Fig. 3
Quantification of macrophage and cellular density following cochlear implantation in basal cochlear turn. Following the tracing of the scala tympani, Rosenthal canal (RC), and lateral wall of the base of the cochlea, volumetric measurements were conducted using IMARIS image analysis software. Counts of CX3CR1 + macrophages in each region were determined with a supervised automated counting system, enhanced by a custom-developed macro, and their density was quantified. For each cochlea, the average density was calculated from three midmodiolar sections. Macrophage densities were analyzed in (A) the scala tympani, (B) the spiral ganglion, and (C) the lateral wall of the cochlea. Additionally, nuclei labeled with Hoechst 3342 in 30-µm-thick sections were counted and their density was determined within the traced scala tympani base (D). Error bars represent SEM. Statistical analyses were performed using two-way ANOVA with Tukey’s multiple comparisons. Results demonstrate that cochlear implantation leads to the infiltration of CX3CR1 + macrophages across all three regions. Dexamethasone-eluting implants significantly reduce macrophage and cellular infiltration up to 112 days post-implantation. In contrast, local dexamethasone injection reduces macrophage and cellular infiltration at 10 days post-implantation but fails to sustain this effect at 28 days post-implantation, as shown by the Multiple Mann-Whitney test.
