 nmole of tetramethylpyrazine, another Chuanxiong-active component, showed such an ameliorating trend. Moreover, the 60-min ischemia-induced significant increase in (*)OH production was significantly attenuated by FA.
  
  
  CONCLUSIONS
  FA is able to protect against retinal ischemia and possibly glaucoma by, at least in part, acting as a (*)OH scavenger.
authors.affiliation: Department of Ophthalmology, Veterans General Hospital, Taipei, Taiwan, ROC. hsiao-ming.chao@vghtpe.gov.tw
authors.forename: Hsiao-Ming
authors.initials: HM
authors.lastname: Chao
authors.forename: De-Ean
authors.initials: DE
authors.lastname: Lin
authors.forename: Ying
authors.initials: Y
authors.lastname: Chang
authors.forename: Weng-Ming
authors.initials: WM
authors.lastname: Hsu
authors.forename: Shui-Mei
authors.initials: SM
authors.lastname: Lee
authors.forename: Fenq-Lih
authors.initials: FL
authors.lastname: Lee
authors.forename: Chin-Wen
authors.initials: CW
authors.lastname: Chi
authors.forename: Wynn H T
authors.initials: WH
authors.lastname: Pan
authors.forename: Tsung-Yun
authors.initials: TY
authors.lastname: Liu
authors.forename: Wing-Yiu
authors.initials: WY
authors.lastname: Lui
authors.forename: Low-Tone
authors.initials: LT
authors.lastname: Ho
authors.forename: Cheng-Deng
authors.initials: CD
authors.lastname: Kuo
authors.forename: Chia-Chin
authors.initials: CC
authors.lastname: Chan
authors.forename: Fang-Ping
authors.initials: FP
authors.lastname: Chao
mesh_terms: D000818:Animals; D003373:Coumaric Acids / Q000494:pharmacology* / Q000627:therapeutic use; D004596:Electroretinography; D016166:Free Radical Scavengers / Q000494:pharmacology / Q000627:therapeutic use; D017665:Hydroxyl Radical / Q000378:metabolism; D007150:Immunohistochemistry; D007511:Ischemia / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D018696:Neuroprotective Agents / Q000494:pharmacology* / Q000627:therapeutic use; D011719:Pyrazines / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D017208:Rats, Wistar; D017382:Reactive Oxygen Species / Q000378:metabolism; D015427:Reperfusion Injury / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D012160:Retina / Q000187:drug effects* / Q000378:metabolism; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction
chemical_list: D003373:Coumaric Acids; D016166:Free Radical Scavengers; D018696:Neuroprotective Agents; D011719:Pyrazines; D017382:Reactive Oxygen Species; D017665:Hydroxyl Radical; C004999:ferulic acid; C017953:tetramethylpyrazine