title: Aqueous Humor Outflow Physiology in NOS3 Knockout Mice.
abstract: OBJECTIVE
  To investigate the role of endothelial nitric oxide synthase (eNOS) on conventional outflow function using NOS3 knockout (KO) mice.
  
  
  METHODS
  Intraocular pressure was measured in both NOS3 KO and wild type (WT) by rebound tonometry. Outflow facility was measured by perfusing enucleated mouse eyes at multiple pressure steps. A subset of eyes was sectioned and stained for histology. Mock aqueous humor ± the nitric oxide (NO) donors nitroprusside dihydrate (SNP) or S-Nitroso-N-Acetyl-D,L-Penicillamine (SNAP) was perfused into enucleated eyes. SNP and SNAP was administered topically at 0, 1, 2, and 3 hours while the contralateral eyes served as vehicle controls. Intraocular pressure was measured in both eyes before and after the last drug treatment.
  
  
  RESULTS
  Intraocular pressure was higher in KO mice (18.2 ± 0.7 mm Hg vs. 13.9 ± 0.5 mm Hg, mean ± SEM, n = 30, P < 0.05), and pressure-dependent conventional drainage was significantly lower (0.0058 ± 0.0005 μL/min/mm Hg, mean ± SEM, n = 21) compared with WT mice (0.0082 ± 0.0013 μL/min/mm Hg, n = 23, P < 0.05). No obvious morphological differences in iridiocorneal angle tissues were observed in hematoxylin and eosin (H&E)-stained sections. SNP and SNAP significantly increased pressure-dependent drainage in KO animals (n = 12, P < 0.05). In WT mice, SNP and SNAP caused a significant increase in pressure dependent drainage (n = 12, P < 0.05) to a similar degree as in KO mice. Topical application of SNP significantly reduced IOP in WT and KO mice (n = 12, P < 0.05), but SNAP did not change IOP significantly (n = 19).
  
  
  CONCLUSIONS
  NOS3 KO mice have elevated IOP, which is likely the result of reduced pressure-dependent drainage. These findings are consistent with human data showing polymorphisms in the NOS3 gene associate with ocular hypertension and the development of glaucoma.
authors.affiliation: Research Centre Eye and ENT Hospital, Shanghai Medical College, Fudan University, China 2Key Laboratory of Myopia, Ministry of Health, Fudan University, China 3Shanghai Key Laboratory of Visual Impairment and Restoration, Eye and ENT Hospital, Shanghai Me.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Lei
authors.affiliation: Research Centre Eye and ENT Hospital, Shanghai Medical College, Fudan University, China 3Shanghai Key Laboratory of Visual Impairment and Restoration, Eye and ENT Hospital, Shanghai Medical College, Fudan University, China.
authors.forename: Xuejin
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Shanghai Key Laboratory of Visual Impairment and Restoration, Eye and ENT Hospital, Shanghai Medical College, Fudan University, China 4Department of Ophthalmology and Vision Science, Eye and ENT Hospital, Shanghai Medical College, Fudan University, China.
authors.forename: Maomao
authors.initials: M
authors.lastname: Song
authors.affiliation: Research Centre Eye and ENT Hospital, Shanghai Medical College, Fudan University, China 3Shanghai Key Laboratory of Visual Impairment and Restoration, Eye and ENT Hospital, Shanghai Medical College, Fudan University, China.
authors.forename: Jihong
authors.initials: J
authors.lastname: Wu
authors.affiliation: Key Laboratory of Myopia, Ministry of Health, Fudan University, China 3Shanghai Key Laboratory of Visual Impairment and Restoration, Eye and ENT Hospital, Shanghai Medical College, Fudan University, China 4Department of Ophthalmology and Vision Science, E.
authors.forename: Xinghuai
authors.initials: X
authors.lastname: Sun
mesh_terms: D000818:Animals; D001082:Aqueous Humor / Q000502:physiology*; D004195:Disease Models, Animal; D005901:Glaucoma / Q000201:enzymology / Q000503:physiopathology*; D007150:Immunohistochemistry; D007429:Intraocular Pressure; D051379:Mice; D018345:Mice, Knockout; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism*; D009798:Ocular Hypertension / Q000201:enzymology / Q000503:physiopathology*; D014065:Tonometry, Ocular; D014129:Trabecular Meshwork / Q000503:physiopathology*
chemical_list: D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse