title: Oxidant/antioxidant state in tissue of prymary and recurrent pterygium.
abstract: BACKGROUND
  Pterygium is a disorder of the ocular surface induced by chronic exposure to UV-light. Abundant data is available from patients with primary pterygium, but scarce from those with recurrent pterygium. The present study aimed to explore the oxidant/antioxidant status in tissue of primary and recurrent pterigium in men and women.
  
  
  METHODS
  Pathological tissue samples were taken during surgery on patients with primary and recurrent pterygium. Healthy conjunctive tissue samples were taken during cataract surgery. After homogenization of 77 tissue samples, evaluation was made of thiobarbituric reactive substances (TBARS), nitric oxide (NO), total antioxidant status (TAS) and the activity of the three main antioxidant enzymes: glutathione peroxidase, superoxide dismutase and catalase. Gender differences were evaluated.
  
  
  RESULTS
  Compared to the control group, in the primary pterygium group there was an increase in NO and TAS, and a tendency to a decrease of all antioxidant enzymes, indicating an increase in non-enzymatic antioxidant activity. Compared to the control group, in the recurrent pterygium group there was a significant decrease in the level of TAS and antioxidant enzymes. A high positive correlation was found between most of measured parameters within the control group and the recurrent pterygium group, but not within the primary pterygium group. Compared to men, a significant difference was observed in the elevated NO level and low TAS level of women in the prymary pterygium group.
  
  
  CONCLUSIONS
  The diminished antioxidant defense in the recurrent pterygium group, possibly determined mainly by decreased non-enzymatic activity, supports the idea that oxidative stress plays an important role in the recurrence of this disorder.
authors.affiliation: Section of Postgrade and Investigation, Superior Medicine School, National Polytechnic Institute, Hopelchen Mn316 Lt2, Col, Heroes de Padierna, Del, Tlalpan, México City, DF CP14200, Mexico. kormanovski@yahoo.com.mx.
authors.forename: Alexandre
authors.initials: A
authors.lastname: Kormanovski
authors.forename: Fidelina
authors.initials: F
authors.lastname: Parra
authors.forename: Adriana
authors.initials: A
authors.lastname: Jarillo-Luna
authors.forename: Eleazar
authors.initials: E
authors.lastname: Lara-Padilla
authors.forename: Judith
authors.initials: J
authors.lastname: Pacheco-Yépez
authors.forename: Rafael
authors.initials: R
authors.lastname: Campos-Rodriguez
mesh_terms: D000328:Adult; D000368:Aged; D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D003228:Conjunctiva / Q000378:metabolism; D005260:Female; D005979:Glutathione Peroxidase / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000378:metabolism*; D016877:Oxidants / Q000378:metabolism*; D018384:Oxidative Stress; D011625:Pterygium / Q000378:metabolism*; D012008:Recurrence; D012737:Sex Factors; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism*
chemical_list: D000975:Antioxidants; D016877:Oxidants; D017392:Thiobarbituric Acid Reactive Substances; D009569:Nitric Oxide; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase