title: Investigation of Glutathione S-Transferase Isoenzyme Protein Expression in Patients With Pterygium.
abstract: OBJECTIVE
  We investigated glutathione S-transferase (GST) enzymes in terms of their potential effects on the pathogenesis of pterygium.
  
  
  METHODS
  Twenty-six pterygium specimens and 15 normal conjunctival specimens of 15 control subjects were investigated. Expressions of GST (alpha, mu, pi, and theta) enzymes were assessed by immunohistochemical staining. A brown color in the cytoplasm and/or nuclei of epithelial cells was evaluated as positive staining for GST enzymes. For each antibody, the intensity of the reaction [negative (-), weak (1+), moderate (2+), or strong (3+)] was determined to describe the immunoreactions.
  
  
  RESULTS
  The median age was 52 years in the both groups. There was no significant difference between the groups in terms of age, sex, and intraocular pressure measurements (P > 0.05 for all). Of the 26 pterygium specimens, 15 (57.7%) (8 weak, 4 moderate, and 3 strong staining) were identified with GST pi-1 (GSTP1) expression and 20 (76.9%) (12 weak, 7 moderate, and 1 strong staining) with GST theta-1 (GSTT1) expression. Of the 15 control specimens, 4 (26.7%) (4 weak staining) were identified with the GSTP1 expression, and 1 (6.7%) with GSTT1 expression. GSTP1 and GSTT1 expressions were significantly higher in the pterygium specimens than in the controls (P = 0.043, P < 0.001; respectively). None of tissue specimens had positive staining for GST mu-1 or GST alpha-1 in both groups (both; P = 1.00).
  
  
  CONCLUSIONS
  The significant increase of GSTP1 and GSTT1 expressions in pterygium may be because of the increased activation of GST in response to excessive free radical formation from ultraviolet exposure to maintain antioxidant capacity in pterygium.
authors.affiliation: *Department of Ophthalmology, Istanbul Medeniyet University School of Medicine, Goztepe, Istanbul, Turkey; †Cornea Deparment, Wills Eye Hospital, Sidney Kimmel Medical College of Thomas Jefferson University, Philadelphia, PA, USA; ‡Department of Ophthalmology, Ipekyolu Government Hospital, Van, Turkey; §Department of Biology, Kırıkkale University School of Medicine, Kirikkale, Turkey; and ¶Department of Pathology, Kecioren Research and Training Hospital, Ankara, Turkey.
authors.forename: Remzi
authors.initials: R
authors.lastname: Karadag
authors.forename: Nurettin
authors.initials: N
authors.lastname: Bayram
authors.forename: Serpil
authors.initials: S
authors.lastname: Oguztuzun
authors.forename: Busra
authors.initials: B
authors.lastname: Bozer
authors.forename: Huseyin
authors.initials: H
authors.lastname: Bayramlar
authors.forename: Gulcin Guler
authors.initials: GG
authors.lastname: Simsek
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Rapuano
mesh_terms: D000328:Adult; D000368:Aged; D003228:Conjunctiva / Q000201:enzymology; D005260:Female; D051549:Glutathione S-Transferase pi / Q000378:metabolism*; D005982:Glutathione Transferase / Q000378:metabolism*; D006801:Humans; D007124:Immunoenzyme Techniques; D007527:Isoenzymes / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D011625:Pterygium / Q000201:enzymology* / Q000601:surgery
chemical_list: D051549:Glutathione S-Transferase pi; D005982:Glutathione Transferase; D007527:Isoenzymes; C413545:glutathione S-transferase T1; C496556:GSTP1 protein, human; C119995:glutathione S-transferase alpha