Investigative ophthalmology & visual science · 2015
Retinal Ganglion Cell Loss and Mild Vasculopathy in Methylene Tetrahydrofolate Reductase (Mthfr)-Deficient Mice: A Model of Mild Hyperhomocysteinemia.
СтатьяПоддержка NIH: внешняя программаНазвание и аннотация: Перевод пока не подготовлен
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Markand Shanu, Saul Alan, Roon Penny, Prasad Puttur, Martin Pamela, Rozen Rima, Ganapathy Vadivel, Smith Sylvia B
Аннотация
PURPOSE: Methylenetetrahydrofolate reductase (Mthfr) is a key enzyme in homocysteine-methionine metabolism. We investigated Mthfr expression in retina and asked whether mild hyperhomocysteinemia, due to Mthfr deficiency, alters retinal neurovascular structure and function.
METHODS: Expression of Mthfr was investigated at the gene and protein level using quantitative (q) RT-PCR, in situ hybridization, immunoblotting, and immunohistochemistry (IHC). The Mthfr+/+ and Mthfr+/- mice were subjected to comprehensive evaluation using ERG, funduscopy, fluorescein angiography (FA), spectral-domain optical coherence tomography (SD-OCT), HPLC, and morphometric and IHC analysis of glial fibrillary acidic protein (GFAP) at 8 to 24 weeks.
RESULTS: Gene and protein analyses disclosed widespread retinal expression of Mthfr. Electroretinography (ERG) revealed a significant decrease in positive scotopic threshold response in retinas of Mthfr+/- mice at 24 weeks. Fundus examination in mice from both groups was normal; FA revealed areas of focal vascular leakage in 20% of Mthfr+/- mice at 12 to 16 weeks and 60% by 24 weeks. The SD-OCT revealed a significant decrease in nerve fiber layer (NFL) thickness at 24 weeks in Mthfr+/- compared to Mthfr+/+ mice. There was a 2-fold elevation in retinal hcy at 24 weeks in Mthfr+/- mice by HPLC and IHC. Morphometric analysis revealed an approximately 20% reduction in cells in the ganglion cell layer of Mthfr+/- mice at 24 weeks. The IHC indicated significantly increased GFAP labeling suggestive of Müller cell activation.
CONCLUSIONS: Mildly hyperhomocysteinemic Mthfr+/- mice demonstrate reduced ganglion cell function, thinner NFL, and mild vasculopathy by 24 weeks. The retinal phenotype is similar to that of hyperhomocysteinemic mice with deficiency of cystathionine-β-synthase (Cbs) reported earlier. The data support the hypothesis that hyperhomocysteinemia may be causative in certain retinal neurovasculopathies.
METHODS: Expression of Mthfr was investigated at the gene and protein level using quantitative (q) RT-PCR, in situ hybridization, immunoblotting, and immunohistochemistry (IHC). The Mthfr+/+ and Mthfr+/- mice were subjected to comprehensive evaluation using ERG, funduscopy, fluorescein angiography (FA), spectral-domain optical coherence tomography (SD-OCT), HPLC, and morphometric and IHC analysis of glial fibrillary acidic protein (GFAP) at 8 to 24 weeks.
RESULTS: Gene and protein analyses disclosed widespread retinal expression of Mthfr. Electroretinography (ERG) revealed a significant decrease in positive scotopic threshold response in retinas of Mthfr+/- mice at 24 weeks. Fundus examination in mice from both groups was normal; FA revealed areas of focal vascular leakage in 20% of Mthfr+/- mice at 12 to 16 weeks and 60% by 24 weeks. The SD-OCT revealed a significant decrease in nerve fiber layer (NFL) thickness at 24 weeks in Mthfr+/- compared to Mthfr+/+ mice. There was a 2-fold elevation in retinal hcy at 24 weeks in Mthfr+/- mice by HPLC and IHC. Morphometric analysis revealed an approximately 20% reduction in cells in the ganglion cell layer of Mthfr+/- mice at 24 weeks. The IHC indicated significantly increased GFAP labeling suggestive of Müller cell activation.
CONCLUSIONS: Mildly hyperhomocysteinemic Mthfr+/- mice demonstrate reduced ganglion cell function, thinner NFL, and mild vasculopathy by 24 weeks. The retinal phenotype is similar to that of hyperhomocysteinemic mice with deficiency of cystathionine-β-synthase (Cbs) reported earlier. The data support the hypothesis that hyperhomocysteinemia may be causative in certain retinal neurovasculopathies.
Предметные рубрики MeSH
AnimalsDNADisease Models, AnimalElectroretinographyFluorescein AngiographyFundus OculiGene Expression RegulationHomocystinuriaHyperhomocysteinemiaImmunoblottingImmunohistochemistryMethylenetetrahydrofolate Reductase (NADPH2)MiceMice, TransgenicMuscle SpasticityPsychotic DisordersReal-Time Polymerase Chain ReactionRetinal Ganglion CellsTomography, Optical Coherence