title: The distribution of Mn2+ in rabbit eyes after topical administration for manganese-enhanced MRI.
abstract: OBJECTIVE
  To analyze the distribution of Mn(2+) in rabbit eyes after topical administration of Mncl2 for manganese-enhanced MRI.
  
  
  METHODS
  Forty-eight Chinese white rabbits were divided into three groups. In group 1 (n = 4), the baseline concentration of Mn(2+) in aqueous, vitreous and serum samples were analyzed. In group 2 and 3, the rabbits received one topical instillation (20 μL) of Mncl2 (1 mol • L(-1)). In group 2 (n = 40), aqueous, vitreous and serum samples were collected and analyzed at predetermined time points (0.5, 1, 2, 4, 6, 12, 24, 48, 72 and 168 hours postdose). Assays were performed using inductively coupled plasma-mass spectrometer (ICP-MS). In group 3 (n = 4), after topical administration of Mncl2, dynamic manganese-enhanced MRI (MEMRI) was performed at predetermined time points. The signal-to-noise ratio (SNR) was calculated to evaluate the enhancements of eyes.
  
  
  RESULTS
  After topical administration, the maximum concentrations of Mn(2+) in the aqueous and vitreous samples were 11.1641 ± 0.7202 (2 hours) and 1.5622 ± 0.1567 (12 hours). In group 3, the maximum enhancement of aqueous humor (SNR = 108.81 ± 10.65) appeared at 2 hours postdose, whereas, no significant changes were detected in vitreous.
  
  
  CONCLUSIONS
  Mn(2+) could distribute into aqueous humor rapidly after topical administration of Mncl2, whereas, the concentration of Mn(2+) in vitreous body fluctuated in a narrow range over the course. The uptake of Mn(2+) in retina may involve several different pathways.
authors.affiliation: Department of Ophthalmology, First Affiliated Hospital of Zhengzhou University Zhengzhou, China.
authors.forename: Shenzhi
authors.initials: S
authors.lastname: Liang
authors.affiliation: School of Food and Bioengineering, Zhengzhou University of Light Industry Zhengzhou, China.
authors.forename: Miao
authors.initials: M
authors.lastname: Liang
authors.affiliation: Department of Ophthalmology, First Affiliated Hospital of Zhengzhou University Zhengzhou, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Zhu
authors.affiliation: Department of MRI, First Affiliated Hospital of Zhengzhou University Zhengzhou, China.
authors.forename: Jingliang
authors.initials: J
authors.lastname: Cheng
authors.affiliation: Department of MRI, First Affiliated Hospital of Zhengzhou University Zhengzhou, China.
authors.forename: Zitao
authors.initials: Z
authors.lastname: Yang
mesh_terms: D000287:Administration, Topical; D000818:Animals; D002712:Chlorides / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D017895:Manganese Compounds / Q000008:administration & dosage* / Q000493:pharmacokinetics*; D009883:Ophthalmic Solutions; D011817:Rabbits
chemical_list: D002712:Chlorides; D017895:Manganese Compounds; D009883:Ophthalmic Solutions; C025340:manganese chloride
keywords: Drug distribution; ICP-MS; MEMRI; manganese; topical administration