大鼠脊髓损伤后Wnt信号分子的表达变化

目的:探讨大鼠脊髓损伤后不同时期Wnt信号分子Wnt-1、β-连锁蛋白(β-catenin)及糖原合成酶激酶-3β(GSK-3β)在脊髓损伤局部的表达情况.方法:50只成年雌性SD大鼠随机均分为对照组和实验组,麻醉下手术显露T9～T11椎板,切除T10全椎板,实验组大鼠用NYU打击器以10g×5cm的打击能量致伤T10脊髓,对照组只行全椎板切除,不致伤脊髓.分别于术后1d、3d、5d、7d、14d每组各取5只大鼠,取以损伤区为中心共15mm范围内(对照组取相应部位)脊髓组织,提取总RNA,采用半定量RT-PCR的方法检测脊髓组织中Wnt-1、β-catenin及GSK-3β的mRNA表达量.结果:脊髓损伤后1d和3d时Wnt-1和β-catenin出现高表达,5d后其表达逐渐减弱,14d左右其表达基本恢复到正常水平,而在脊髓损伤后1d和3d时GSK-3β呈低表达,5d后其表达逐渐增强,各时间点之间差异有显著性(P<0.05).对照组中Wnt-1和β-catenin及GSK-3β均呈低表达,各时间点表达无显著差异(P<0.05).结论:大鼠脊髓损伤后损伤局部脊髓组织中Wnt-1,β-catenin及GSK-3β的表达发生变化,提示Wnt信号在脊髓损伤后的早期被激活,其可能与脊髓损伤后的修复再生有关.

The expression of Wnt signaling gene after spinal cord injury in rats

Objective:To observe the changes of expression of Wnt signaling gene Wnt-l,p-catenin and glycogen synthase kinase-3β (GSK-3β) at different time period following spinal cord injury in rats.Method: Fifty adult female SD rats were randomly divided into two groups:the sham group (only laminectomy,n=25) and the spinal cord injury (SCI) group (n=25).SCI model was established by hitting T10 spinal cord with NYU impactor in the force of 10g×5cm.The total RNA of the spinal cord tissue was extracted for the examination of the mRNA expression of Wnt-1 ,β-catenin and GSK-3β by using RT-PCR at the 1,3,5,7 and 14 days after spine injury or laminectomy.Result:In the SCI group,the expression of Wnt-1 and β-catenin mRNA had a notable increase at 1 and 3 days after injury,then the expression began to decrease at 5 days after injury and it was almost back to normal after 14 days.GSK-3P mRNA showed low expression at 1 and 3 days after injury and the expression began to increase at 5 days later.The lower expression of Wnt-1, β-catenin and GSK-3β was observed in the sham group and presented no significant difference in the expressions among the different time periods (P>0.05).Conclusion:The expression changes of Wnt-1 ,β-catenin and GSK-3β mRNA after spinal cord injury suggest that Wnt signaling may play an important role in the neural regeneration after spinal cord injury.