OBJECTIVETo explore the effects of the transplantation of collagen-chitosan nerve scaffold containing glial cell line-derived neurotrophic factor(GDNF)gene modified schwann cells on the recovery of long-distance sciatic nerve defect.

METHODSThe rat models of 8 mm long-distance sciatic nerve defect were established and divided into three groups, with 6 rats in each group. In GDNF-Sch group, the defect was repaired by GDNF modified Schwann cells combined with collagen-chitosan nerve scaffold. In Sch group, the defect was repaired by Schwann cells combined with collagen-chitosan nerve scaffold. In the control group, the defect was repaired by autologous nerve graft. Sciatic function index(SFI)was detected 3, 6, and 12 weeks after surgery. After 12 weeks, the tibialis anterior muscle wet weight, electrophysiology, and regenerated nerve morphology were detected.

RESULTSThe SFI in the operated side significantly differed among these three groups after 6 and 12 weeks(P<0.05). Along with prolonged treatment, the GDNF-Sch group had similar SFI recovery with the control group but significantly better SFI recovery than Sch group. After 12 weeks, the sensory nerve conduction velocity in the GDNF-Sch and Sch group was not significantly different(P>0.05)but was significantly lower than that in the control group(P<0.05). Both the GDNF-Sch group and Sch group had significantly lower sensory nerve amplitude comparing with the control group(P<0.05), whereas that in the GDNF-Sch group was significantly higher than that in the Sch group(P<0.05). GDNF-Sch group and the control group had significantly higher motor nerve conduction velocity and amplitude than Sch group(P<0.05), while no such statistically significant difference was seen between the two groups(P >0.05). After 12 weeks, the wet weight of the bridging side of the tibial muscle in the control group, Sch group, and GDNF-Sch group was(0.360±0.020), (0.250±0.018), and(0.310±0.025)g, which were significantly lower than the control side [(0.440±0.031), (0.420±0.024), and(0.430±0.027)g, respectively(P<0.05)]. Muscle wet weight in bridge side of GDNF-Sch group and the control group were significantly higher than in Sch group(P<0.05), but it was not significantly different between the GDNF-Sch group and the control group(P>0.05).

CONCLUSIONTransplantation of collagen-chitosan nerve scaffold containing GDNF gene modified Schwann cells can remarkably facilitate sciatic nerve defect recovery, with a milimar effectiveness as autologous nerve grafting.