Infiltration of Proinflammatory M1 Macrophages into the Outer Retina Precedes Damage in a Mouse Model of Age-Related Macular Degeneration

Figure 1

Immunization with CEP-MSA leads to overt retinal degeneration in aged mice that resembles geographic atrophy with loss of photoreceptor cells, particularly in the BALB/c background. Histology of CEP-MSA versus naïve BALB/c or C57BL/6 eyes at different time points postimmunization. The RPE is located at the lower part of each image. The dark arrows show macrophage-like cells. CEP-MSA BALB/c mice show strong pathology since the early time points, starting with swollen RPE cells and leading to massive geographic atrophy at the late time point, including complete loss of the photoreceptor cells. The kinetics of pathology in CEP-MSA B6 mice is slower, but eventually there are focal lesions of the RPE such as vesiculation, as previously reported [21]. Representative images are shown (from 3–5 mice per group per experiment; two or three independent experiments were performed for each strain). INL: inner nuclear layer; ONL: outer nuclear layer; ROS: rod outer segment; RPE: retinal pigment epithelium. Images were obtained using a 63x oil objective, and the scale marker represents a 20 𝜇m length.