title: Methylene blue prevents retinal damage in an experimental model of ischemic proliferative retinopathy.
abstract: Perinatal asphyxia induces retinal lesions, generating ischemic proliferative retinopathy, which may result in blindness. Previously, we showed that the nitrergic system was involved in the physiopathology of perinatal asphyxia. Here we analyze the application of methylene blue, a well-known soluble guanylate cyclase inhibitor, as a therapeutic strategy to prevent retinopathy. Male rats (n = 28 per group) were treated in different ways: 1) control group comprised born-to-term animals; 2) methylene blue group comprised animals born from pregnant rats treated with methylene blue (2 mg/kg) 30 and 5 min before delivery; 3) perinatal asphyxia (PA) group comprised rats exposed to perinatal asphyxia (20 min at 37°C); and 4) methylene blue-PA group comprised animals born from pregnant rats treated with methylene blue (2 mg/kg) 30 and 5 min before delivery, and then the pups were subjected to PA as above. For molecular studies, mRNA was obtained at different times after asphyxia, and tissue was collected at 30 days for morphological and biochemical analysis. Perinatal asphyxia produced significant gliosis, angiogenesis, and thickening of the inner retina. Methylene blue treatment reduced these parameters. Perinatal asphyxia resulted in a significant elevation of the nitrergic system as shown by NO synthase (NOS) activity assays, Western blotting, and (immuno)histochemistry for the neuronal isoform of NOS and NADPH-diaphorase activity. All these parameters were also normalized by the treatment. In addition, methylene blue induced the upregulation of the anti-angiogenic peptide, pigment epithelium-derived factor. Application of methylene blue reduced morphological and biochemical parameters of retinopathy. This finding suggests the use of methylene blue as a new treatment to prevent or decrease retinal damage in the context of ischemic proliferative retinopathy.
authors.affiliation: Laboratorio de Neuropatología Experimental, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis," Facultad de Medicina, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina;
authors.forename: Manuel
authors.initials: M
authors.lastname: Rey-Funes
authors.affiliation: Angiogenesis Study Group, Center for Biomedical Research of La Rioja, Logroño, Spain; ilarrayoz@riojasalud.es.
authors.forename: Ignacio M
authors.identifier: 0000-0003-1629-152X
authors.initials: IM
authors.lastname: Larrayoz
authors.affiliation: Primera Cátedra de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, Buenos Aires, Argentina;
authors.forename: Juan C
authors.initials: JC
authors.lastname: Fernández
authors.affiliation: Laboratorio de Neuropatología Experimental, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis," Facultad de Medicina, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina;
authors.forename: Daniela S
authors.initials: DS
authors.lastname: Contartese
authors.affiliation: Laboratorio de Neuropatología Experimental, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis," Facultad de Medicina, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina;
authors.forename: Federico
authors.initials: F
authors.lastname: Rolón
authors.affiliation: Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico, Universidad Maimónides, Buenos Aires, Argentina;
authors.forename: Pablo I F
authors.initials: PI
authors.lastname: Inserra
authors.affiliation: Neurovascular Research Group, Department of Molecular, Cellular and Developmental Neurobiology, Instituto Cajal, Consejo Superior Investigaciones Científicas, Madrid, Spain; and.
authors.forename: Ricardo
authors.initials: R
authors.lastname: Martínez-Murillo
authors.affiliation: Laboratorio de Neuropatología Experimental, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis," Facultad de Medicina, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina;
authors.forename: Juan J
authors.initials: JJ
authors.lastname: López-Costa
authors.affiliation: Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y Diagnóstico, Universidad Maimónides, Buenos Aires, Argentina;
authors.forename: Verónica B
authors.initials: VB
authors.lastname: Dorfman
authors.affiliation: Angiogenesis Study Group, Center for Biomedical Research of La Rioja, Logroño, Spain;
authors.forename: Alfredo
authors.initials: A
authors.lastname: Martínez
authors.affiliation: Laboratorio de Neuropatología Experimental, Instituto de Biología Celular y Neurociencia "Prof. E. De Robertis," Facultad de Medicina, Universidad de Buenos Aires, Consejo Nacional de Investigaciones Científicas y Técnicas, Buenos Aires, Argentina; Laboratorio de Neurociencia, Facultad de Ciencias Médicas, Universidad Católica de Cuyo, San Juan, Argentina.
authors.forename: César F
authors.initials: CF
authors.lastname: Loidl
mesh_terms: D020533:Angiogenesis Inhibitors / Q000008:administration & dosage; D000818:Animals; D000831:Animals, Newborn; D000975:Antioxidants / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D008297:Male; D008751:Methylene Blue / Q000008:administration & dosage*; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D051381:Rats; D017207:Rats, Sprague-Dawley; D017382:Reactive Oxygen Species / Q000378:metabolism; D015861:Retinal Neovascularization / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology*; D012178:Retinopathy of Prematurity / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology*; D016896:Treatment Outcome
chemical_list: D020533:Angiogenesis Inhibitors; D000975:Antioxidants; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D008751:Methylene Blue
keywords: angiogenesis; ischemic proliferative retinopathy; methylene blue; nitric oxide; retina