Objective: To observe the result of reconstructing quadriceps femoris function in the paraplegia rats by using the 7th cervical nerve root (C7) transposition with autologous and allogeneic neural transplantation.
Methods: Twenty 16-week-old SPF male Wistar rats were adopted to prepare frozen sciatic nerve. Thirty-six Wistar rats were divided into 2 groups (group A and group B, n = 18). The left paraplegia model was established with left spinal cord hemisection by the micro scissors under the operation microscope. After the model establishment, the homolateral autologous sciatic nerve was bridged with the femoral nerve root by the translocation of C7 in group A, while the allogeneic sciatic nerve was bridged with the femoral nerve root by the translocation of C7 in group B. At 16 weeks and 24 weeks after operation, 9 rats in each group were selected for the neuroelectric-physiological test and then the histomorphology of the nerves was observed under the microscope and the electron microscope. The fresh weight recovery rate of quadriceps femoris was calculated.
Results: At 16 and 24 weeks after operation, the nerve action-evoked potential (NAP) was (1.14 +/- 0.07) mV and (1.21 +/- 0.07) mV in group A, and (0.87 +/- 0.06) mV and (0.99 +/- 0.05) mV in group B; the nerve conduction velocity (NCV) was (17.34 +/- 2.15) m/s and (19.00 +/- 3.02) m/s in group A, and (11.23 +/- 1.45) m/s and (12.54 +/- 1.59) m/s in group B, respectively, indicating significant differences (P < 0.05) between 2 groups. At 16 and 24 weeks after operation, HE staining and Bielschowsky staining showed that group A had a large number of nerve fiber regeneration, with a regular arrange of axons; while group B had little nerve fiber regeneration with a scattered arrange of axons. At 24 weeks after operation, images in TEM showed a large number of regeneration myelinated nerve fibers and a small number of unmyelinated nerve fibers through the transplanted nerve in two groups. At 16 weeks after operation, the number of myelinated nerve fibers in group A and group B was (438 +/- 79) and (196 +/- 31)/vision, the areas of myelinated nerve fibers were (5 596.00 +/- 583.94) and (4 022.63 +/- 615.75) microm2/vision; after 24 weeks, the number of myelinated nerve fibers in groups A and B were (642 +/- 64) and (321 +/- 75)/vision, the areas of myelinated nerve fibers were (6 689.50 +/- 1 142.10) and (4 733.00 +/- 982.22) microm2/vision, indicating significant differences between two groups (P < 0.05). There was no statistically significant difference (P > 0.05) in the wet weight recovery rate of quadriceps between group A and group B at 16 weeks (87.96% +/- 4.93% vs. 86.47% +/- 7.47%) and at 24 weeks after operation (90.10% +/- 4.22% vs. 87.66% +/- 3.14%).
Conclusion: C7 transposition combined with autograft and allograft of sciatic nerve can reconstruct the partial function of the quadriceps femoris in paraplegia rats. The effect of graft is better than that of graft obviously.