[Influence of Nogo extracellular peptide residues 1-40 gene modification on survival and differentiation of neural stem cells after transplantation].

OBJECTIVE

To investigate the influence of Nogo extracellular peptide residues 1-40 (NEP1-40) gene modification on the survival and differentiation of the neural stem cells (NSCs) after transplantation.

METHODS

NSCs were isolated from the cortex tissue of rat embryo at the age of 18 days and identified by Nestin immunofluorescence. The lentiviruses were transduced to NSCs to construct NEP1-40 gene modified NSCs. The spinal cords of 30 Sprague Dawley rats were hemisected at T9 level. The rats were randomly assigned to 3 groups: group B (spinal cord injury, SCI), group C (NSCs), and group D (NEP1-40 gene modified NSCs). Cell culture medium, NSCs, and NEP1-40 gene modified NSCs were transplanted into the lesion site in groups B, C, and D, respectively at 7 days after injury. An additional 10 rats served as sham-operation group (group A), which only received laminectomy. At 8 weeks of transplantation, the survival and differentiation of transplanted cells were detected with counting neurofilament 200 (NF-200), glial fibrillary acidic portein (GFAP), and myelin basic protein (MBP) positive cells via immunohistochemical method; the quantity of horseradish peroxidase (HRP) positive nerve fiber was detected via HRP neural tracer technology.

RESULTS

At 8 weeks after transplantation, HRP nerve trace showed the number of HRP-positive nerve fibers of group A (85.17 +/- 6.97) was significantly more than that of group D (59.25 +/- 7.75), group C (33.58 +/- 5.47), and group B (12.17 +/- 2.79) (P < 0.01); the number of groups C and D were significantly higher than that of group B, and the number of group D was significantly higher than that of group C (P < 0.01). Immunofluorescent staining for Nestin showed no obvious fluorescence signal in group A, a few scattered fluorescent signal in group B, and strong fluorescence signal in groups C and D. The number of NF-200-positive cells and MBP integral absorbance value from high to low can be arranged as an order of group A, group D, group C, and group B (P < 0.05); the order of GFAP-positive cells from high to low was group B, group D, group C, and group A (P < 0.05); no significant difference was found in the percentage of NF-200, MBP, and GFAP-positive cells between group C and group D (P > 0.05).

CONCLUSION

NEP1-40 gene modification can significantly improve the survival and differentiation of NSCs after transplantation, but has no induction on cell differentiation. It can provide a new idea and reliable experimental base for the study of NSCs transplantation for SCI.