title: The sand rat, Psammomys obesus, develops type 2 diabetic retinopathy similar to humans.
abstract: OBJECTIVE
  Diabetic retinopathy (DR) is a leading cause of blindness, yet pertinent animal models are uncommon. The sand rat (Psammomys obesus), exhibiting diet-induced metabolic syndrome, might constitute a relevant model.
  
  
  METHODS
  Adult P. obesus (n = 39) were maintained in captivity for 4 to 7 months and fed either vegetation-based diets (n = 13) or standard rat chow (n = 26). Although plant-fed animals exhibited uniform body weight and blood glucose levels over time, nearly 60% of rat chow-raised animals developed diabetes-like symptoms (test group). Animals were killed, and their eyes and vitreous were processed for immunochemistry.
  
  
  RESULTS
  Compared with plant-fed animals, diabetic animals showed many abnormal vascular features, including vasodilation, tortuosity, and pericyte loss within the blood vessels, hyperproteinemia and elevated ratios of proangiogenic and antiangiogenic growth factors in the vitreous, and blood-retinal barrier breakdown. Furthermore, there were statistically significant decreases in retinal cell layer thicknesses and densities, accompanied by profound alterations in glia (downregulation of glutamine synthetase, glutamate-aspartate transporter, upregulation of glial fibrillar acidic protein) and many neurons (reduced expression of protein kinase Cα and Cξ in bipolar cells, axonal degeneration in ganglion cells). Cone photoreceptors were particularly affected, with reduced expression of short- and mid-/long-wavelength opsins. Hypercaloric diet nondiabetic animals showed intermediate values.
  
  
  CONCLUSIONS
  Simple dietary modulation of P. obesus induces a rapid and severe phenotype closely resembling human type 2 DR. This species presents a valuable novel experimental model for probing the neural (especially cone photoreceptor) pathogenic modifications that are difficult to study in humans and for screening therapeutic strategies.
authors: Département de Neurobiologie des Rythmes, Institut des Neurosciences Cellulaires et Intégratives, Strasbourg, France.
authors: Tounès
authors: T
authors: Saïdi
authors: Sihem
authors: S
authors: Mbarek
authors: Samy
authors: S
authors: Omri
authors: Francine
authors: F
authors: Behar-Cohen
authors: Rafika Ben
authors: RB
authors: Chaouacha-Chekir
authors: David
authors: D
authors: Hicks
mesh_terms: D000821:Animal Feed; D000818:Animals; D001786:Blood Glucose / Q000378:metabolism; D001835:Body Weight / Q000502:physiology; D002452:Cell Count; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000503:physiopathology*; D003930:Diabetic Retinopathy / Q000473:pathology* / Q000503:physiopathology*; D004195:Disease Models, Animal; D002149:Energy Intake / Q000502:physiology; D005136:Eye Proteins / Q000378:metabolism; D005849:Gerbillinae; D006801:Humans; D006943:Hyperglycemia / Q000503:physiopathology; D008297:Male; D024821:Metabolic Syndrome / Q000503:physiopathology; D009457:Neuroglia / Q000473:pathology; D009765:Obesity / Q000503:physiopathology; D017949:Retinal Cone Photoreceptor Cells / Q000473:pathology; D012165:Retinal Ganglion Cells / Q000473:pathology; D017948:Retinal Rod Photoreceptor Cells / Q000473:pathology; D014822:Vitreous Body / Q000378:metabolism
chemical_list: D001786:Blood Glucose; D005136:Eye Proteins