Reactive oxygen species and the structural remodeling of the visual system after ocular enucleation

• Published in: Neuroscience Vol. 170; no. 4; pp. 1249 - 1260
• Main Authors: Hernandes, M.S, Britto, L.R.G, Real, C.C, Martins, D.O, Lopes, L.R
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ltd 10-11-2010; Elsevier
• Subjects: Animals; antioxidants; Biological and medical sciences; Biomarkers - metabolism; Brain; dihydroethidium; Ethidium - analogs & derivatives; Ethidium - metabolism; Eye and associated structures. Visual pathways and centers. Vision; Eye Enucleation; Fundamental and applied biological sciences. Psychology; Geniculate Bodies - cytology; Geniculate Bodies - metabolism; Immunoblotting; Immunohistochemistry; Isoenzymes - antagonists & inhibitors; Isoenzymes - physiology; Male; NADPH oxidase; NADPH Oxidases - antagonists & inhibitors; NADPH Oxidases - physiology; Neurology; Neuronal Plasticity; Neurons - metabolism; Neurons - ultrastructure; Oxidation-Reduction; oxidative stress; Polymerase Chain Reaction; Rats; Rats, Wistar; Reactive Oxygen Species - metabolism; retinal removal; Superior Colliculi - cytology; Superior Colliculi - metabolism; Vertebrates: nervous system and sense organs; visual pathways; Visual Pathways - cytology; Visual Pathways - metabolism; DHE; antioxidants; polyethylene glycol–conjugated superoxide dismutase; superior colliculus; 7-NI; anti-microtubule-associated protein-2 antibody; phosphate buffer; SC; visual pathways; NADPH, oxidase; dorsal lateral geniculate nucleus; NADPH oxidase; reactive oxygen species; 7-nitroindazole; retinal removal; anti-neurofilament antibody; PEG-SOD; polyethylene glycol–conjugated catalase; diphenyleneiodonium chloride; PB; dihydroethidium; PEG-CAT; Nox; ROS; MAP-2; DPI; PAN; oxidative stress; DLG; Oxidative stress; Reactive oxygen species; Enzyme; Oxidase; Retina; Antioxidant; Eye; Enucleation; Visual system; Visual pathway; Oxidoreductases
• ISSN: 0306-4522; 1873-7544
• DOI: 10.1016/j.neuroscience.2010.07.065

Abstract Redox processes associated with controlled generation of reactive oxygen species (ROS) by NADPH oxidase (Nox) add an essential level of regulation to signaling pathways underlying physiological processes. We evaluated the ROS generation in the main visual relays of the mammalian brain, namely the superior colliculus (SC) and the dorsal lateral geniculate nucleus (DLG), after ocular enucleation in adult rats. Dihydroethidium (DHE) oxidation revealed increased ROS generation in SC and DLG between 1 and 30 days postlesion. ROS generation was decreased by the Nox inhibitors diphenyleneiodonium chloride (DPI) and apocynin. Real-time PCR results revealed that Nox 2 was upregulated in both retinorecipient structures after deafferentation, whereas Nox 1 and Nox 4 were upregulated only in the SC. To evaluate the role of ROS in structural remodeling after the lesions, apocynin was given to enucleated rats and immunohistochemistry was conducted for markers of neuronal remodeling into SC and DLG. Immunohistochemical data showed that ocular enucleation produces an increase of neurofilament and microtubule-associated protein-2 immunostaining in both SC and DLG, which was markedly attenuated by apocynin treatment. Taken together, the findings of the present study suggest a novel role for Nox-induced ROS signaling in mediating neuronal remodeling in visual areas after ocular enucleation.