Research Article

Anti-Inflammatory Strategy for M2 Microglial Polarization Using Retinoic Acid-Loaded Nanoparticles

Figure 3

RA-NP modulated microglia activation and morphology in LPS-treated hippocampal slice cultures. Murine organotypic hippocampal slice cultures (P7) were treated with RA-NP (10 μg/mL) or free RA (0.4 μM), and their effect on cell morphology was quantified in an inflammatory context (100 ng/mL LPS, 24 hours). (a) RA-NP treatment significantly reduced cell bodies; free RA (0.40 μM) had no effect (; compared to untreated cells; # compared to LPS). (b) RA-NP treatment (10 μg/mL) significantly promoted a higher number of microglial processes while free RA (0.40 μM) had no effect (; compared to untreated cells, ### compared to LPS). (c) RA-NP treatment (10 μg/mL) significantly promoted an increase in length of microglial processes. Free RA had no effect (; compared to untreated cells, ## compared to LPS). (d) Representative brain slices were stained for CD11b (green; top panel), and skeletonized microglial cells are shown in the bottom panel. Nuclear staining in blue. (e) Microglial cells (in red) internalized RA-NP (in green). Colocalization is highlighted in the merged image. Nuclear staining in blue. Scale bar 10 μm.
(a)
(b)
(c)
(d)
(e)