Fig. 2

Cochlear implantation following the elimination of cochlear macrophages. A Study design for cochlear implantation in PLX5662 treated mice. Cochlear implantation was performed on 2 groups of CX3CR1^+/GFP Thy1^+/YFP mice: one group was fed on chow with 1200 ppm of PLX-5622 (PLX) and the other group with control chow (No PLX) for 7 days. CI surgeries were performed on the left ear of both groups of mice after that (day 0). Following recovery from surgery, mice were continued with respective chow (PLX or No PLX) until they were killed at 10, 28, and 56 days post-implantation. Starting on post-operative day 7, mice within stimulation cages, connected to the CI processor were stimulated for 5 h per day, 5 days a week. B–M Fluorescent microscopic images of representative mid-modiolar, 30-µm-thick sections of the basal turn of the cochleae from respective groups. The following labels were used (Hoechst, blue), macrophages (CX3CR1-GFP, green), and neurons, (Thy1-YFP, yellow). Asterisks indicate the tract of the CI. In the presence of a functional cochlear implant, macrophage (CX3CR1 + cells) infiltration into the cochlea appears to be sustained until the end of the study period (56 days post-CI). This was associated with the infiltration of other cells labeled with nuclear labeling Hoechst