Schwann cell morphology and myelination are affected in the nerve coils.

<p><b>ABC</b>) Transverse section of non-lesioned (A), LV-GArGFP injected (B) and LV-GDNF injected (C) nerves, stained for Schwann cells (green), GDNF (red) and cell nuclei (blue). Non-lesioned and control-injected nerves show a homogenous distribution of Schwann cells. In LV-GDNF treated nerves, there are nerve coil areas with an increased density of Schwann cells. <b>A’B’C’</b>) Same images as ABC, but with green and blue channels removed to visualise GDNF staining. In intact and lesioned control nerves, GDNF immunoreactivity does not exceed background levels. In LV-GDNF treated animals, high GDNF immunoreactivity is limited to the nerve coils. <b>DE</b>) In intact control nerves (D), and outside the coils in LV-GDNF treated nerves (E) Schwann cells have the normal, ring-like morphology (white arrowheads). This morphology appears to be disrupted in the coils. <b>F</b>) Strong p75 immunoreactivity (green) was observed inside nerve coils, indicating the presence of large numbers of immature Schwann cells. The majority of axons (blue) inside the nerve coil are not myelinated (myelin basic protein, red). <b>GHI</b>) Higher magnifications of (F). A small number of axons inside the nerve coil appear to be myelinated, but the myelin sheath was thin and only weakly immunoreactive for myelin basic protein. Scalebar in C; 200 um, Scalebar in E and G; 25 um.