title: In vitro extraction of intra-corneal iron using reverse iontophoresis and vitamin C.
abstract: OBJECTIVE
  The aim of this study was to optimize reverse iontophoretic (RI) extraction of ferric/ferrous ions from the cornea.
  
  
  METHODS
  Group I consisted of the right eye corneas from 20 normal rabbits. Corneal blood staining was induced in 60 right eyes. The corneal depths from the endothelium to the epithelium layers were divided into three groups by slit-lamp examination: Group II, one-third corneal thickness; Group III, one-half corneal thickness; Group IV, full corneal thickness. RI was performed using vertical diffusion cells. The lower chamber was loaded with glutathione bicarbonate Ringer's buffer (GBR; pH 7.0) or vitamin C (12.5 mg/mL) and GBR (pH 7.0), while the upper chamber was filled with 1 mL GBR. Progress of corneal blood staining removal was evaluated.
  
  
  RESULTS
  Application of 1.5 mA to the cornea increased flux by 1.72- and 2.19-fold in Groups III and IV, respectively, but not in Groups I or II, compared to the control. When vitamin C was included, we observed significant flux increases in the controls (1.5-, 2.06-, 2.60-, and 4.59-fold) for Groups I, II, III, and IV, and under RI conditions for Groups III and IV. Following RI, the corneal endothelia appeared similar to corneas from untreated control rabbits, while Draize scores were zero.
  
  
  CONCLUSIONS
  These results suggested that extracellular ferric/ferrous ions could be extracted from the cornea in vitro by RI, and that vitamin C reduced Fe(3+) to Fe(2+) in the cornea and altered its permselectivity, thus increasing the RI contribution to iron extraction.
authors.affiliation: Department of Ophthalmology, the First Affiliated Hospital of Harbin Medical University, 23 Youzheng St., Nangang District, Harbin, 150001, China.
authors.forename: Jian-Hai
authors.initials: JH
authors.lastname: Bai
authors.forename: Sheng
authors.initials: S
authors.lastname: Su
authors.forename: Lei
authors.initials: L
authors.lastname: Huang
authors.forename: Yan-Yan
authors.initials: YY
authors.lastname: Zhang
authors.forename: Yun-Song
authors.initials: YS
authors.lastname: Wang
authors.forename: Mei-Hua
authors.initials: MH
authors.lastname: Guo
authors.forename: Hong-Bin
authors.initials: HB
authors.lastname: Yang
authors.forename: Hao
authors.initials: H
authors.lastname: Cui
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000494:pharmacology*; D003315:Cornea / Q000187:drug effects; D003316:Corneal Diseases / Q000378:metabolism / Q000628:therapy*; D004195:Disease Models, Animal; D005260:Female; D006486:Hemosiderosis / Q000378:metabolism / Q000628:therapy*; D007478:Iontophoresis / Q000379:methods*; D058085:Iron Compounds / Q000378:metabolism*; D008297:Male; D011817:Rabbits; D013054:Spectrophotometry, Atomic
chemical_list: D000975:Antioxidants; D058085:Iron Compounds; D001205:Ascorbic Acid