| Objective:To observe the effect on proliferation and differentiation of endogenous neural stem cells and function recover after the spinal cord injury (SCI) treated with Simvastatin in rats. Methods:60 healthy female SD rats were subjected to weight-drop impact causing complete paraplegia at T9-10 level and were randomly divided into three groups (20 rats in each group).5mg/kg,10mg/kg simvastatin and physiological saline was injected into abdominal cavity respectively at the same time from the surgery day to the next 7 days. The Sham group, as group D, only underwent laminectomy at T9 level without spinal cord injury. The BBB scale were evaluated at the day before surgery and at 7,14,21 and 28 days after surgery respectively. The sensory evoked potential (SEP) was monitored at 7,14,21 and 28 days after SCI respectively. Neurons and astrocytes were observed by HE staining at 7,14,21 and 28 days after SCI and the expression of GFAP and NF200 were observed and calculated by immunohistochemical staining at 28 day respectively. All of the value were documented by x SD and analyzed with SPSS 11.5 software.Results:The BBB scale was 7.68±1.83 in group A,7.72±1.11 in group B,7.24±0.79 in group C,21 in group D at 7d after surgery respectively and there was no difference among of it in group A,B,C.It was 9.49±1.29 in group A,9.81 ±0.98 in group B,9.15±0.79 in group C,21 in group D at 14d after surgery respectively and there was no difference among of it in group A,B and C. It was 13.53±1.24 in group A,14.01±0.87 in group B,10.76±0.88 in group C,21 in group D at 21d after surgery respectively. It in group A or B were higher than it in group C and there was no difference between it in group A and B.It was 15.21±0.91 in group A,15.01±1.01 in group B,11.03±0.46 in group C, 21 in group D at 28d after surgery respectively. It in group A or B were higher than it in group C and there was no difference between it in group A and B. There was no difference in the value of group D at each time point. The latency of SEP was 36.68±3.52 in group A,35.23±3.14 in group B,36.42±3.35 in group C,14.46±4.31 in group D at 7d after surgery respectively and there was no difference among of it group A,B and C. It was 30.62±2.74 in group A,30.24±4.01 in group B,31.36±3.99 in group C,17.02±3.56 in group D at 14d after surgery respectively and there was no difference among of it group A,B and C. It was 23.32±3.97 in group A,22.61±2.54 in group B,30.74±2.95 in group C,15.64±2.54 in group D at 21 d after surgery respectively and the value in group A,B was significant lower than it in group C,but there was no obvious difference between A and B. It was 18.25±4.12 in group A,17.56±3.44 in group B,27.94±4.16 in group C,14.74±2.47 in group D at 28d after surgery respectively. The value in group A,B was lower than it in group C and there was no obvious difference between group A and B. Group D had a shorter latency at each time point.The wave amplitude of SEPs was 2.06±0.27 in group A,2.12±0.11 in group B,1.76±0.13 in group C,15.67±1.88 in group D at 7d after surgery respectively and there was no difference among of it in group A, B and C.It was 2.25±0.31 in group A,2.45±0.27 in group B,1.85±0.58 in group C,16.28±2.34 in group D at 14d after surgery respectively and there was no difference among of it group A,B and C. It was 5.87±1.38 in group A,6.02±1.13 in group B, 2.08±0.47 in group C,16.08±1.78 in group D at 21d after surgery respectively.The amplitude in group A and group B was higher than it in group C and there was no obvious difference in group A, B. It was 6.12±0.98 in group A,6.73±1.56 in group B,2.14±0.57 in group C,16.32±1.44 in group D at 28d after surgery respectively.It in group A and B were higher than it in group C and there was no obvious difference between group A and B. HE staining showed the loss of neuron in group C was more obvious compared with it in group A and B. The proportion of gray cavity was big compared with it in group A and B and infiltration of the inflammatory cells was significantly higher in group C at 7d after surgery. The formation of glial scar were more apparent and the rate of inflammatory cells was fewer in groug C compared with it in group A or B at 14,21,28d after surgery respectively. The number of neurons in group A and B was higher compared with it in group C. The expression of NF200 was 2171.32±187.3 in group A,2201.46±165.5 in group B,1661.04±146.2 in group C,3351±121.3 in group D at 28 d after surgery respectively and there were more expression of NF200 in group A or B compared with it in group C. The expression of GFAP was 2127.46±141.7 in group A,2061.19±152.5 in group B,3351.13±156.8 in group C,1732.46±149.4 in group D and it was higher in group C compared with it in group A or B at 28d after surgery.There was no difference about the expression of NF200 and GFAP between it in group A and B at 28d after surgery. Conclusion:Simvastatin can promote recovery of motor function, reduce inflammatory cell infiltration, inhibit endogenous neural stem cells differentiation into astrocytes after spinal cord injury in rats. The effect of 10mg/kg simvastatin is stronger compared with it of 5mg/kg, but there was no statistical difference. |
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