title: The Effects of Metformin on Obesity-Induced Dysfunctional Retinas.
abstract: The purpose of this study was to determine the effects of metformin on dysfunctional retinas in obesity-induced type 2 diabetic mice.
  
  
  
  A high-fat diet (HFD)-induced diabetic mouse model (C57BL/6J) was used in this study. After 2 months of the HFD regimen, HFD mice were given daily metformin through oral gavage. Body weights, glucose tolerance, and retinal light responses were monitored regularly. Fluorescein angiography (FA) was used to assess changes in retinal vasculature. Ocular tissues (retina, vitreous, and lens) were harvested and analyzed for molecular changes as determined by immunofluorescent staining, Western blot analysis, and cytokine profiling.
  
  
  
  Starting 1 month after the diet regimen, mice fed the HFD had mildly compromised retinal light responses as measured by electroretinography (ERG), which worsened over time compared to that in the control. In HFD mice treated with metformin, systemic glucose levels reverted back to normal, and their weight gain slowed. Metformin reversed HFD-induced changes in phosphorylated protein kinase B (pAKT), extracellular signal-regulated kinase (pERK), and 5'AMP-activated protein kinase (pAMPK) in the retina. However, metformin treatments for 3 months did not restore the retinal light responses nor lessen the HFD-induced retinal neovascularization, even though it did reduce intraocular inflammation.
  
  
  
  Although metformin was able to reverse systemic changes induced by HFD, it was not able to restore HFD-caused retinal light responses or deter neovascularization.
authors.affiliation: Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States.
authors.forename: Andy Jeesu
authors.initials: AJ
authors.lastname: Kim
authors.affiliation: Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States.
authors.forename: Janet Ya-An
authors.initials: JY
authors.lastname: Chang
authors.affiliation: Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States.
authors.forename: Liheng
authors.initials: L
authors.lastname: Shi
authors.affiliation: Department of Veterinary Physiology and Pharmacology, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States.
authors.forename: Richard Cheng-An
authors.initials: RC
authors.lastname: Chang
authors.affiliation: Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States.
authors.forename: Michael Lee
authors.initials: ML
authors.lastname: Ko
authors.affiliation: Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, Texas, United States 3Texas A&M Institute for Neuroscience, Texas A&M University, College Station, Texas, United States.
authors.forename: Gladys Yi-Ping
authors.initials: GY
authors.lastname: Ko
mesh_terms: D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D015153:Blotting, Western; D016207:Cytokines / Q000378:metabolism; D003921:Diabetes Mellitus, Experimental; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism; D003930:Diabetic Retinopathy / Q000175:diagnosis / Q000209:etiology / Q000517:prevention & control*; D004596:Electroretinography; D005451:Fluorescein Angiography; D005654:Fundus Oculi; D007004:Hypoglycemic Agents / Q000494:pharmacology; D008297:Male; D008687:Metformin / Q000494:pharmacology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000150:complications* / Q000175:diagnosis / Q000378:metabolism; D012160:Retina / Q000473:pathology* / Q000503:physiopathology; D012171:Retinal Vessels / Q000473:pathology
chemical_list: D001786:Blood Glucose; D016207:Cytokines; D007004:Hypoglycemic Agents; D008687:Metformin