Fig. 8

Lineage tracing of microglia show their increase in the inner retina and appearance of CD11b⁺/Iba-1⁺ myeloid leukocytes after IR injury. CX3CR1-CreERT2 knockin driver mice crossed with mT/mG reporter mice were used to lineage trace microglia as GFP⁺. A 4-week washout period after TAM treatment was used to clear GFP⁺ Cre-recombined monocytes from circulation prior to IR injury. A Representative images of GFP, CD11b, and Iba-1 expressing cells in inner (GCL + IPL) and deep (INL + OPL) layers of Sham and IR-injured retinas at 4 days after injury. Note that essentially all CD11b⁺ cells in the Sham retina are GFP⁺ microglia expressing Iba-1. Quantification and categorization of CD11b⁺ cell densities (cells per retinal area) in the inner layers (GCL + IPL) (B), deep layers (INL + OPL) (C), and combined layers (GCL + IPL + INL + OPL) (D). Note that the density of CD11b⁺/Iba-1⁺/GFP⁺ microglia nearly doubles in the inner layers, while not changing in the deep layers. An appreciable population of CD11b⁺/Iba-1⁺/GFP^neg myeloid leukocytes appears in both layers after IR injury, while there are relatively few myeloid leukocytes that are negative for Iba-1. *p ≤ 0.05, **p ≤ 0.01, and ***p ≤ 0.001 for IR versus Sham by u test