大鼠脊髓损伤后大脑运动皮质神经元凋亡的观察

Apoptosis of neuron in cerebral motor cortex after spinal cord injury in rat

中文关键词:  脊髓损伤  神经元  凋亡  运动皮质  大鼠

英文关键词:Spinal cord injury  Neuron  Apoptosis  Motor cortex  Rat

中文摘要:

  【摘要】 目的：观察大鼠脊髓损伤后大脑运动皮质神经元的凋亡情况，探讨其相关因素。方法：SD大鼠72只，随机分为3组：阴性对照组（正常大鼠）、假手术组（单纯椎板切除）、脊髓损伤组（椎板切除+脊髓横断损伤），每组24只,各组分别于造模后1d、3d、7d、14d处死6只动物取材。应用原位末端标记法（TUNEL法）对脊髓损伤后大脑运动皮质区行神经元凋亡检查，并检测该区域神经元诱生型一氧化氮合酶（iNOS）的表达情况，分析神经元凋亡与iNOS表达的关系。结果：脊髓损伤组大鼠大脑运动皮质区神经元在术后1d、3d、7d、14d的凋亡指数分别为（10.11±4.02）%、（56.53±8.63）%、（35.03±11.66）%、（3.78±1.03）%，均高于相应时间点阴性对照组和假手术组 （P<0.05），术后3d凋亡指数显著高于术后1d、7d和14d（P<0.01）。术后1d、3d、7d、14d脊髓损伤组大鼠大脑运动皮质iNOS阳性神经元百分数分别为（17.92±2.75）%、（60.65±8.78）%、（34.35±7.74）%、（6.12±1.99）%，1d、3d、7d时均高于相应时间点阴性对照组和假手术组（P<0.05），14d时三组间无显著性差异；脊髓损伤组术后3d时显著高于其余时间点（P<0.01）。脊髓损伤组大鼠大脑运动皮质区神经元凋亡指数与iNOS阳性神经元百分数之间存在显著性正相关关系（r=0.89，P<0.01）。结论：大鼠脊髓损伤后大脑运动皮质区神经元凋亡增加，其可能与iNOS的表达增加有关。

英文摘要:

  【Abstract】 Objectives: To investigate the apoptosis of neuron in cerebral motor cortex after spinal cord injury(SCI) in rat. Methods: Seventy-two SD rats were divided into 3 groups randomly as follows: control group(intact), sham-operation group(laminectomy only) and SCI group(laminectomy and spinal cord transection injury at T10). There were 24 rats in each group. Six rats in each group were sacrificed respectively on the 1st day, 3rd day, 7th day and 14th day after operation. TUNEL was applied to detect apoptosis of neurons in motor cortex after spinal cord injury. Expression of iNOS of neurons in the same area was also investigated. Then the relationship of apoptosis and expression of iNOS of neurons in motor cortex was analyzed. Results： Apoptosis index（AI） of SCI group was (10.11±4.02)%, (56.53±8.63)%, (35.03±11.66)%, (3.78±1.03)% on the 1st day, 3rd day, 7th day and 14th day after SCI respectively, which was higher than that of control group and sham-operation group(P<0.05). Compared with the other time points(the 1st day,7th day and 14th day), AI on the 3rd day was higher(P<0.01) in SCI group. Percentage of iNOS positive neurons on the 1st day, 3rd day, 7th day and 14th day in SCI group was (17.92±2.75)%, (60.65±8.78)%, (34.35±7.74)%, (6.12±1.99)% respectively. On the 1st day, 3rd day, 7th day, percentage of iNOS positive neurons in SCI group was higher than that of control group and sham-operation group(P<0.05) respectively. But there was no significant difference among the 3 groups on the 14th day. Compared with the other time point, percentage of iNOS positive neurons on the 3rd day was higher in SCI group(P<0.01). AI showed positive correlation with percentage of iNOS positive neurons in SCI group(r=0.89, P<0.01). Conclusions: Apoptosis of neuron in cerebral motor cortex increases after SCI in rat. After SCI, which may be related with the increased expression of iNOS.