成年小鼠颈5脊髓钳夹损伤模型的制备与评价

Establishment and evaluation of C5 dorsal spinal cord crush injury model in adult mice

中文关键词:  脊髓损伤  小鼠  轴突再生  模型

英文关键词:Spinal cord injury  Mice  Axon regeneration  Model

中文摘要:

  【摘要】 目的：制备小鼠C5脊髓背侧及背外侧束钳夹损伤模型，评价损伤后动物的行为学和组织学表现。方法：采用C57/BL成年小鼠为实验对象，将16只动物随机分为损伤组和对照组，每组8只。动物麻醉后，切开背侧颈部皮肤，显露并切除小鼠C5椎板，损伤组采用自制改良FST DUMONT 5号手术钳分别钳夹背侧皮质脊髓束（dCST）和脊髓背外侧束两次；对照组仅切除椎板不做脊髓钳夹损伤。分别在术前和术后3d、2周、4周、6周、8周时采用圆筒实验、水平楼梯实验和食物抓取实验评价动物的行为学表现；术后８周时采用BDA顺行示踪观察皮质脊髓束（CST）和红核脊髓束（RST）在损伤后的情况。结果：钳夹损伤后，小鼠后肢步行功能正常但肢体的精细活动能力受到明显影响。在圆筒实验中，损伤组小鼠伤侧前肢的使用频率下降，前肢梳洗动作幅度受限，伤后各时间点与对照组相比差异均有统计学意义（P<0.05）；在水平楼梯实验中，损伤组小鼠对横梁的抓握精确性降低，伤后各时间点与对照组相比差异有统计学意义（P<0.05）；在食物抓取实验中，损伤组小鼠的食物抓取能力也出现了明显受限，伤后各时间点与对照组相比差异有统计学意义（P<0.05）。以上行为学结果在伤后3d达高峰，2周后逐渐恢复，但直至8周仍不达正常水平。术后８周顺行示踪结果显示对照组小鼠CST和RST均显露清晰，纤维束呈纵行排列；损伤组小鼠CST和RST在损伤处大量断裂、逆向崩解，且无再生迹象。结论：成年小鼠C5脊髓钳夹损伤模型能够方便观察动物随意运动的控制情况及评价轴突的再生状况，适合作为轴突再生的研究模型。

英文摘要:

  【Abstract】 Objectives: To evaluate the C5 spinal cord crush injury(SCI)　model by behavior performance and histology in adult mice. Methods: A total of 16 adult mice(C57/Black) was randomly assigned into two groups, SCI group and Sham group with eight mice in each group. The spinal cord crush injury(the dorsal and dorsal lateral axons were cut) model at C5 was established by using a modified FST DUMONT 5 surgical forceps. In the Sham group, the lamina was removed without damaging the spinal cord. The behavior performance was evaluated by rearing cylinder, horizontal ladder, and stair case pellet reaching. The axons of the corticospinal tract(CST) and the rubrospinal tract(RST) were observed 8 weeks after operation by using BDA anterograde tracing. Results: The hind limb locomotor function was rarely affected in both groups and showed similar BMS scores after injury. However, the fine skilled motor functions were obviously impaired by this axonal crush. Specifically, animals in the SCI group showed significant decrease of the upper limbs usage on the injured side and the limitation of grooming actions in the rearing cylinder, when compared with the Sham group at all time points（P<0.05）. Similarly, when walking across the horizontal ladder, mice in the SCI group showed significant accuracy reduction in gripping the beam, especially in the injured side, when compared with the Sham group at all time points(P<0.05). The ability of grasping food pellets in the SCI group significantly decreased when compared with the Sham group at all time points(P<0.05). These impaired motor functions reached the summit 3 days after injury and started to recover 2 weeks later. However, they did not go back to normal even 8 weeks after injury. No regeneration was observed neither in the corticospinal tract nor in the rubrospinal tract 8 weeks after injury. Conclusions: A stable, reliable and clinical relevant animal model of cervical spinal cord injury was successfully established, which was suitable for axon regeneration researches.