Fig 1.
In vivo imaging of macrophages.
(A) Macrophages labeled with/without XenoLight DiR® were injected into mice via tail vein. The time course of total fluorescence signal intensities was evaluated for 7 days. Scale bar, 10 mm. (B) Different numbers (2×106/body or 5×106/body) of macrophages labeled with XenoLight DiR® were injected into mice. The total fluorescence signal intensities were monitored for 7 days. (C) Seven days after the injection of macrophages labeled with XenoLight DiR®, mice were euthanized. The major organs were harvested to detect the fluorescence signal, showing that labeled macrophages homed specifically in the liver, spleen and lung. Scale bar, 10 mm.
Fig 2.
Effect of liposomal clodronate on macrophages in vitro and in vivo.
(A) The viability of mouse macrophage-like RAW264.7 cells after liposomal clodronate (lipo-CL2MDP) treatment (48 hours) was evaluated using a colorimetric assay. Liposomal PBS (lipo-PBS) was used as a control. The percentage viability was calculated as follows: (OD value in the presence of each concentration of lipo-CL2MDP or lipo-PBS/OD value with no additive) ×100. The results reflect the mean ± SD of three independent determinations (representative experiment of three performed). The asterisk denotes statistical significance (*P < .05). (B) The effects of lipo-CL2MDP on macrophages injected into mice were analyzed by an image analyzer. Lipo-CL2MDP or lipo-PBS was administered into mice 3 hours after the injection of macrophages labeled with XenoLight DiR®. The time course of total fluorescence signal intensities was evaluated for 168 hours. The asterisk denotes statistical significance (*P < .05). (C) Lipo-CL2MDP or lipo-PBS was administered into mice 3 hours after the injection of macrophages labeled with XenoLight DiR®. The fluorescence signal intensities in different organs were compared after 7 days. Labeled macrophages home specifically in the liver, spleen and lung (upper panel). However, in the subgroup treated with lipo-CL2MDP (lower panel), fluorescence signal was detected slightly (liver and spleen) and minimally (lung). Scale bar, 10 mm. (D) Pathological assessment of macrophages after lipo-CL2MDP treatment. Liver (left panels), spleen (middle panels) and lung (right panels) specimens were stained with H&E (top panels in each subgroup) and the macrophages were detected with the anti-mouse F4/80 monoclonal antibody (bottom panels in each subgroup). Representative images of three mice are shown. Original magnification, ×400. Scale bar, 80 μm.