Abstract
Purpose :
While there is strong evidence about microglial activation in DR, the character, cause, and causal role of microglial activation leading to blood-retinal barrier (BRB) alteration are yet unknown. In the current study, using microglia depletion experiments, we have determined the role of microglia in the alteration of the BRB in diabetic retinopathy.
Methods :
Diabetes was induced in c57bl/6j mice using streptozotocin. Microglial depletion was achieved in the animal models using 290mg/kg CSF1R inhibitor PLX3397 (Pexidartinib) formulated into AIN-76A standard diet. The following groups of animals were: A) Non-diabetic control (AIN-76A regular diet), B) Diabetic mice on regular diet (3 months), C) Diabetic mice fed PLX3397 infused diet for 3 months, D) Diabetic mice fed PLX3397 diet for 2 months followed by a regular diet for 1 month. Microglial depletion was assessed by flow cytometry. Vascular permeability was measured for extravascular albumin using Western Blot analysis of retinas. Multiplex ELISA was used to determine inflammatory factors in the retinal tissues.
Results :
Retinas of diabetic mice fed with PLX3397 infused diet showed significantly decreased microglia cells compared with diabetic mice on the regular diet (p=0.05), and significantly reduced the extravasation of albumin compared with diabetic animals on the normal diet (p =0.05). Multiplex ELISA showed that the levels of IL6, MMP2, and RAGE in the retinas of diabetic animals on PLX3397 diet were significantly reduced compared to diabetic animals on the regular diet. In Group D, the levels of these inflammatory molecules increased significantly in the retinas of diabetic animals in the recovery phase.
Conclusions :
Overall, we have shown evidence that microglia are essential in the alteration of the BRB in diabetes.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.