摘要
目的以小鼠作为实验动物,采用改良垂直打击脊髓(weight dropping,WD)建立脊髓损伤(spinal cord injury,SCI)动物模型,为进一步研究SCI机制奠定基础。方法将健康雌性昆明种小鼠180只随机分为4组,每组45只,采用改良WD法应用Impactor model-Ⅱ脊髓致伤仪分别以2.0×2.5g.cm(A组)、2.5×3.0g.cm(B组)、3.0×5.0g.cm(C组)致伤力致伤脊髓;对照组(D组)仅打开椎板,暴露脊髓,不造成SCI。于打击后即刻,6、12h,1、3d,1、2、4、8周对各组小鼠行运动诱发电位(motor evoked potentials,MEP)检测,并行后肢运动功能(Basso mouse scale,BMS)评分,HE染色和甲苯胺蓝染色组织学观察。结果神经电生理检查示B组于伤后6h,C组于伤后12h出现N1潜伏期延长,随着时间延长,A、B、C3组潜伏期开始缩短,A组4周趋于正常为(2.40±0.12)ms,与D组比较差异无统计学意义(P>0.05);B组8周逐渐趋于正常为(2.96±0.15)ms,与D组比较差异无统计学意义(P>0.05),而C组8周仍维持在较高水平(3.76±0.13)ms,与D组比较差异有统计学意义(P<0.05)。SCI伤后即刻小鼠均呈现双后肢瘫痪,BMS主评分为0分;伤后前3dBMS主评分接近0分;随后各组BMS评分逐渐上升,A组伤后1周BMS主评分(5.45±0.12)分,B组伤后2周BMS主评分为(5.45±0.15)分,与D组比较差异均有统计学意义(P<0.05);伤后8周A组主评分(8.00±0.13)分,B组达(7.50±0.31)分;1周后各实验组组间比较差异均有统计学意义(P<0.05),其中C组低于其余各组(P<0.01)。伤后2周A组BMS副评分为(10.12±0.76)分,伤后8周B组BMS副评分为(9.85±0.55)分,与同时间点D组比较差异均无统计学意义(P>0.05)。组织学检查可见C组伤后12h,损伤节段灰质内大片出血灶,炎性细胞浸润,神经元细胞肿胀明显,并出现中央性尼氏小体溶解;随时间推移,神经元细胞数量减少,胶质细胞增生,尼氏小体消失;伤后2周,可见大量胶质细胞增生及空洞形成。B组神经元细胞减少程度及空洞形成均轻于C组,A组最轻,D组除早期可见轻度细胞水肿外,整个观察期内细胞数量无明显改变。结论该模型准确地反映了小鼠脊髓不同程度损伤后的病理生理特点及变化规律,重复性好;可采用重物打击法制作标准小鼠SCI动物模型。
Objective To make a mouse model of traumatic spinal cord injury （SCI） by Allen＇s weight dropping （WD）, which might be helpful for further research on the mechanism of SCI. Methods A total of 180 healthy female mice, weighing 17 - 23 g （20 g on average）, were randomized into 4 groups （n=45 per group）： the experimental groups of A, B and C and the control group of D. Experimental groups were distinguished by the amount of weight or the height from which the weight was dropped onto an impounder resting on the dura （2.0 × 2.5 g.cm, 2.5 × 3.0 g＇cm, 3.0 × 5.0 g＇cm）. In group D, neural scute was opened only and spinal cord was exposed without SCI. The recovery of the lower extremity was observed at various time points （0, 6 and 12 hours, 1 and 3 days, 1, 2, 4 and 8 weeks） by using the Basso mouse scale （BMS） scoring system, motor evoked potentials （MEP） and histological observation. Results MEP displayed that the incubation period of N1 wave was extended in group B after 6 hours and in group C after 12 hours. As time passed by, the incubation periods of N1 wave in group A, group B and group C began to shorten. The incubation period in group A was close to normal at 4 weeks （2.40 ± 0.12） ms, and there was no significant difference compared with group D （P 〉 0.05）. The incubation period in group B was close to normal at 8 weeks （2.96 ± 0.15） ms, and there was no significant difference compared with group D （P 〉 0.05）. The incubation period in group C was still relatively high at 8 weeks （3.76 ± 0.13） ms, and there was a significant difference compared with group D （P 〈 0.05）. Both hind limbs of all mice were paralytic instantly after SCI, the score of main BMS was 0 point; the score of main BMS was close to 0 at the first 3 days after SCI, the score of main BMS of group A was 8.00 ± 0.13 and group B was 7.50 ± 0.31 at 8 weeks; the score of main BMS of group A was 5.45 ± 0.12 at 1 week and group B was 5.45 ± 0.15 at 2 weeks which were significantdifference compared with group D （P 〈 0.05）.There were significant differences among groups A, B and C after 1 week ofSCI （P 〈 0.05）, and group C was lower than the others（P 〈 0.01）. The score of adjuvant BMS of group A was 10.12 ± 0.76 at 2 weeks and group B was 9.85 ± 0.55 at 8 weeks which was no significant difference compared with the group D at the same time （P 〉 0.05）. Histological observation showed hemorrhage, cellular edema, inflammatory cell infiltration, nerve cell swell and solution of Nissl body 12 hours after SCI in group C. As time passed by, the number of nerve cells decreased, the glial cell proliferated and Nissl body vanished. There was much glial cell proliferation and cavitation 2 weeks after SCI in group C. The nerve cell decrease and cavitation in group B was slighter than that in group C, and group A was the slightest. In group D, there was no obvious change of the number of cells during the observation apart from slight edema in early period. Conclusion The mouse model precisely reflects the pathological and physiological features and law of change after different degrees of SCI, and can be used as a standard of mouse model of traumatic SCI by Allen＇s WD.
出处
《中国修复重建外科杂志》
CAS
CSCD
北大核心
2008年第8期933-938,共6页
Chinese Journal of Reparative and Reconstructive Surgery
基金
国家自然科学基金资助项目(30500512)~~
关键词
脊髓损伤
动物模型
脊髓打击设备
小鼠
Spinal cord injury Animal model Spinal cord contusion system Mouse
