表皮神经嵴干细胞移植对大鼠脊髓损伤后GDNF表达的影响及意义

Glial cell line-derived neurotrophic factor expression after epidermal neural crest stem cells transplantation in spinal cord injury of rats

目的探讨表皮神经嵴干细胞（EPI-NCSC）移植对大鼠损伤脊髓修复过程中胶质细胞源性神经营养因子（GDNF）表达的影响。方法分离培养绿色荧光蛋白转基因大鼠的EPI-NCSC，备移植用。取30只SD大鼠，暴露T，o脊髓并在NYU_Ⅱ撞击机下以10g×25rnlTl的致伤力挫伤脊髓建立脊髓损伤模型，大鼠分为空白损伤组、DMEM对照组和实验组。脊髓损伤后1周，将EPI-NCSC悬液注射入大鼠损伤的脊髓处，DMEM对照组用单纯的DMEM／F12培养液代替，空白损伤组未处理。脊髓损伤后每周进行1次BBB评分以评估大鼠的运动功能，移植后6周取材，检测GDNFmRNA及GDNF蛋白的表达。结果实验组大鼠的BBB评分从移植后第2周开始就显著高于其他两组，差异均有统计学意义（P〈0．05）。实验组损伤的脊髓组织处GDNFmRNA和蛋白的表达均明显高于其他两组，差异均有统计学意义（P〈0．05）。而空白损伤组和DMEM对照组间BBB评分及GDNFmRNA和蛋白表达量均无明显差异（P〉0．05）。结论EPI-NCSC移植后，EPI-NCSC能促进大鼠脊髓组织GDNF的表达，从而有助于修复大鼠损伤的脊髓。

Objective To explore the expression of glial cell line-derived neurotrophic factor （GDNF） in rats with spinal cord injury （SCI） after epidermal neural crest stem cells （EPI-NCSCs） transplantation. Method EPI-NCSCs were isolated from GFP transgenic rats for transplantation. The rat SCI model was made by NYU-II impactor （ 10 g 25 mm） at T10 level. Then 30 SD rats were randomly divided into blank injury group （group A）, DMEM transplantation group （group B）, and experimental group （group C）. The EPI-NCSCs were transplanted into the injured region one week after SCI. In DMEM group, the DMEM/F12 was used to substitute for the EPI-NCSCs. No treatment was done in blank injury group. The locomotor function was appraised by BBB score every week after transplantation. At sixth week after transplantation, GDNF mRNA and protein expression was detected. Result The BBB score in experimental group was significantly higher than the other two groups from two weeks after transplantation （P〈O. 05）. The expression of GDNF mRNA and protein in experimental group was significantly higher than the other two groups （P〈0. 05）. There was no significant difference between blank injury group and DMEM transplantation group （P〉 0. 05）. Conclusion The expression of GDNF can be up-regulated by EPI-NCSCs transplantation, which may be one of the mechanisms for EPI-NCSCs reDairing SCI.