HIF-1α基因修饰神经干细胞移植对大鼠损伤脊髓NF200和GFAP表达的影响

Effect of Transplantation of HIF-1αGene-modified Neural Stem Cells on Expressions of Neurofilament 200 and GFAP in Injured Spinal Cord Tissues in Rats

目的研究低氧诱导因子-1α(HIF-1α)基因修饰的神经干细胞移植对大鼠脊髓损伤后神经丝蛋白200(NF200)和胶质纤维酸性蛋白(GFAP)表达的影响及意义。方法采用电控脊髓损伤打击装置制作大鼠脊髓损伤模型。按随机数字表将120只SD大鼠平均分为4组:假手术组(Sham组),单纯损伤组(SCI组),神经干细胞组(NSC组)和HIF-1α基因修饰NSC组(HIF-NSC组)。应用免疫组化法检测受伤脊髓中HIF-1α、NF200和GFAP的表达。结果HIF-NSC组中HIF-1α免疫阳性细胞平均光密度值比其他各组各时间点均高(P<0.01),且表达高峰延迟至移植后14 d;除第1天外,HIF-NSC组NF200表达比SCI组和NSC组明显增高(P<0.05),移植后28 dNF200免疫阳性轴突数目也比SCI组和NSC组明显增多(P<0.01);移植后7 d、14 d、28 dGFAP免疫阳性细胞面积均比SCI组和NSC组明显减少(P<0.01)。结论HIF-1α基因修饰NSC移植可引起HIF-1α在损伤脊髓内有效表达,且能明显的促进NF200的表达,并能在脊髓损伤的后期抑制GFAP的表达。这提示HIF-1α基因修饰的NSC移植可减少受伤脊髓中胶质细胞的增生和胶质疤痕的形成,促进轴突再生。

Objective To study of the effect of transplantation of hypoxia inducible factor-1α （HIF-1α） gene-modified neural stem cells （NSCs） on the expressions of neurofilament 200 （NF200） and glial fibrillary acidic protein （GFAP） in the injured spinal cord in rats. Methods One hundred twenty SD rats were randomly divided into four groups, i.e. sham group, spinal cord injury （SCI） group, NSC group, and HIF-NSC group, of 30 rats each. SCI was induced by electricity-controlled spinal cord injuring device. The expressions of HIF-1α, NF200 and GFAP in the injured spinal cord tissues were detected by immunohistochemical staining. Results The optical density （OD） value of HIF-lct imminnostaing-positive cells was significantly higher in HIF-NSC group than that in sham, SCI and NSC groups 1, 3, 7, 14 and 28 days after transplantation （P〈O.O1）, and its expression peak was postponed to 14 d after the transplantation. The OD value of NF200 imminnostaing-positive axons was significantly higher in HIF-NSC group than that in SC1 group and NSC group 3, 7, 14 and 28 days after the transplantation （P〈O.05）. The number of NF200 immunostaining positive axons in HIF-NSC group was significantly more than that in SCI group and NSC group 28 days after the transplantation （P〈O.01）. GFAP immunostaining positive cells area was significantly smaller in HIF-NSC group than that in SCI group and NSC group 7, 14 and 24 days after the transplantation （P〈0.O1）. Conclusions The transplantation of HIF-1 ot gene-modified NSCs can significantly produce expression of HIF-1α, upregulate the expression of NF200, and inhibit the expression of GFAP in the injured spinal cord in the rats. It is suggested that the transplantation of HIF-lct gene-medified NSCs may decrease glial scar and promote regeneration of the injured neural axons.