[Effects of neurotrophic factor 3 gene modified SC on sciatic nerve regeneration in rats].
OBJECTIVE
To investgate the effects of neurotrophic factor 3 (NT-3) genes modified SC on facilitating nerve regeneration and protecting neuronal survival after the sciatic nerve transection in rats.


METHODS
The double sciatic nerves were harvested from 3-day-old Wistar rats and the SCs were separated, cultured and purified with double enzyme digestion and adherent culture. The third generation purified SCs were used. The NT-3 cDNA gene was transfected into cultured SCs by using cationic liposome. The NT-3 expression were identified by ELISA after 1, 2, 4 and 8 weeks. The plasmids expressing NT-3 genes were transfected into SCs with lipofectamine. The purity of SCs were detecting before and after modified with NT-3. The nerve-grafting complexes were constructed by SCs (3 x 10(7)/mL) modified NT-3, third generation SCs (3 x 10(7)/mL), NT-3 gene, respectively. And the nerve-grafting complexes were combined with ECM gel and PLGA conduit. Forty-eight adult SD rats were made the models of the right sciatic nerve defect (10 mm). According to the nerve-grafting complexes which were repaired the sciatic nerve defects, the models were divided into 4 groups randomly (n=12): group A (ECM gel and PLGA conduits), group B (SC, ECM gel and PLGA conduits), group C (NT-3 gene, ECM gel and PLGA conduits) and group D (NT-3 modified SC, ECM gel and PLGA conduits). At 2, 4, 6, 8 and 12 weeks after operation, the nerve gross were observed. Electrophysiological examination, histological observation and transmission electron microscope observation were performed at 12 weeks after operation.


RESULTS
The concentrations of NT-3 protein were 0.39 +/- 0.25, 0.76 +/- 0.22, 1.06 +/- 0.38 and 1.61 +/- 0.35 at 1, 2, 4 and 8 weeks after operation; showing statistically significant differences (P < 0.05). The purity of SCs was 94.7% +/- 2.1% and 95.6% +/- 2.5% before and after modified with NT-3, respectively; showing a statistically significant difference (P < 0.05). The feet of injury rats began inflammation and ulcer, which healed at 12 weeks in group D, followed by groups C and B, but which was serious in group A gradually. The observations of gross, sections under microscope and transmission electron microscope at 12 weeks showed the regeneration of defect nerve was best in group D, followed by groups C and B, and group A was worst. There were statistically significant differences (P < 0.05) in latent period, amplitude, motor nerve conduction velocity, the number and thickness of axon, the diameter of nerve fiber, the percentage of the nerve tissue area between group A and groups B, C, D, between groups B, C and group D at 12 weeks. At 12 weeks after operation, the transmission electron microscope showed observation the maturation of medullary sheath was best in group D, followed by groups C and B, and group A was worst.


CONCLUSIONS
The nerve-grafting complex of NT-3 genes modified SCs could repair injured nerve. The competence is superior to SCs and neurotrophic factors.
Dong
Yuzhen
Y
Department of Orthopedics, the First Affiliated Hospital of Xinxiang Medical College, Weihui Henan, 453100, PR China. dongyuzhen1998@163.com
Chen
Zhenbing
Z
Hong
Guangxiang
G
D000818:Animals; D017690:Cell Transplantation; D002478:Cells, Cultured; D005260:Female; D008297:Male; D009414:Nerve Growth Factors / Q000235:genetics / Q000502:physiology*; D009416:Nerve Regeneration; D051381:Rats; D017207:Rats, Sprague-Dawley; D017208:Rats, Wistar; D012584:Sciatic Nerve / Q000166:cytology; D014162:Transfection
D009414:Nerve Growth Factors