Depletion of late-recruited macrophages affects regeneration by impairing mesenchymal cell behavior but not cell death. (a and b) Representative images show cell death (green) in intact and amputated fin at (a) 48 hpA and (b) 24 hpA using confocal microscopy. (a) Cell death was detected using Acridine Orange staining in larvae in which all macrophages were depleted with L-clodronate treatment 24 h before amputation (L-clodronate 1) or not (L-PBS). (b) Cell death was detected using Acridine Orange staining in larvae in which late macrophages were depleted with L-clodronate treatment at 6 hpA (L-clodronate 2) or not (L-PBS). Dotted lines outline the fin, asterisks show autofluorescence of the pigments and arrowheads show dead cells. Scale bar=100 μm. (c,d) Cell death counts in indicated conditions (Nlarvae=7–18 per group from two independent experiments, mean values±S.E.M., *P<0.05). (e) Tg(rcn3:gal4/UAS:Ds-Red) larvae were amputated at 3 dpf and injected with either L-PBS or L-clodronate at 6 hpA. Fin images are representative confocal maximum projections of Ds-Red (magenta) fluorescence in mesenchymal cells of the fins at 72 hpA. Arrowheads show round mesenchymal cells at the wound of late macrophage-depleted larvae. Scale bar=100 μm
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