Abstract
Purpose :
We investigated the susceptibility of retinal neurovascular coupling and neural function to type 2 diabetes.
Methods :
The longitudinal changes in retinal neuronal function and blood flow response to a 3-minute flicker light stimulation and a 10-minute systemic hyperoxia were evaluated every 2 weeks in diabetes db/db mice and their corresponding controls (db/m) from age 8 to 20 weeks. The retinal blood flow and neural activity were assessed using laser speckle flowgraphy and electroretinography (ERG), respectively.
Results :
The body weight and blood glucose levels were significantly higher in db/db mice while systemic blood pressure and ocular perfusion pressure were unchanged with age. The resting retinal blood flow was comparable between two groups throughout the study. Flicker light and hyperoxia elicited a consistent increase and decrease in retinal blood flow, respectively, in db/m mice independent of age. However, these flow responses were significantly diminished in db/db mice at 8 weeks of age and then became unresponsive to stimulations at 12 weeks. Subsequently, the ERG implicit times for oscillatory potential wave was significantly increased at 14 weeks of age while the amplitude of all waves and the implicit time of a-wave and b-wave remained unchanged.
Conclusions :
The retinal blood flow responses to flicker light and hyperoxia are gradually diminished during the progression of diabetes and the ERG alteration occurs at the time corresponding to exhausted retinal blood flow regulation. The deficiency of neurovascular coupling and flow regulation in the retina appears to precede neural dysfunction in the mouse with type 2 diabetes.
This is a 2021 ARVO Annual Meeting abstract.