Fig. 4

Macrophage COX-2 and extracellular PGE2 expression is reduced following CXB-NE treatment. Macrophage expression of COX-2 enzyme and extracellular expression of its synthesized cytokine, PGE2, is measured at the ipsilateral sciatic nerve. There is a significant 56.5% reduction (Fisher’s exact test, p < 0.0001) of COX-2 positive macrophages at day-12 in the CXB-NE group (b and f), compared to the DF-NE group (a and e). Extracellular PGE2 levels are also significantly reduced (p < 0.0001) (i and k) in the day-12 CXB-NE group (k) compared to the day-12 DF-NE group (j). The representative images--j, k, l and m—have been converted to binary images to more clearly reveal the extracellular PGE2, which is counted by applying a size threshold during analysis. The larger particles denote COX-2 stained macrophages, and the smaller particles represent extracellular PGE2, examples of which are represented within the red boxes. At day-18, the proportion of COX-2 positive macrophages in the DF-NE (c and g) and CXB-NE (d and h) groups rises to levels comparable to the day-12 DF-NE group (e). Extracellular PGE2 is significantly reduced at day-18 in both the DF-NE (i and l) (p < .0001) and CXB-NE (i and m) (p < .0001) groups. Macrophages positive for COX-2 were analyzed to report on their colocalization with nanomedicine NIRF signal (white segment in e-f). A significantly higher co-localization of nanomedicine with COX-2 positive macrophages was observed in the day-12 CXB-NE condition (p < .0001). All scale bars are 15 μm. The significance of COX-2 positive macrophage percent difference between conditions is represented as a Fisher’s exact test p-value; 95% confidence interval. Extracellular PGE2 data are represented as mean ± SEM (n = 3 animals, 16–26 ROI; ****p < .0001, one-way ANOVA with Tukey’s post hoc test)