Longitudinal histology of regenerated nerves for HE staining and anti-neurofilament staining under light microscopy. a, normal nerve specimen. b, midpoint view of regenerated nerve in autograft group. c, midpoint view of regenerated nerve in collagen/PCL NCs group. A1,B1,C1, HE staining; A2-A4,B2-B4,C2-C5, anti-neurofilament staining; A3,B3,C3, magnified views of the square area in A2,B2,C2, respectively. A4,B4,C4, corresponding specimens as blank controls without primary antibody incubation. C5, overview image of the mid-portion of regenerated nerve in collagen/PCL NCs at 4 × magnification. Regenerated nerve fibers in autograft and collagen/PCL NCs groups were positively stained with neurofilament 200 similarly as normal nerve. Electrospun nerve conduits almost degraded and only a few of residual materials (black arrows) could be found inside the wall area 4 months postoperatively (C5). (Bar in A1,A2,B1,B2,C1,C2 = 100 μm; bar in A3,A4,B3,B4,C3,C4 = 50 μm; bar in C5 = 500 μm).