The microglial system in the eye and brain in response to stimuli in vivo

Microglial cells function as first responders to signal inflammation, react to injuries by creating a wall to block invaders, and clear debris from the site. To better understand the modulation of microglia in inflammation and injury of eye and brain, we developed a morphological and orienting classification system of each stage of microglia, calling it the 'Spider Effect'. We transected the olfactory bulb of rats and examined the activation of the microglial system histologically. Six stages of bidirectional microglial activation (A) and deactivation (R) were observed. Our findings support a morphologically defined stepwise activation and deactivation of microglia cells. This relates to inflammation in the eye due to noxious stimuli, injury, or increase in pressure. Future studies may address the reported modulation of the microglial system in retina and optic nerve head in acute and chronic glaucoma.