title: Neuroprotective effect of epigallocatechin-3-gallate against N-methyl-D-aspartate-induced excitotoxicity in the adult rat retina.
abstract: OBJECTIVE
  Epigallocatechin-3-gallate (EGCG), the major polyphenol of green tea, has been suggested to reduce glutamate excitotoxicity. We therefore investigated the potentially protective effects of EGCG against N-methyl-d-aspartate (NMDA)-induced excitotoxicity in the retina.
  
  
  METHODS
  Female Wistar rats (n = 171) were divided into a normal control group (n = 9); saline control group with intravitreal saline injections (n = 54); NMDA control group with an intravitreal NMDA injection and intraperitoneal saline injections (n = 54); and NMDA study group (n = 54) receiving an intravitreal NMDA injection plus intraperitoneal EGCG (25 mg/kg) injections. Starting at 2 days prior to the intravitreal NMDA injection, the intraperitoneal injections were performed daily for the whole study period. At 12 hr, 1, 2, 3 days, 1 and 2 weeks after the intravitreal NMDA injection, the animals were killed. We counted the neurons in the retinal ganglion cell layer (GCL) on histological sections, measured the thickness of Thy-1 immunoreactivity and assessed the expression of Thy-1 mRNA by real-time polymerase chain reaction.
  
  
  RESULTS
  At all time-points, GCL cell density, thickness of Thy-1 immunoreactivity and expression of Thy-1 mRNA were significantly (all p < 0.05) lower in the NMDA control group than in the NMDA study group, in which the parameters were significantly (all p < 0.05) lower than in the saline control group and the normal control group. In both groups with an intravitreal NMDA injection, GCL cell density, thickness of Thy-1 immunoreactivity and expression of Thy-1 mRNA decreased significantly with increasing follow-up time.
  
  
  CONCLUSIONS
  Intraperitoneal application of EGCG resulted in a significantly less marked NMDA-associated loss of retinal ganglion cells.
authors.affiliation: Beijing Ophthalmology and Visual Sciences Key Laboratory, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
authors.forename: Fei
authors.initials: F
authors.lastname: Chen
authors.forename: Libin
authors.initials: L
authors.lastname: Jiang
authors.forename: Ceying
authors.initials: C
authors.lastname: Shen
authors.forename: Hongfei
authors.initials: H
authors.lastname: Wan
authors.forename: Liang
authors.initials: L
authors.lastname: Xu
authors.forename: Ningli
authors.initials: N
authors.lastname: Wang
authors.forename: Jost B
authors.initials: JB
authors.lastname: Jonas
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D002452:Cell Count; D002470:Cell Survival / Q000187:drug effects; D018690:Excitatory Amino Acid Agonists / Q000633:toxicity*; D005260:Female; D007274:Injections, Intraperitoneal; D016202:N-Methylaspartate / Q000633:toxicity*; D018696:Neuroprotective Agents / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012162:Retinal Degeneration / Q000139:chemically induced / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D012165:Retinal Ganglion Cells / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D018800:Thy-1 Antigens / Q000235:genetics / Q000378:metabolism
chemical_list: D018690:Excitatory Amino Acid Agonists; D018696:Neuroprotective Agents; D012333:RNA, Messenger; D018800:Thy-1 Antigens; D016202:N-Methylaspartate; D002392:Catechin; C045651:epigallocatechin gallate