RESUMEN
OBJECTIVE: To explore the effects of Neurogenesin 1 (Ng1) gene on functional recovery after spinal cord injury (SCI) and its mechanism. METHODS: Thirty-six rats (aging 4 months, weighing 230 g and being male or female), were randomly divided into two groups: experimental group (n=18) and control group (n=18). After spinal cord contusive injury at T10 level was made in all these rats using modified Allen's method, Ng1 recombinant plasmid and blank plasmid were transfected into the damaged areas of experimental group and control group respectively by Alzet pumps. At 1 day, 1 week, 2 weeks, 3 weeks, and 4 weeks after SCI, Basso-Beattle-Bresnahan (BBB) Rating Scale was used to observe the recovery of motor function. At 1 week after injury, the expressions of Ng1 mRNA and protein in injured spinal cord were detected by RT-PCR and Western blot techniques. And at 2 and 4 weeks, double immunofluorescence and histopathologic examinations were performed to study the proliferation of the adult endogenous neural stem cells and pathological change after SCI. RESULTS: At 1-4 weeks after SCI, the BBB scores in the experimental group was significantly higher than that in control group (P < 0.05), and at 4 weeks the BBB score of the experimental group (16.80 +/- 1.79) was significantly higher than that of the control group (9.60 +/- 1.67), (P < 0.01). RT-PCR and Western blot showed that the mRNA and protein expressions of Ng1 were observed in the experimental group and no expression was seen in the control group. Histologic observation showed that the morphology of spinal cord and neurons in the experimental group was better than that in the control group and was close to the normal tissue. The mean number of Nestin+/BrdU+ newborn endogenous neural stem cells in the experimental group was significantly more than that in control group (P < 0.05). CONCLUSION: Ng1 gene could promote the proliferation of endogenous neural stem cells and protect the injured neurons, which enhances the repair of the motor function after SCI.
