Modifications in Retinal Mitochondrial Respiration Precede Type 2 Diabetes and Protracted Microvascular Retinopathy.

Purpose: To characterize retinal mitochondrial respiration associated with type 2 diabetes (T2D) progression in a cone-rich diurnal rodent, the Nile rat (genus Arvicanthis, species niloticus).

Methods: Nile rats were fed a standard rodent diet that resulted in rising glucose levels from 6 months. Age-matched control animals were fed a high-fiber diet that prevented diabetes up to 18 months.

Five stages of progressive β-cell dysfunction in the laboratory Nile rat model of type 2 diabetes.

We compared the evolution of insulin resistance, hyperglycemia, and pancreatic β-cell dysfunction in the Nile rat (Arvicanthis niloticus), a diurnal rodent model of spontaneous type 2 diabetes (T2D), when maintained on regular laboratory chow versus a high-fiber diet. Chow-fed Nile rats already displayed symptoms characteristic of insulin resistance at 2 months (increased fat/lean mass ratio and hyperinsulinemia). Hyperglycemia was first detected at 6 months, with increased incidence at 12 months.