title: Neuroprotective and antioxidant effects of ghrelin in an experimental glaucoma model.
abstract: Damage to retinal ganglion cells due to elevation of intraocular pressure (IOP) is responsible for vision loss in glaucoma. Given that loss of these cells is irreversible, neuroprotection is crucial in the treatment of glaucoma. In this study, we investigated the possible antioxidant and neuroprotective effects of ghrelin on the retina in an experimental glaucoma model. Twenty-one Sprague-Dawley rats were randomly assigned to three groups comprising seven rats each. The rats in the control group were not operated on and did not receive any treatment. In all rats in the other groups, IOP was increased by cauterization of the limbal veins. After creation of the IOP increase, saline 1 mL/kg or ghrelin 40 μg/kg was administered intraperitoneally every day for 14 days in the vehicle control group and ghrelin groups, respectively. On day 14 of the study, the eyes were enucleated. Levels of malondialdehyde (MDA), nitric oxide (NO), and nitric oxide synthase-2 (NOS2) in anterior chamber fluid were measured. The retinas were subjected to immunohistochemistry staining for glial fibrillary acidic protein (GFAP), S-100, and vimentin expression. Mean levels of MDA, NO, and NOS2 in the aqueous humor were higher in the vehicle control group than in the control group (P<0.05). Mean levels of MDA, NO, and NOS2 in the ghrelin group did not show a significant increase compared with levels in the control group (P>0.05). Retinal TUNEL and immunohistochemistry staining in the vehicle control group showed an increase in apoptosis and expression of GFAP, S-100, and vimentin compared with the control group (P<0.05). In the ghrelin group, apoptosis and expression of GFAP, S-100, and vimentin was significantly lower than in the vehicle control group (P<0.05). This study suggests that ghrelin has antioxidant and neuroprotective effects on the retina in an experimental glaucoma model.
authors.affiliation: Department of Ophthalmology, Elazığ Training and Research Hospital, Fırat University, Elazığ, Turkey.
authors.forename: Nagehan
authors.initials: N
authors.lastname: Can
authors.affiliation: Department of Ophthalmology, School of Medicine, Fırat University, Elazığ, Turkey.
authors.forename: Onur
authors.initials: O
authors.lastname: Catak
authors.affiliation: Department of Ophthalmology, School of Medicine, Fırat University, Elazığ, Turkey.
authors.forename: Burak
authors.initials: B
authors.lastname: Turgut
authors.affiliation: Department of Ophthalmology, School of Medicine, Fırat University, Elazığ, Turkey.
authors.forename: Tamer
authors.initials: T
authors.lastname: Demir
authors.affiliation: Department of Biochemistry, School of Medicine, Fırat University, Elazığ, Turkey.
authors.forename: Nevin
authors.initials: N
authors.lastname: Ilhan
authors.affiliation: Department of Histology and Embryology, School of Medicine, Fırat University, Elazığ, Turkey.
authors.forename: Tuncay
authors.initials: T
authors.lastname: Kuloglu
authors.affiliation: Department of Pathology, School of Medicine, Fırat University, Elazığ, Turkey.
authors.forename: Ibrahim Hanifi
authors.initials: IH
authors.lastname: Ozercan
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D004195:Disease Models, Animal; D054439:Ghrelin / Q000494:pharmacology*; D005901:Glaucoma / Q000188:drug therapy* / Q000473:pathology; D020287:In Situ Nick-End Labeling; D007429:Intraocular Pressure / Q000187:drug effects*; D018696:Neuroprotective Agents / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012160:Retina / Q000378:metabolism / Q000473:pathology; D012165:Retinal Ganglion Cells / Q000187:drug effects / Q000473:pathology
chemical_list: D000975:Antioxidants; D054439:Ghrelin; D018696:Neuroprotective Agents
keywords: antioxidant; experimental glaucoma; ganglion cells; ghrelin; neuroprotective