大鼠水下可控性脊髓爆震伤模型的建立

Establishment of an underwater and controllable spinal cord blast injury rat model

目的摸索爆炸冲击波导致脊髓损伤的超压范围,建立实验室条件下脊髓爆震伤模型,探讨脊髓爆震伤的致伤特点。方法采用10 g的单质锰炸药(RDX)为水下爆源,随机取18只大鼠,通过手术将脊髓暴露后,将大鼠固定于封水仓内,仅椎板切除段脊髓外露于冲击波作用之下,最后按照冲击波到达脊髓表面的超压峰值为10、5、3 MPa分为3组致伤,同时检测冲击波的正压作用时间。另将12只大鼠随机分为致伤组和对照组,致伤组大鼠按照已选定的冲击波超压强度下爆炸致伤,观察伤后全身及脊髓的病理学变化。结果水下爆炸距离0.3、0.8、1.5 m测得的冲击波超压峰值分别为10、5、3 MPa,冲击波超压峰值为3 MPa时可造成大鼠双后肢运动诱发电位(motor evoked potential,MEP)潜伏期延长1.0 ms或波幅下降50%,而不致大鼠死亡。病理学显示脊髓内可见大量散在的出血坏死灶。结论水下爆炸冲击波超压峰值为3 MPa时,能够建立大鼠开放式可控性脊髓爆震伤模型。

Objective To establish an underwater blast injury model of the spinal cord for the study of the overpressure range of blast injury to the spinal cord and its wound characteristics. Methods Eighteen rats were divided into three groups according to the blast overpressure. All the rats underwent laminectomy at the T9 - 10 level. Then the rats were fixed in a capsule and only the exposed spinal cord was ＂affected by shock wave. The explosive device containing 10 g RDX was used to produce blast waves underwater and the blast overpressure was measured at different distance between the explosive device and the exposed surface of the spinal cord. Then an- other 12 rats were divided into two groups. In the injury group, all the rats underwent standard blast injury to the spinal cord, and pathological changes of the spinal cord were observed. Results The overpressure of blast waves was 10, 5, 3 MPa at 0.3, 0.8, 1.5 m, respectively, from the explosive devive. When the overpressure was 3MPa, the blast extended the MEP latent period by 1.0 ms or reduced the amplitude by 10% , while the rats were still alive. Pathological results of the spinal cord revealed a large scattered hemor- rhagic necrosis area, especially in gray matter, and disorganized myelin sheath structure. Conclusions The present experiment dem- onstrates the overpressure range of blast injury to the spinal cord and provides an underwater blast injury model of the spinal cord. The model is simple, safe and effective.