| Objective To investigate the effects of Neurogenesin-1 (Ng1) gene on differentiation of endogenous neural stem cells and functional recovery after spinal cord injury.Methods 36 rats were randomly divided into two groups: experimental group and control group, n = 18. After all rats received a spinal cord injury using modified Allen's method, Ng1 recombinant plasmid and blank plasmid were transfected into the damaged areas of the two groups respectively by Alzet pumps. At 24h, 1wk,2wk, 3wk and 4wk after SCI, BBB Rating Scale was used for observe the recovery of motor function. At 14 or 28 days after injury, double immunofluorescence and histopathologic examinations was performed to study the differentiation of the adult endogenous neural precursors and ultrastructural changes after SCI.Results(1)From 1 to 4 weeks after SCI, the BBB scores in Ng1 group was significantly higher compared with that in control group(P<0.05),and at 4 weeks the BBB scores of the experimental group(16.80±1.79) was significantly better than that of the control group(9.60±1.67),the difference was statistically significant(P<0.01).(2)At 14 days after injury, the HE staining of histology showed a little better in the Ng1 group than that in the control group.And the morphology in the Ng1 group was close to the normal spinal cord tissue at 28 days after injury.Electron microscope observation showed that only less axonal degenerations could be found in the white matter and the thin myelin sheath was mainly observed in the Ng1 group at 4 weeks post-injury, which was much better than the control group.(3)The number of BrdU+/MAP-2+ newborn neurons and BrdU+/GFAP+ newborn amoeytes showed much difference between in control group and Ng1 group at 14 days or 28 days after injury(P<0.05).Immunohistochemieal analysis showed siganificant difference in the number of the inducing differentiated newborns neurons and astrocytes from endogenous neural stem cells in Ng1 gene treated rats compared with control rats.At the same times, it could be easily noticed that the mean numbers of Nestin+/Brdu+ newborn endogenous neural stem cells were significantly numerous than that in control group.Conclusion(1)Ng1 recombinant plasmid which was transfected into the damaged spinal cord by Alzet bump could give a clue for the neurogenesis.Ng1 gene could promoted the differentiation of endogenous neural stem cells into neurons and remyelination and inhibited the differentiation of endogenous neural stem cells into astroeytes.(2)The BBB locomotor function scores were obvious higher in Ng1 group than that in control Group at 28 days after injury. The results showed Ng1 gene could promote the functional recovery after spinal cord injury.
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