Ultrastructural Changes in Spinal Motoneurons and Locomotor Functional Study after Sciatic Nerve Repair in Conduit Tube

OBJECTIVES Motor deficit and neuron degeneration is seen after nerve transection. The aim of this study is to determine whether a poled polyvinelidene fluoride (PVDF) tube with other supportive strategies can protect the neuronal morphology and motor function after sciatic nerve transaction in rats. MATERIALS AND METHODS After transection of the left sciatic nerve in 60 male Wistar rats (200-250 g), the epineural group was sutured end to end. In the autograft rats, a 10 mm piece of sciatic nerve was rotated 180 °C and sutured back into the nerve gap. In the nerve guidance channel (NGC) group, polarized piezoelectric PVDF tube containing NGF and collagen gel was sutured in the gap. In control group sciatic nerve was removed (10 mm) without repair. After one, four and eight weeks, the L4-L6 spinal cord segment was removed for histological study using transmission electron microscope. Functional outcome was assessed using the Basso, Bresnahan and Beattie (BBB) locomotor scale at both four and eight weeks after the lesion. RESULTS Chromatin condensation was seen after 4 weeks in the repair groups. Cell membrane shrinkage and mitochondrial degeneration was observed after 4 and 8 weeks respectively, in the autografted and NGC rats. In the control group, chromatin condensation, cell membrane shrinkage with mitochondrial degeneration and vacuolization of perikaryon was seen after 1, 4 and 8 weeks, respectively. At 56 days, the functional recovery of the epineural rats significantly increased in comparison to the other groups (P< 0.05). CONCLUSION The epineural suture has more efficacies, and NGC may be used as a proper substitute for autograft in nerve injury.