Differential Expression of Wnt4 and Wnt7a in Mice with Different Degrees of Spinal Cord Injury / 中山大学学报(医学科学版)

ABSTRACT

spinal cord injury；non-canonical Wnt signaling pathway related genes；PCP related genes@#： 【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 differ⁃ ent 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.