靶肌肉注射甲钴胺对大鼠周围神经损伤再生的作用

Peripheral nerve regeneration in response to target muscle injection with Methycobal

目的 通过靶肌肉 (腓肠肌 )注射不同剂量的甲钴胺 ,观察其对大鼠坐骨神经损伤的再生作用 ,为临床肌肉局部注射甲钴胺促进周围神经再生探讨较佳的用药剂量和方法。 方法选用健康Wistar大鼠 30只 ,左侧坐骨神经横断后即刻行外膜缝合 ,制备大鼠坐骨神经损伤模型。随机分为A、B、C三组 ,每组 1 0只 ,A组注射甲钴胺 30 0 μg kg,B组注射甲钴胺 1 0 0 μg kg ,C组注射同体积的等渗盐水 1ml,术后靶肌肉注射 1次 d。术后第 4周、第 8周每组分别提取 5只大鼠 ,以左小腿三头肌湿重、光镜和电镜坐骨神经形态学观察并图像分析作为检测指标 ,分析不同剂量甲钴胺对大鼠坐骨神经损伤的影响。 结果 术后 4周左小腿三头肌湿重 ,A组为 (1 .36 7± 0 .0 1 2 )g ,B组为 (1 .1 6 4± 0 .0 1 1 )g,C组为 (0 .95 0± 0 .0 0 9)g ,差异有显著性意义 (P <0 .0 5 ) ;术后 8周 ,A组为 (2 .2 0 5± 0 .0 1 5 )g ,B组为 (1 .6 1 1± 0 .0 1 3)g ,C组为 (1 .2 30± 0 .0 1 4 )g ,差异有显著性意义 (P <0 .0 5 )。术后 4周和 8周行光镜和电镜观察 ,图像分析坐骨神经髓鞘的横截面积、壁厚度 ,A组优于B组 ,B组优于C组。 结论 靶肌肉注射甲钴胺可以促进周围神经的再生 ,高剂量的甲钴胺可以更好地发挥其对损伤神经的营养诱导作用 。

Objective To examine the effect of target muscle injection with different dosages of Methycobal in the sciatic nerve regeneration of adult rats so as to determine a better method and proper dosage of Methycobal for clinical treatment of peripheral nerve injury. Methods A total of 30 healthy Wistar rats were employed to make sciatic nerve injury model through immediate suture of the adventitia posterior to transection of the left sciatic nerve. The rats were divided randomly into three groups, ie, high dosage group (Methycobal for 300 μg/kg, Group A), low dosage group (Methycobal for 100 μg/kg, Group B) and control group (1 ml normal saline once a day, Group C),10 rats in each group. At 4 and 8 weeks, 5 rats from each group were taken to observe the effect of different dosages of Methycobal on rat sciatic nerve regeneration, where the detection indices included morphological changes and image analysis of sciatic nerves by optic and electron microscopic investigations as well as tricipital muscle wet weight. Results Four weeks after operation, tricipital muscle wet weight was (1.367±0.012) g in the Group A, (1.164± 0.011) gin the Group B and (0.950±0.009) g in the Group C, with significant difference among groups A, B and C (P<0.05). Eight weeks after operation, tricipital muscle wet weight was (2.205±0.015) g in the Group A, (1.611±0.013) g in the Group B and (1.230± 0.014) g in the Group C, with significant difference among groups A, B and C (P<0.05). Optic and electron microscopies showed that the transverse area of the sciatic nerve myelin sheath and the wall thickness in Group A was superior to that in Group B that was better than Group C four and eight weeks after operation. Conclusion Target muscle injection with Methycobal is dose-dependent, can promote the peripheral nerve regeneration and worths clinical application.