To better understand the regional distribution of peripheral macrophages identified using flow cytometry from the total brain, we crossed CX3CR1eGFP/eGFP and CCR2RFP/RFP mice to yield CX3CR1eGFP/+ CCR2RFP/+ mice (Fig. 2a), allowing for the differentiation of microglia (CX3CR1eGFP) and IMs (CCR2RFP). CCR2RFP macrophages were identifiable in the cortex, cerebellum, and the hippocampus of ethanol-fed mice (Fig. 2b). Although there was a general trend toward an increase in the number of peripheral CCR2RFP+ IMs after chronic alcohol in all three brain regions, IMs were twice as numerous in the hippocampus in the ethanol-fed mice (Fig. 2c). Interestingly, there was no change in the number of CX3CR1eGFP/+ microglia in any of the brain regions (Fig. 2d).
