大鼠尺神经功能储备的实验研究

目的 研究尺神经部分束支切取后主干功能变化,提出"周围神经功能储备"的概念,探讨其功能储备量.方法 取3月龄SD大鼠220只,雌雄各半,体重300～350 g.随机分为实验组和对照组(n=110),再根据尺神经切取比例将实验组分为1/8组、1,4组、1/3组、1/2组和2/3组(n=22).根据分组情况,各实验组在10倍手术显微镜下,用微细玻璃针交叉定位的方法切取相应比例尺神经束;对照组于相同平面仅分离神经柬.观察术后大鼠一般情况,于术后1、2周及2个月检测脊髓前角α运动神经元;术后2周,2、3及4个月.行电生理学及支配肌功能学检测.结果 术后大鼠均存活至实验完成,切口无感染,肢端无明显溃疡.各实验组间脊髓前角α运动神经元数量无明显变化(P＞0.05).1/2组和2/3组于术后1周及2周的超微结构变化明显,其他各组变化不明显:术后2个月后各组均恢复正常.术后各时间点,各实验组诱发电位潜伏期与对照组比较,差异均无统计学意义(P＞0.05);各实验组同组术后2、3及4个月诱发电位潜伏期与术后2周比较,差异有统计学意义(P＜0.05),其余各时间点间差异无统计学意义(P＞0.05).术后各时间点,各实验组诱发电位波幅、支配肌最大强直收缩力波幅和持续时间分别与对照组比较,差异均有统计学意义(P＜0.05);各实验组同组术后2、3及4个月分别与术后2周比较,差异有统计学意义(P＜0.05);其余各时间点间差异无统计学意义(P＞0.05).结论 尺神经功能良好代偿的功能储备量为其主干直径的1/3.

EXPERIMENTAL STUDY ON THE FUNCTIONAL RESERVE OF ULNAR NERVE IN RATS

OBJECTIVE: To study the functional change of nerve trunk after removing the partial bundles of ulnar nerve, to propose the concept of functional reserve of peripheral nerves and to investigate the functional reserve quantity of peripheral nerves. METHODS: Two hundred and twenty SD rats (male or female), aging 3 months and weighing 300-350 g, were randomized into the experimental group and the control group (n=110 per group). And the experimental group was subdivided into group 1/8, group 1/4, group 1/3, group 1/2 and group 2/3 according to the resection portion (n=22 per group). In the experimental group, the section of the lowest level on ulnar nerve trunks was exposed, and a certain portion of its bundles was separated and cut, while in the control group the bundles were only separated without resection. The general condition of all rats was observed, and the motoneurons in cornu anterius medullae spinalis were detected at 1 week, 2 weeks and 2 months after operation. The neuro-electrophysiology and the function of dominated muscles were detected at 2 weeks, 2 months, 3 months, and 4 months after operation. RESULTS: All the rats survived without infection and obvious ulcer in the limbs. The number of motoneurons in cornu anterius medullae spinalis in various experimental subgroups witnessed no obvious changes (P > 0.05). The superstructure changed obviously at the early postoperative stage in group 1/2 and group 2/3, but restored well at 2 months after operation. For the latent period of evoked potential, there was no significant difference between the various experimental subgroups and the control group at each time point (P > 0.05), but there was a significant difference among the various experimental subgroups when compared the time points of 2, 3 and 4 months to that of 2 weeks (P < 0.05) and no statistically significant difference at other time points (P > 0.05). For the wave amplitude of evoked potential of motor nerves, the maximum wave amplitude and the persistence time of the dominate muscle, there were significant differences between the various experimental subgroups and the control group at each time point (P < 0.05), and there were significant differences among the various experimental subgroups when comparing the time points of 2, 3 and 4 months to that of 2 weeks (P < 0.05) and no statistical significance at other time points (P > 0.05). CONCLUSION: The functional reserve of the ulnar nerve without compromise accounts the 1/3 of the whole trunk diameter.