A simple protocol for isolating microglia from adult mouse brain

OBJECTIVES: Although microglia are activated in adult and aged brains resulting in neurodegenerative and neuroinflammatory disorders, most of the cell culture studies on microglia deal with neonatal microglia because of ease of isolation. Microglia could be isolated from adult brains, but it requires separation by density gradient centrifugation, magnetic beads, etc. Here, we describe a simple protocol of isolating highly purified microglia from adult mouse brains. METHODS: Our protocol involves dilution with sterile PBS or media, regular centrifugation, and plating on poly-D-lysine-coated flasks. RESULTS: These adult microglia expressed the inducible nitric oxide synthase in response to preformed α-syn fibril, an etiological reagent of Parkinson’s disease, and bacterial lipopolysaccharides, one of the prototype proinflammatory stimuli. Moreover, these adult microglia exhibited phagocytosis, which was stimulated by LPS treatment. CONCLUSIONS: These results suggest that adult microglia isolated by our procedure are functional and that these adult microglia could be used for studies related to neurodegenerative disorders.