大鼠脊髓损伤后内源性神经干细胞增殖过程中Wnt-1的表达

Expression of Wnt-1 in the proliferation process of endogenous neural stem cells after spinal cord in-jury in rats

目的:探讨大鼠脊髓损伤后信号蛋白Wnt-1的表达及其与脊髓内源性神经干细胞(ENSCs)早期增殖的关系。方法:30只Wister成年大鼠,随机分为正常对照组(A组,n=5)和损伤组(B组,n=25)。A组不损伤脊髓,B组在大鼠T10采用经典Allen′s打击法(25g·cm)造成脊髓损伤,于造模后1d、3d、1周、2周、4周进行取材,对距离损伤中心5mm的脊髓行免疫组化染色,检测ENSCs的增殖及Wnt-1蛋白表达的动态变化,与A组比较,并统计分析二者之间的相关性。结果:30只大鼠均进入结果分析。A组脊髓在中央管周围、外周软膜可见极少数BrdU/Nestin阳性细胞,白质中几乎没有。B组中BrdU/Nestin阳性细胞于损伤后24h表达于室管膜以及软膜,灰质和白质亦有少量表达,3d时明显增多,1周达到高峰(P<0.05),2周开始逐渐下降,4周时仍可见少量BrdU/Nestin阳性细胞。B组各时间点与A组比较差异有显著性意义(P<0.05)。B组大鼠各时间点均有Wnt-1蛋白的表达,损伤后第1天开始表达,3d达到高峰,一直至脊髓损伤后2周Wnt-1都维持在较高的表达水平。Wnt-1蛋白的表达与Nestin的表达具有相关性(r=0.893,P<0.05)。结论:大鼠脊髓损伤后信号蛋白Wnt-1表达增加,其可能与大鼠ENSCs的早期增殖有关。

Objective：To investigate the expression of Wnt-1 in the earlier proliferation process of endogenous neural stem cell （ENSC） after spinal cord injury in rats.Method：30 Wister rats were randomly divided into two groups,the normal control group（group A,n=5） and the spinal cord injury group（group B,n=25）, the spinal cord injury were made at T10 level by Allen＇s method in group B.The rats were killed at ld,3d, 1,2 and 4 weeks after the injury,the expression of Wnt-1 and the proliferation of ENSCs were analyzed in the samples by immunohistochemistry,which were harvested 5mm to the injury center of the spinal cord both cephalad and caudally.The statistical analysis was used to evaluate the correlation between the expression of Wnt-1 and the proliferation of ENSCs.Result：All 30 rats were involved in the result analysis.It was showed that BrdU/Nestin positive cells presented in every spinal cord injury group.The BrdU/Nestin positive ceils began to increase on the first day after SCI and increased noticeablely.On the 3rd day,it reached the peak on the 7th day,and gradually reduced on the 14th and 28th days.There were significantly differences in BrdU/Nestin positive cell between normal control group and SCI group （P〈0.05）.Wnt-1 positive cells expressed in every SCI group.It was showed a little expression of Wnt-1 positive cell on the first day after SCI.The level of Wnt-1 protein in NSCs increased significantly,peaked at 3 days and remained at high levels until 14 days after SCI.The level of nestin protein was closely correlated with the level of Wnt-1 protein （r=0.893,P〈 0.05）.Conclusion：SCI can promote the proliferation of ENSCs in rats,which is correlated with the activation of Wnt signaling pathway.