Schwann cell culture and characterization of p75NTR . After two rounds of purification, postnatal rat Schwann cells at the third passage presented a phase-refractile, bipolar or tripolar cell character, with a growth tendency to connect with each other. A, light microscopy of Schwann cells (× 100 magnification). B, anti- p75NTR staining. C, nuclei DAPI staining. D, image merged from B and C (Bar = 10 μm).