Objective Aminoguanidine (AG) can reduce brain edema and increase the recovery of neuron functions in surgical brain injury and stroke. To investigate the effect of AG on spinal cord injury (SCI) in rats and its mechanism. Methods A total of 150 adult male Sprague Dawley rats (weighing, 230-255 g) were divided into control group (group A, 25 rats without treatment), the sham-operated group (group B, 25 rats undergoing laminectomy), SCI group (group C, 25 SCI rats with injection of 5%DMSO), SCI + AG groups (groups D, E, and F, 25 SCI rats and AG injection of 75, 150, and 300 mg/kg, respectively). The optimal dosage of AG was screened by dry-wet weight method with the percentage of water content at 0, 12, 24, and 48 hours after injury. The blood-spinal cord barriar permeability was further detected by Evans blue (EB) method, aquaporins 4 (AQP4) mRNA expression by RT-PCR, AQP4 protein expression by immunohistochemistry and Western blot. Results AG injection at dosage of 150 mg/kg can significantly reduce edema of spinal cords at 12, 24, and 48 hours after SCI (P lt; 0.05), so 150 mg/kg was the optimal dosage. The EB content in group E was significantly lower than that in group C at 12, 24, and 48 hours after SCI, and the permeability of blood-spinal cord barrier was significantly decreased compared with group C (P lt; 0.05). The AQP4 mRNA expressions in groups B and E were significantly lower than that in group C at 12, 24, and 48 hours after SCI (P lt; 0.05). AQP4 protein expressions in groups B and E were significantly lower than that in group C at 24 and 48 hours after SCI (P lt; 0.05) by Western blot. Immunohistochemical staining revealed that AQP4 protein expression in group C was significantly higher than that in groups B and E (P lt; 0.05) at 48 hours after SCI, but no significant difference was found between group B and group E (P gt; 0.05). Conclusion AG injection at dosage of 150 mg/kg can induce spinal cord edema and injury in rats, which could be correlated with the down-regulation of AQP4 expression.
Objective To investigate tissue engineered spinal cord which was constructed of bone marrow mesenchymal stem cells (BMSCs) seeded on the chitosan-alginate scaffolds bridging the both stumps of hemi-transection spinal cord injury (SCI) in rats to repair the acute SCI. Methods BMSCs were separated and cultured from adult male SD rat. Chitosan-alginate scaffold was produced via freeze drying, of which the structure was observed by scanning electron microscope (SEM) and the toxicity was determined through leaching l iquor test. Tissue engineered spinal cord was constructed by seeding second passage BMSCs on the chitosan-alginate scaffolds (1 × 106/mL) in vitro and its biocompatibil ity was observed under SEM at 1, 3, and 5 days. Moreover, 40 adult female SD rats were made SCI models by hemi-transecting at T9 level, and were randomly divided into 4 groups (each group, n=10). Tissue engineered spinal cord or chitosan-alginate scaffolds or BMSCs were implanted in groups A, B, and C, respectively. Group D was blank control whose spinal dura mater was sutured directly. After 1, 2, 4, and 6 weeks of surgery, the functional recovery of the hindl imbs was evaluated by the Basso-Beattie-Bresnahan (BBB) locomotor rating score. Other indexes were tested by wheat germ agglutinin-horseradish peroxidase (WGA-HRP) retrograde tracing, HE staining and immunofluorescence staining after 6 weeks of surgery. Results Chitosan-alginate scaffold showed three-dimensional porous sponge structure under SEM. The cells adhered to and grew on the surface of scaffold, arranging in a directional manner after 3 days of co-culture. The cytotoxicity of chitosan-alginate scaffold was in grade 0-1. At 2, 4, and 6 weeks after operation, the BBB score was higher in group A than in other groups and was lower in group D than in other groups; showing significant differences (P lt; 0.05). At 4 and 6 weeks, the BBB score was higher in group B than in group C (P lt; 0.05). After 6 weeks of operation, WGA-HRP retrograde tracing indicated that there was no regenerated nerve fiber through the both stumps of SCI in each group. HE and immunofluorescence staining revealed that host spinal cord and tissue engineering spinal cord l inked much compactly, no scar tissue grew, and a large number of neurofilament 200 (NF-200) positive fibers and neuron specitic enolase (NSE) positive cells were detected in the lesioned area in group A. In group B, a small quantity of scar tissue intruded into non-degradative chitosan-alginate scaffold at the lesion area edge, and a few of NSE flourescence or NF-200 flourescence was observed at the junctional zone. The both stumps of SCI in group C or group D were filled with a large number of scar tissue, and NSE positive cells or NF-200 positive cells were not detected. Otherwise, there were obviously porosis at the SCI of group D. Conclusion The tissue engineered spinal cord constructed by multi-channel chitosan-alginate bioscaffolds and BMSCs would repair the acute SCI of rat. It would be widely appl ied as the matrix material in the future.
Objective To investigate the effect of methylprednisolone sodium succinate (MP) and mouse nerve growth factor (mNGF) for injection in treating acute spinal cord injury (ASCI) and cauda equina injury. Methods Between December 2004 and December 2007, 43 patients with ASCI and cauda equina injury were treated, including 33 males and 10 females with an average age of 43 years (range, 32-66 years). Injured vertebral columns were C2 in 1 case, C4 in 5 cases, C5 in 7cases, C6 in 3 cases, T8 in 1 case, T10 in 1 case, T11 in 2 cases, T12 in 3 cases, L1 in 9 cases, L2 in 5 cases, L3 in 3 cases, L4 in 1 case, and L5 in 2 cases. All the patients had sensory disturbance and motor dysfunction at admission. The Frankel scale was used for assessment of nerve function, 5 cases were rated as Grade A, 12 as Grade B, 22 as Grade C, and 4 as Grade D before operation. In 43 patients, 23 cases were treated with MP and mNGF (group A), 20 cases with MP only (group B). There was no significant difference in general data between 2 groups (P gt; 0.05). All the patients were admitted, received drug treatment within 8 hours of injury, and were given spinal canal decompression, bone transplantation, and internal fixation within 48 hours. The neurological function score systems of American Spinal Injury Association (ASIA) were used for neurological scores before treament, at 1 week and 2 years after treatment. The scores of the activity of daily l iving (ADL) were evaluated and compared. Results All the patients achieved heal ing of incision by first intention. Forty-three cases were followed up 24-61 months with an average of 30 months. Bone graft fusion was achieved after 6-17 months, 11 months on average with stable fixation. No death and compl ications of osteonecrosis and central obesity occurred. There was no significant difference in neurological function scores and ADL scores between 2 groups before treatment (P gt; 0.05); however, the neurological function scores and ADL scores at 1 week and 2 years after treatment were higher than those before treatment (P lt; 0.01) in 2 groups. Group A had higher neurological function scores and ADL scores than group B (P lt; 0.01). At 1 week and 2 years after treatment, the improvement rates of neurological function of group A (47.8%, 11/23 and 91.3%, 21/23) were significantly higher (P lt; 0.01) than those of group B (30.0%, 6/20 and 70.0%, 14/20). Conclusion MP and mNGF play an important role in improving the neurological function in patients with ASCI and cauda equina injury.