Wnt4、Wnt7a在不同程度脊髓损伤小鼠中的差异表达

【目的】观察非经典Wnt信号通路相关基因、平面细胞极性（PCP）相关基因在不同程度脊髓损伤（SCI）后的表达变化。【方法】采用LISA脊髓撞击器构建小鼠脊髓损伤模型，实验分为SCI0.65组（损伤深度为0.65mm）、SCI0.45组（损伤深度为0.45mm）和Sham组（假手术）；通过BMS评分和CatWalk9.0步态分析系统测试小鼠术后运动功能；应用VonFrey纤毛和冷热板检测小鼠术后神经病理性疼痛；利用Real-time PCR法检测小鼠脊髓损伤节段和腰4腰5（L4-5）节段非经典Wnt信号通路相关基因和PCP相关基因的表达变化。【结果】①在损伤后第7、10、25、42天，SCI0.65组BMS评分明显低于SCI0.45组（P<0.05）；CatWalk9.0步态分析结果表明SCI后损伤组小鼠四肢协调率低于Sham组（P<0.01）。②脊髓损伤后第28天损伤组小鼠均出现机械性痛觉超敏并且持续至42d，且损伤程度越重，机械性痛阈值越低（P<0.001）；脊髓损伤后小鼠冷热痛异常，但是与损伤程度无关。③脊髓损伤造模后42d，SCI0.45组和Sham组小鼠脊髓组织中Wnt4与Wnt7a表达无显著变化，SCI0.65组Wnt4表达上调、Wnt7a表达下调（P<0.05）。【结论】①小鼠SCI后产生神经病理性疼痛。不同程度的脊髓损伤对机械痛表现出不同的敏感性。②Wnt4和Wnt7a的表达变化提示它们可能在脊髓损伤后运动神经回路的可塑性中起重要作用。

Differential Expression of Wnt4 and Wnt7a in Mice with Different Degrees of Spinal Cord Injury

【Objective】To investigate the changes of Non- canonical Wnt signaling pathway and planar cell polarity（PCP）related genes by different degrees of spinal cord injury（SCI）in mice.【Methods】SCI model was established by hitting T10 spinal cord with Louisville Injury System Apparatus （LISA）. The mice were randomly divided into three groups：sham group，SCI groups with spinal cord displacement of 0.45 mm（SCI 0.45 group）and 0.65 mm（SCI 0.65 group）.Locomotor function was assessed with CatWalk 9.0 apparatusbased on the Basso mouse scale（BMS）. Neuropathic pain after SCI were measured by Von Frey filament and Cold Hot plate. The expression of Non- canonical Wnt signaling pathway and planar cell polarity related genes at the injury site and lumbar 4-5（L4-5）was examined by Real-time PCR after behavior tests.【Results】① The hindlimb BMS score were lower at days from post-injury day（dpi）7，10，25 and 42 in SCI 0.65 group compared with SCI 0.45 group（P < 0.05）. Gait analysis showed limb coordination in both injured groups was worse than that of sham group（P < 0.01）. ② After SCI was stimulated by Von Frey filament，the number of withdrawals increased with time ，and the withdrawal threshold decreased with time （P < 0.001）. ③ At 42 days after model establishment，Wnt4 expression was significantly up-regulated and Wnt7a expression was down-regulated（P < 0.05）.④ Wnt4 mRNA decreased at dpi 1 ，3 ，7（P < 0.01）. Wnt7a mRNA decreased at dpi 1 ，3 ，7 ，14 ，21（P < 0.05）.【Conclusions】① Neuropathic pain is induced after SCI. Mechanical allodynia but not thermal hyperalgesia shows different sensitivity to different degrees of spinal cord injury. ② Expression changes of Wnt4 and Wnt7a suggest they may play an important role in the plasticity of motor neural circuits after spinal cord injury.