An enhanced staining method K-B-2R staining for three-dimensional nerve reconstruction

BACKGROUND: Three-dimensional (3D) reconstruction of human peripheral nerves, as a useful tool to understand the nerve internal information and functional basis, has become an important area of research in the peripheral nerve field. METHODS: In this study, we proposed a two-dimensional (2D) Karnovsky–Roots toluidine blue ponceau 2R (K-B-2R) staining method based upon conventional Karnovsky–Roots staining. It significantly improved the ability to display nerve fascicles, motor and sensory nerve fiber textures. In this method, Karnovsky–Roots staining was carried out, followed by toluidine blue counterstain and ponceau 2R counterstain. RESULTS: Comparisons were conducted between the three methods in staining of median nerve sections, which showed similar distribution characters in acetylcholinesterase-positive sites. The additional counterstaining did not change the basis of Karnovsky–Roots staining. However, the resulting images from this new method significantly facilitated the subsequent 3D nerve reconstruction and 3D printing. CONCLUSIONS: These results show that the new staining method significantly enhanced the display qualities of nerve fascicle edges and fiber textures of motor and sensory nerves and facilitated 3D nerve reconstruction.