Fig. 5

Repeated PAD4 dose regimen led to a faster resolution of the inflammatory response upon laser-induced injury. a–e Inflammatory response of untreated and PAD4 inhibitor-treated Ccr2^RFPCx3cr1^GFP mice. a, b Images show differences in microglia and PL recruitment on days 1 and 7 in the damaged site (delimited by magenta dashes). While microglia and PL cluster in injury in untreated mice, PAD4 inhibitor-treated retinas have non-significant PL infiltration, and microglia are evenly distributed within the retinal parenchyma. Inserts show morphological stages of microglial activation in untreated and PAD4 inhibitor-treated mice. The arrow indicates the direction in which the damaged site is located. c, d Quantification of the number of GFP⁺ microglia and RFP⁺ PL per lesion of untreated and PAD4 inhibitor-treated Ccr2^RFPCx3cr1^GFP retinas before injury (baseline) and at pre-defined time points (day 0, 1, 4, 7, 10 and 14). Significant differences (**p < 0.01, ***p < 0.001 and ****p < 0.0001) between untreated and PAD4 inhibitor-treated mice were determined by using a post-hoc Bonferroni one-way ANOVA test (n = 8). e Quantification of the polarity coefficient of untreated and PAD4 inhibitor-treated microglia after injury (day 0) and at pre-defined time points (day 1, 4, 7, 10 and 14). Significant differences (*p < 0.1 and ***p < 0.001) between untreated and PAD4 inhibitor-treated mice were determined by using a post-hoc Bonferroni one-way ANOVA test (n = 8). For both groups, day 0 was chosen as calibrator [NRQ (normalized relative quantification) = 1]. f Quantification of the primary and terminal processes per cell after injury (day 0) and at pre-defined time points (days 1, 4, 7, 10 and 14). Significant differences (*p < 0. 1) between untreated and PAD4 inhibitor-treated mice were determined by using a post-hoc Bonferroni one-way ANOVA test (n = 8). Field of view is approximately ≈ 425 µm