Fig. 2

CD300f-IgG2a slows down axonal regeneration at 10 days after a sciatic nerve crush injury. Confocal images of whole mount tibial nerve at 18 mm distal from the crush site of uninjured or injured and injected nerves at 10 dpl (a). Thinner regenerating axons are seen in the tibial nerve (IgG2a and CD300f-IgG2a) compared with uninjured nerves. The group treated with the soluble receptor CD300f-IgG2a shows less axons growing distally through the tibial nerve than the IgG2a control group. b YFP-positive axons numbers are expressed as the percentage of contralateral axons at the indicated distance from the crush site at 10 dpl (n = 8 animals per group; *p < 0.05 vs. PBS and IgG2a). Representative footprints obtained from uninjured and at 10, 17, and 28 dpl are shown (c). The Sciatic Functional Index (SFI) walking track analysis revealed a strong tendency (p = 0.07) towards delayed functional recovery after treatment with CD300f-IgG2a when compared to IgG2a control animals (n = 8 mice per group). Representative micrographs of transverse sections of an uninjured sciatic nerve and at 28 days after crush injury and injection of IgG2a or CD300f-IgG2a show regenerated axons with thinner myelin at 28 dpl (d). Quantification shows a decreased number of myelinated axons in the tibial nerve with significantly fewer myelinated fibres in all crush injured animals (*p < 0.05 vs. uninjured group). The analysis of skin innervation at 28 dpl by the quantification of the number of intraepidermal nerve fibres in the plantar skin immunolabeled against protein gene product 9.5 (PGP 9.5) showed a significant reduced number of nerve fibres after crush injury, but no differences were observed between treated groups (*p < 0.05 vs. uninjured group). Scale bars: a, e 50 μm; d 10 μm