Repair of Peripheral Nerve Defects Using a Polyvinylidene Fluoride Channel Containing Nerve Growth Factor and Collagen Gel in Adult Rats

OBJECTIVE As effectiveness of the autologous graft in the repair of long nerve defects is very limited an effective substitute is needed. This study was conducted to determine the poled polyvinylidene fluoride (PVDF) tube as an alternative to nerve autograft. MATERIALS AND METHODS The left sciatic nerve was transected in 45 male Wistar rats. The animals were then divided randomly into three groups: in an epineural group the nerve was sutured end to end; in an autograft group a 10 mm piece of sciatic nerve was cut, rotated 180° and sutured in the nerve gap; and in a nerve guidance channel group (NGC), PVDF, tube containing nerve growth factor (NGF) and collagen gel was placed in the gap. In a control (n=15) group the sciatic nerve was exposed but not transected. To determine axonal regeneration, retrograde DiI tracer was injected into the gastrocnemius muscle. One week later, retrograde-labeled neurons were counted in the L4-L6 spinal segments and one way ANOVA analysis was performed to compare groups. Neuronal morphology changes were studied by electron microscopy. RESULTS Significant statistical decreases in the mean number of labeled motoneurons were observed in all surgical groups compared to the control group; and in the autograft and the NGC groups compared to epinural suture group (p<0.01). No significant difference in the mean number of motoneurons was observed between the autograft and NGC groups. Chromatin condensation, dilated endoplasmic reticulum and large vacuoles were observed in the autograft and NGC groups. CONCLUSION Regarding the positive effects of PVDF tube containing NGF and Collagen gel on the sciatic nerve regeneration, authors suggest that it may be useful in peripheral nerve repair.