title: Excessive milk intake as a risk factor, probably associated with oxidative stress, in experimental naphthalene-initiated cataract in rats.
abstract: OBJECTIVE
  To determine whether a diet containing excessive amounts of milk aggravates naphthalene-initiated cataracts in a common animal model of age-related human cataract.
  
  
  METHODS
  Ninety Sprague-Dawley rats were fed a natural diet supplemented with either water (group A), normal amounts of milk (group B), excessive amounts of milk (group C), naphthalene plus water (group D), naphthalene plus normal amounts of milk (group E), naphthalene plus excessive amounts of milk (group F). Cataract development was monitored weekly using a slit lamp and lens gray value analysis. Concentrations of reactive oxygen species (ROS), reduced glutathione (GSH) and malondialdehyde (MDA) in rat lenses were measured to determine the role of oxidative stress in cataract induction.
  
  
  RESULTS
  By week 4, the cortical gray value was significantly higher in group F than that in group D, and the cortical gray value was significantly higher in group D than in group A. However, by week 8, no significant differences were observed among groups C, F, B, E and A. ROS concentrations in lenses of rats of groups C and F were slightly higher than in those of groups B, E and A, but ROS concentrations in group F were significantly higher than in the other groups receiving naphthalene (i.e. groups D and E). GSH concentrations in group F were significantly lower than in the other groups. MDA concentrations in group F were significantly higher than in the other groups receiving naphthalene, indicating increased lipid peroxidation induced by naphthalene plus excessive intake of milk.
  
  
  CONCLUSIONS
  Our results provide quantitative evidence that excessive intake of milk aggravates naphthalene-initiated cataracts, which is probably due to oxidative damage caused by increased ROS.
authors.affiliation: Department of Ophthalmology, Eye Ear Nose and Throat Hospital of Fudan University, Shanghai, PR China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Chen
authors.forename: Yong Xiang
authors.initials: YX
authors.lastname: Jiang
authors.forename: Lu
authors.initials: L
authors.lastname: Yi
authors.forename: Ai Zhu
authors.initials: AZ
authors.lastname: Miu
authors.forename: Shu Jie
authors.initials: SJ
authors.lastname: Zhang
authors.forename: Ji Hong
authors.initials: JH
authors.lastname: Wu
authors.forename: Sheng Hai
authors.initials: SH
authors.lastname: Zhang
mesh_terms: D000818:Animals; D002386:Cataract / Q000139:chemically induced* / Q000378:metabolism / Q000503:physiopathology; D004032:Diet; D004195:Disease Models, Animal; D005260:Female; D005978:Glutathione / Q000378:metabolism; D007908:Lens, Crystalline / Q000378:metabolism; D008297:Male; D008315:Malondialdehyde / Q000378:metabolism; D008892:Milk / Q000009:adverse effects*; D009281:Naphthalenes; D018384:Oxidative Stress / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D012307:Risk Factors
chemical_list: D009281:Naphthalenes; D017382:Reactive Oxygen Species; C031721:naphthalene; D008315:Malondialdehyde; D005978:Glutathione