一氧化氮合酶活性的变化对大鼠脊髓继发性损害的影响

目的观察一氧化氮含量的变化对脊髓继发性损害的影响。方法采用闭合性液压损伤装置致大鼠脊髓（Ｔ９）中度损伤,分别静脉注射生理盐水及不同剂量的一氧化氮合酶抑制剂Ｌ－ＮＡＭＥ（８ｍｇ／ｋｇ,４０ｍｇ／ｋｇ）。观察对血流动力学、局部组织结构、神经电生理、神经行为学的影响。结果发现小剂量Ｌ－ＮＡＭＥ对大鼠全身血流动力学影响不大,组织破坏较轻,可促进神经功能恢复;大剂量Ｌ－ＮＡＭＥ明显升高平均动脉压、收缩软脊膜小动脉（９０分钟、直径减少１０％）、减少局部血流量（９０分钟、减少２２％）、增加局部组织损害,神经功能障碍不能恢复、甚至加重,体重进行性减轻,死亡率增加。结论表明一氧化氮在继发性脊髓损伤中,小剂量的一氧化氮可能起到保护作用,但过量时又可起到破坏作用。

The effects of nitric oxide synthase on secondary spinal cord injury: an experimental research

Objectives To investigate the effects of the changing amount of nitric oxide on secondary spinal cord injury and determine the role of nitric oxide during secondary spinal cord injury. Methods After close spinal cord modest injury (T 9) by fluid percussion model, rats were given saline, small dose of L NAME (8 mg/kg) and large dose of L NAME (40 mg/kg) respectively. The changes of hemodynamics, tissue constitution, and neural function were observed. Results We found small dose of L NAME had little effects on the hemodynamics but could improve neural function. Whereas, large dose of L NAME raised the MABP significantly, constricted pial arteriole (90 minutes, 10%), decreased regional spinal cord blood flow (SCBF) (90 minutes, 22%), augmented the dysfunction of neural system. Rats lost weight and the rate of death raised. Conclusions These findings indicated that nitric oxide could have dual role during secondary spinal cord injury. Controlling local nitric oxide production suitably through changing the activity of nitric oxide synthase could improve tissue survival and benefit the recovery of neural function.