Microglial activation protects from vascular degeneration in a rat model of inflammatory retinal vasoregression.

Microglial activation represents a hallmark of inflammatory retinal diseases like diabetic retinopathy. Anti-inflammatory and especially microglia modulating approaches have been proposed as therapies for these diseases. In this study, clodronate-coated liposomes were intravitreally injected to investigate the effects of increased microglial activation on vasoregression in a model of retinal degeneration. Clodronate-coated liposomes, injected twice over a period of 5 weeks to study the effects of long term clodronate treatment on microglial activation, vasoregression (acellular capillary formation and pericyte loss) and to identify the pathways mediating the observed effects. 9-weeks-old PKD rats receiving two intravitreal injections at 4 and 8 weeks of age with Clodronate-coated liposomes (PKD + Clodronate, 5 samples), Controlliposomes (PKD + Controlliposomes, 6 samples) or PBS (PKD + PBS, 5 samples), 9-weeks-old uninjected PKD rats (PKD, 6 samples), 9-weeks-old SD rats receiving two intravitreal injections at 4 and 8 weeks of age with Clodronate-coated liposomes (SD + Clodronate, 6 samples) were analyzed, 9-weeks-old uninjected SD rats served as control group (SD, 6 samples).