PERIPHERAL-NERVE REGENERATION THROUGH NERVE GUIDES SEEDED WITH ADULT SCHWANN-CELLS

This study tested the usefulness of Schwann cells in the repair of a s evered nerve with a biosynthetic bridge or guide. Reinforced collagen nerve guides were used to bridge an Is mm gap in the sciatic nerve of 21 young adult rats. The animals were divided into three groups and th e guides were filled with: (i) more than 0.5 x 10(6) cultured syngenei c adult Schwann cells (group L, n = 12); (ii) less than 0.5 x 10(6) Sc hwann cells (Group S, n = 6); and (iii) phosphate buffered saline (con trol, n = 3). Schwann cells were pre-labelled with Hoechst dye. Regene ration was assessed functionally and histologically at 1, 2, 3 and 6months after surgery. Group L animals showed numerous regenerated axon s surrounded by implanted Schwann cells within the first month. The to tal number of myelinated fibres (12.5 x 10(3)) remained above normal u noperated values (7 x 10(3)) in long-term animals. Regenerated axons w ere found in Group S in the third month, but no Hoechst labelled cells were found. The number of myelinated fibres (3.9 x 10(3)) remained be low normal values in long-term animals. Control guides failed to suppo rt axonal regeneration. Functional recovery was evident at week 20 (Gr oup L) and week 30 (Group S) after surgery, with no difference in func tion between the two groups by the end of the study. Supplementing gui des with Schwann cells enhances regeneration of peripheral axons over a distance normally prohibitive. This effect is greatest in the early stages of regeneration (1-3 months) and is dependent on the number of cells implanted.