Fig. 5

Macrophage polarity shifts from the pro-inflammatory M1 to anti-inflammatory M2 phenotype in the day-12 CXB-NE group. There is a 27.5% reduction (p < .0001) in M1 pro-inflammatory macrophages in the day-12 CXB-NE group (b and f) compared to the day-12 DF-NE group (a and e). At day 18 the percentage of M1 macrophages increases by 56.7 to 85.7% in the nanomedicine treated (CXB-NE) rats, compared to day 12 (d and h). At day-18, levels of M1-positive macrophages rise to 91.4% per ROI in the DF-NE group (c and g). There are no significant differences in nanomedicine co-localization with M1 macrophages. The percentage of anti-inflammatory M2 macrophages increases significantly (p <.0001) by 69.0% in the day-12 CXB-NE group (j and n) compared to the DF-NE animals (i and m). At day-18, the proportion of M2 macrophages in the CXB-NE group (l and p) drops significantly (p < 0.0001) by 41.8%, whilst there is no significant difference in the DF-NE group at day-18 (k and o), compared to day-12 (i and m). M2 macrophages in the day-18 conditions show a significantly lower nanomedicine NIRF colocalization compared to both the DF-NE (Fisher’s exact test, p < .0001) and CXB-NE (Fisher’s exact test, p < .0001) day-12 groups. At day 18, the percentage of M2 macrophages that are positive for nanomedicine NIRF signal is significantly lower in the CXB-NE group (Fisher’s exact test, p = .000376) compared to the DF-NE group. All scale bars are 15 μm. The significance of M1 and M2 positive macrophage percent difference between conditions is represented as a Fisher’s exact test p-value; 95% confidence interval. n = 3 animals, 21–33 ROI