title: Topical ocular dexamethasone decreases intraocular pressure and body weight in rats.
abstract: BACKGROUND
  Recently, topical dexamethasone-induced ocular hypertension and a consequent loss of retinal ganglion cells (RGCs) have been described in mice. This has been proposed as a model of steroid-induced glaucoma. In this study, we set up and evaluated a similar model in rats.
  
  
  RESULTS
  Ten-week old Sprague Dawley (SD) rats (N = 12) were used to evaluate the effect of topical 0.1% dexamethasone (50 μl) administered 3 times daily for 4 weeks. Sodium chloride (0.9%) was used in another group of rats (N = 12) that served as the controls. After 1 week, we observed a progressive decrease in body weight in the dexamethasone-treated rats compared both to the pre-treatment baseline and the vehicle-treated rats. In contrast to earlier work that showed elevated Intraocular pressure (IOP) following dexamethasone instillation in mice, IOP in the rats unexpectedly fell to 11.3 ± 1.3 mmHg in the treated eyes, compared to 14.8 ± 2.4 mmHg in the untreated eyes, after 3 weeks of topical dexamethasone (P = 0.032). Blood tests performed after 4 weeks of treatment showed a 3.3-fold increase in both plasma cholesterol (P < 0.001) and alanine transaminase (P = 0.019) in the dexamethasone-treated rats compared to the control rats. Meanwhile, topical steroid did not induce changes in either plasma blood glucose or glycated hemoglobin (HbA1c). We also did not detect changes in the expression of RGC markers (with real-time PCR) following the treatment.
  
  
  CONCLUSIONS
  In contrast to mice, which previously showed increased IOP following the topical administration of dexamethasone, the rats displayed a paradoxical reduction in IOP following a similar treatment. This was accompanied by a loss of body weight without affecting the level of blood glucose.
authors.affiliation: Department of Ophthalmology, Tohoku University Graduate School of Medicine, 1-1, Seiryo, Aoba, Sendai, Miyagi, 980-8574, Japan.
authors.forename: Kota
authors.initials: K
authors.lastname: Sato
authors.affiliation: Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Miyagi, Japan.
authors.forename: Koji M
authors.initials: KM
authors.lastname: Nishiguchi
authors.affiliation: Department of Ophthalmology, Tohoku University Graduate School of Medicine, 1-1, Seiryo, Aoba, Sendai, Miyagi, 980-8574, Japan.
authors.forename: Kazuichi
authors.initials: K
authors.lastname: Maruyama
authors.affiliation: Department of Ophthalmology, Tohoku University Graduate School of Medicine, 1-1, Seiryo, Aoba, Sendai, Miyagi, 980-8574, Japan.|Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Miyagi, Japan.
authors.forename: Satoru
authors.initials: S
authors.lastname: Moritoh
authors.affiliation: Department of Ophthalmology, Tohoku University Graduate School of Medicine, 1-1, Seiryo, Aoba, Sendai, Miyagi, 980-8574, Japan.
authors.forename: Kosuke
authors.initials: K
authors.lastname: Fujita
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Miyagi, Japan.
authors.forename: Yoshikazu
authors.initials: Y
authors.lastname: Ikuta
authors.affiliation: Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Miyagi, Japan.
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Kasai
authors.affiliation: Department of Ophthalmology, Tohoku University Graduate School of Medicine, 1-1, Seiryo, Aoba, Sendai, Miyagi, 980-8574, Japan. ntoru@oph.med.tohoku.ac.jp.|Department of Advanced Ophthalmic Medicine, Tohoku University Graduate School of Medicine, Miyagi, Japan. ntoru@oph.med.tohoku.ac.jp.|Department of Retinal Disease Control, Tohoku University Graduate School of Medicine, Miyagi, Japan. ntoru@oph.med.tohoku.ac.jp.
authors.forename: Toru
authors.initials: T
authors.lastname: Nakazawa
mesh_terms: D060433:Administration, Ophthalmic; D000410:Alanine Transaminase / Q000097:blood; D000818:Animals; D015415:Biomarkers; D001786:Blood Glucose / Q000032:analysis; D001835:Body Weight / Q000187:drug effects*; D002784:Cholesterol / Q000097:blood; D003907:Dexamethasone / Q000494:pharmacology* / Q000627:therapeutic use; D059865:Endoplasmic Reticulum Stress; D007429:Intraocular Pressure / Q000187:drug effects*; D008297:Male; D051379:Mice; D009798:Ocular Hypertension / Q000188:drug therapy*; D017207:Rats, Sprague-Dawley
chemical_list: D015415:Biomarkers; D001786:Blood Glucose; D003907:Dexamethasone; D002784:Cholesterol; D000410:Alanine Transaminase
keywords: Blood tests; Body weight; ER stress; Glaucoma; Glucocorticoide; Intraocular pressure