施万细胞和一氧化氮合酶抑制剂对大鼠脊髓损伤后背核神经元存活及其轴突再生的影响

目的探讨施万细胞(SCs)和一氧化氮合酶(NOS)抑制剂L-NNA联合应用能否促进脊髓损伤后背核神经元存活及其轴突再生。方法20只成年大鼠分为对照组、SCs组、L-NNA组和SCs L-NNA组。在SCs L-NNA组动物T11脊髓段半横断后在损伤处植入施万细胞，术后腹腔内注射L-NNA。结果脊髓半横断后30d，对照组L1脊髓段损伤侧背核神经元数量减少，其胞体皱缩，NOS表达阳性。SCs组存活的神经元增加的同时其NOS表达增强，胞体也发生皱缩。L-NNA组和SCs L-NNA组存活的神经元也增加，但NOS表达降低，其胞体皱缩得到改善。各组中仅在SCs L-NNA组L1脊髓损伤侧背核观察到有被FG标记的神经元胞体，提示其再生轴突穿越损伤区到达头端脊髓组织。结论SCs和L-NNA都可促进脊髓半横断背核受损伤神经元的存活；两者联合应用能更好地促进受损伤背核神经元存活及其轴突再生。

EFFECTS OF SCHWANN CELLS AND L-NNA OF THE NEURONAL SURVIVAL AND AXONAL REGENERATION IN CLARKE'S NUCLEUS AFTER RAT SPINAL CORD INJURY

Objective Whether combination of Schwann cells(SCs) and LNNA(nitric oxide synthase,NOS inhibitor) could promote the neuronal survival and axonal regeneration in Clarke's nucleus (CN) following spinal cord hemisection (SCH) was explored. Methods Twenty adult female rats were divided into control group, SCs group, LNNA group and SCs+LNNA group. SCs were immediately implanted into the lesioned site after hemisection of T11 spinal cord segment and L-NNA was intraperitoneally injected in SCs+LNNA group. Results Thirty days after spinal cord hemisection, the number of CN surviving neurons and the area of CN neuronal soma on lesioned side of L1 spinal cord decreased significantly in control group. The activity of NOS was detected in some surviving neurons. The number of CN surviving neurons on lesioned side of L1 spinal cord increased in SCs group and LNNA group. In SCs group, the number of the NOS positive neurons was increased, while the soma area was still shrinkage. In LNNA group, the number of NOS positive neurons was decreased and the soma area was increased. In SCs+LNNA group, the number of CN surviving neurons and the mean soma area were significantly increased on lesioned side, and NOS activity of surviving neurons was depressed. Among all groups of rat, that some CN surviving neurons on lesioned side of L1 spinal cord were retrogradely labeled with fluorogold was observed only in SCs+LNNA group. It suggested that their axons have regenerated into the cranial spinal cord through lesioned area.Conclusion SCs or LNNA may promote the CN lesioned neuronal survival after spinal cord hemisection. Combination of SCs and LNNA may significantly enhance not only the CN lesioned neuronal survival, but also the axonal regeneration.;