Fl/fl) genotype primer pair and primers pair that amplifies a 190-bp fragment of Cre recombinase coding region (forward primer, 59-AATTTGCCTGCATTACCGGTCGATGCAACG-39 and reverse primer 59CCATTTCCGGTTATTCAACTTGCACCATGC-39). Mice were housed under diurnal lighting conditions and allowed free CP21 web access to food and water. All animals were used in accordance with the guidelines of the Association for Research in Vision and Ophthalmology for the Use of Animals in Ophthalmology and Vision Research, and experimental protocols for this study were approved by the Institutional Animal Care and Use Committee (IACUC) of Case Western Reserve University.Materials and Methods Creation of Gclc Floxed MouseGclc conditional knockout (Gclcfl/fl) target ES 18334597 cells with C57BL/6 genetic background were obtained from the European Conditional Knockout Mouse Program (EUCOMM). The Gclcfl/ fl exon 2 is flanked by two loxP sites, and the Neo cassette is flanked by two FRT sites. Microinjection of ES cells into C57BL/Age-Related Nuclear Cataract Animal ModelFigure 3. Comparison of lens anterior surfaces of 6 mos wild type and Homo-LEGSKO mouse lenses vitally stained for DNA and ROS. Fresh lenses were stained with both Hoechst 33342 and Dihydrorhodamine 123 (DHR). The Lens anterior was scanned using 10X objective, and 65 mm deep into the cortex and 0.8 mm layer Z-scan was MedChemExpress Felypressin performed and projection image was obtained with same method for both WT and LEGSKO lenses. (A) and (C). Comparison of DNA staining with Hoechst 33342 (blue) of the anterior surface of Wt and LEGSKO lenses. (B) and (D). Comparison of vital staining for ROS fluorescence with DHR stain (green) of the same surface areas. doi:10.1371/journal.pone.0050832.gQuantitative Determination of Reduced Glutathione (GSH) and Oxidized Glutathione (GSSG)Eyes were removed immediately after sacrifice. Lenses were homogenized in 200 ml ice-cold 5 metaphosphoric acid and 0.6 sulfosalicylic acid mixture in 0.1 M potassium phosphate buffer and 5 mM EDTA buffer (pH 7.5). The supernatant was analyzed for GSH and GSSG using glutathione reductase (GR) and b-NADPH enzymatic recycle method followed by colorimetric assay after derivatization with 5,59-dithio-bis(2-nitrobenzoic acid) (DTNB) as described [37]. Commercially available GSH (G6529, Sigma, St. Louis) and GSSG (49740, Sigma, St. Louis) were used for standard curve calibration.Lens fibers were subdivided onto cortex and nuclear fraction by a freeze-thawing technique whereby quick freezing at 280uC was followed by thawing at room temperature for 1 min, creating a clear white opacity in nucleus. The cortical and nucleus regions can then be easy separated for GSH and GSSG determination.c-Glutamyl Cysteine Ligase Activity AssayGcl activity in lens extract was measured using monobromobimane derivatization and HPLC analysis with fluorescence detection as previously reported [38].Age-Related Nuclear Cataract Animal ModelFigure 4. Slit-lamp image of LEGSKO and age matched wild type mouse lens. (A). Representative images of HOM-LEGSKO mouse lens at 4 and 9 months compared with age matched control wild type mouse lens. The same mouse was followed over a period of 9 months and lens images were taken every two months. (B). Slit-lamp images were taken periodically and lens opacity/cataract of any size were recorded for 9 months in homozygous LEGSKO mice vs. age matched wild type mice (n = 30 mice per group). LEGSKO mice developed lens opacities and cataract at much higher rate compared t.Fl/fl) genotype primer pair and primers pair that amplifies a 190-bp fragment of Cre recombinase coding region (forward primer, 59-AATTTGCCTGCATTACCGGTCGATGCAACG-39 and reverse primer 59CCATTTCCGGTTATTCAACTTGCACCATGC-39). Mice were housed under diurnal lighting conditions and allowed free access to food and water. All animals were used in accordance with the guidelines of the Association for Research in Vision and Ophthalmology for the Use of Animals in Ophthalmology and Vision Research, and experimental protocols for this study were approved by the Institutional Animal Care and Use Committee (IACUC) of Case Western Reserve University.Materials and Methods Creation of Gclc Floxed MouseGclc conditional knockout (Gclcfl/fl) target ES 18334597 cells with C57BL/6 genetic background were obtained from the European Conditional Knockout Mouse Program (EUCOMM). The Gclcfl/ fl exon 2 is flanked by two loxP sites, and the Neo cassette is flanked by two FRT sites. Microinjection of ES cells into C57BL/Age-Related Nuclear Cataract Animal ModelFigure 3. Comparison of lens anterior surfaces of 6 mos wild type and Homo-LEGSKO mouse lenses vitally stained for DNA and ROS. Fresh lenses were stained with both Hoechst 33342 and Dihydrorhodamine 123 (DHR). The Lens anterior was scanned using 10X objective, and 65 mm deep into the cortex and 0.8 mm layer Z-scan was performed and projection image was obtained with same method for both WT and LEGSKO lenses. (A) and (C). Comparison of DNA staining with Hoechst 33342 (blue) of the anterior surface of Wt and LEGSKO lenses. (B) and (D). Comparison of vital staining for ROS fluorescence with DHR stain (green) of the same surface areas. doi:10.1371/journal.pone.0050832.gQuantitative Determination of Reduced Glutathione (GSH) and Oxidized Glutathione (GSSG)Eyes were removed immediately after sacrifice. Lenses were homogenized in 200 ml ice-cold 5 metaphosphoric acid and 0.6 sulfosalicylic acid mixture in 0.1 M potassium phosphate buffer and 5 mM EDTA buffer (pH 7.5). The supernatant was analyzed for GSH and GSSG using glutathione reductase (GR) and b-NADPH enzymatic recycle method followed by colorimetric assay after derivatization with 5,59-dithio-bis(2-nitrobenzoic acid) (DTNB) as described [37]. Commercially available GSH (G6529, Sigma, St. Louis) and GSSG (49740, Sigma, St. Louis) were used for standard curve calibration.Lens fibers were subdivided onto cortex and nuclear fraction by a freeze-thawing technique whereby quick freezing at 280uC was followed by thawing at room temperature for 1 min, creating a clear white opacity in nucleus. The cortical and nucleus regions can then be easy separated for GSH and GSSG determination.c-Glutamyl Cysteine Ligase Activity AssayGcl activity in lens extract was measured using monobromobimane derivatization and HPLC analysis with fluorescence detection as previously reported [38].Age-Related Nuclear Cataract Animal ModelFigure 4. Slit-lamp image of LEGSKO and age matched wild type mouse lens. (A). Representative images of HOM-LEGSKO mouse lens at 4 and 9 months compared with age matched control wild type mouse lens. The same mouse was followed over a period of 9 months and lens images were taken every two months. (B). Slit-lamp images were taken periodically and lens opacity/cataract of any size were recorded for 9 months in homozygous LEGSKO mice vs. age matched wild type mice (n = 30 mice per group). LEGSKO mice developed lens opacities and cataract at much higher rate compared t.
