C_7神经根移位重建截瘫大鼠股四头肌功能的实验研究

EXPERIMENTAL RESEARCH ON RECONSTRUCTING QUADRICEPS FEMORIS FUNCTION IN PARAPLEGINA RATS BY C_7 NERVE ROOT TRANSPOSITION

目的 比较应用C7神经根移位加自体、异体神经移植修复重建截瘫大鼠股四头肌功能的疗效。方法取16周龄SPF级雄性Wistar大鼠20只制备冷冻坐骨神经。取14周龄SPF级Wistar雄性大鼠36只,于手术显微镜下,显微剪半横断左侧脊髓造成左侧截瘫模型。建模成功后,随机分A、B组(n=18)。A组通过C7神经根移位将自体同侧坐骨神经桥接股神经根,B组通过C7神经根移位将同种异体冷冻坐骨神经桥接股神经根。两组分别于术后16、24周各取9只行神经电生理检测、大体观察及组织学观察,计算股四头肌湿重恢复率。结果术后16周,A组诱发动作电位幅值(nerve action-evoked potential, NAP)为(1.14±0.07) mV, B组为(0.87±0.06)mV;A组移位神经传导速度(nerve conduction velocity,NCV)为(17.34±2.15)m/s,B组为(11.23±1.45)m/s。术后24周,A组NAP为(1.21±0.07)mV,B组为(0.99±0.05)mV;A组NCV为(19.00±3.02)m/s,B组为(12.54±1.59)m/s。两组各时间点比较差异均有统计学意义(P<0.05)。术后16、24周,HE染色、Bielschowsky嗜银染色均显示A组再生神经纤维数目较多、轴突排列较整齐规则;B组再生神经纤维数目较少,轴突排列分布较零散。术后24周透射电镜观察示两组移植神经内均有大量再生有髓神经纤维及少量无髓神经纤维通过。术后16周,A、B组有髓神经纤维数目分别为(438±79)、(196±31)个/视野,有髓神经纤维面积分别为(5 596.00±583.94)、(4 022.63±615.75)μm2/视野;术后24周,A、B组有髓神经纤维数目分别为(642±64)、(321±75)个/视野,有髓神经纤维面积分别为(6 689.50±1 142.10)、(4 733.00±982.22)μm2/视野:两组比较差异均有统计学意义(P<0.05)。术后16周,A、B组股四头肌湿重恢复率分别为87.96%±4.93%和86.47%±7.47%;术后24周,A、B组分别为90.10%±4.22%和87.66%±3.14%,两组各时间点比较差异均无统计学意义(P>0.05)。 结论 C7神经根移位加自体、异体坐骨神经移植均能重建截瘫大鼠股四头肌部分功能,自体坐骨神经移植组效果明显优于异体坐骨神经移植组。

Objective To observe the resuk of reconstructing quadriceps femoris function in the paraplegia rats by using the 7th cervical nerve root （C7） transposition with autologous and allogeneic neural transplantation. Methods Twenty 16-week-old SPF male Wistar rats were adopted to prepare frozen sciatic nerve. Thirty-six Wistar rats were divided into 2 groups （group A and group B, n=18）. The left paraplegia model was established with left spinal cord hemisection by the micro scissors under the operation microscope. After the model establishment, the homolateral autologous sciatic nerve was bridged with the femoral nerve root by the translocation of C7 in group A, while the allogeneic sciatic nerve was bridged with the femoral nerve root by the translocation of C7 in group B. At 16 weeks and 24 weeks after operation, 9 rats in each group were selected for the neuroelectric-physiological test and then the histomorphology of the nerves was observed under the microscope and the electron microscope. The flesh weight recovery rate ofquadriceps femoris was calculated. Results At 16 and 24 weeks after operation, the nerve action-evoked potential （NAP） was （1.14 ± 0.07） mV and （1.21 ± 0.07） mV in group A, and （0.87 ± 0.06） mV and （0.99 ± 0.05） mV in group B; the nerve conduction velocity （NCV） was （17.34 ± 2.15） m/s and （19.00 ± 3.02） m/s in group A, and （11.23 ± 1.45） m/s and （12.54 ± 1.59） m/s in group B, respectively, indicating significant differences （P 〈 0.05） between 2 groups. At 16 and 24 weeks after operation, HE staining and Bielschowsky staining showed that group A had a large number of nerve fiber regeneration, with a regular arrange of axons; while group B had little nerve fiber regeneration with a scattered arrange of axons. At 24 weeks after operation, images in TEM showed a large number of regeneration myelinated nerve fibers and a small number of unmyelinated nerve fibers through the transplanted nerve in two groups. At 16 weeks after operation, the number of myelinated nerve fibers in group A and group B was （438 ± 79） and （196 ± 31） / vision, the areas of myelinated nerve fibers were （5 596.00 ± 583.94） and （4 022.63 ± 615.75） μm^2 / vision; after 24 weeks, the number of myelinated nerve fibers in groups A and B were （642 ± 64） and （321 ± 75）/vision, the areas of myelinated nerve fibers were （6 689.50 ± 1 142.10） and （ 4 733.00 ± 982.22） μm^2/vision, indicating significant differences between two groups （P 〈 0.05）. There was no statistically significant difference （P 〉 0.05） in the wet weight recovery rate of quadriceps between group A and group B at 16 weeks （87.96% ± 4.93% vs. 86.47% ± 7.47%） and at 24 weeks after operation （90.10% ± 4.22% vs. 87.66% ± 3.14%）. Conclusion C7 transposition combined with autograft and allograft of sciatic nerve can reconstruct the partial function of the quadriceps femoris in paraplegia rats. The effect of graft is better than that of graft obviously.