用MR扩散张量成像评价犬急性脊髓损伤后神经前体细胞移植的作用

MR diffusion tensor imaging in the evaluation of neural progenitor cells transplantation to acute injured canine spinal cord

目的用MR扩散张量成像(diffusiontensorimaging,DTI)观察神经前体细胞移植对犬急性脊髓损伤的影响。方法经端粒酶转染人胚胎脑室下区(subventricularzone,SVZ)细胞建立永生化的神经前体细胞系,并转基因表达绿色荧光蛋白(greenfluorescentprotein,GFP)用于标记和示踪。制作犬T13脊髓左半横断损伤模型。8只犬于损伤后1周行细胞移植,移植点取脊髓半切损伤头侧和尾侧邻近区域的灰白质交界处,不用免疫抑制剂。分别于损伤前、损伤后1周、移植后1周(即损伤后2周)、移植后4周用DTI测量损伤侧和未损伤侧的表观扩散系数(apparentdiffusioncoefficient,ADC)值及部分各向异性(fractionalanisotropy,FA)值,并对结果进行统计学分析。结果损伤前、损伤后1周、移植后1周、移植后4周损伤侧的ADC值分别为(1.00±0.15)、(1.65±0.45)、(1.44±0.48)、(1.43±0.26)×10-3mm2/s,不同时间的差异有统计学意义(F=6.038,P=0.005);损伤侧的FA值分别为0.59±0.11、0.30±0.17、0.36±0.25、0.34±0.11,不同时间的差异有统计学意义(F=5.221,P=0.009)。未损伤侧的ADC值分别为(1.01±0.17)、(1.32±0.06)、(1.10±0.24)、(1.14±0.22)×10-3mm2/s,不同时间的差异无统计学意义(F=1.303,P=0.306);未损伤侧的FA值分别为0.60±0.09、0.38±0.25、0.46±0.15、0.50±0.21,不同时间的差异无统计学意义(F=2.797,P=0.072)。结论DTI对实验性脊髓损伤后脊髓损伤和修复过程的观察能提供有价值的信息。

Objective To observe the effect of transplantation of telomerase immortalized human neural progenitor cells to acute injured canine spinal cord by using MR diffusion tensor imaging （ DTI ）. Methods Telomerase immortalized human neural progenitor cells with expression of green fluorescent protein were prepared for transplantation. Eight adult canines with left spinal cord hemisection at the level of T13 were examined by MR diffusion tensor imaging four times sequentially： prior to injury, one week after injury, one week after transplantation （two weeks after injury ）, and four weeks after transplantation. Results The ADC values of the injured spinal cord were （ 1.00 ＋ 0. 15 ） ×10^-3mm^2/s, （ 1.65 ＋ 0. 45） ×10^-3mm^2/s, （1.44＋0.48） ×10^-3mm^2/s, and （1.43 ＋0.26） ×10^-3mm^2/s, respectively. There was statistically significant difference between the data obtained at different times （ F = 6. 038, P = 0. 005 ）. The FA values of the injured spinal cord were 0.59 ＋0. 11, 0.30 ＋0. 17, 0.36 ＋0.25, and 0.34 ＋0. 11, respectively. There was also statistically significant difference between the data obtained at different times （ F = 5. 221,P = 0. 009）. The ADC values of the intact spinal cord were （ 1.01 ＋ 0. 17 ） ×10^-3mm^2/s, （1.32 ＋0.06） ×10^-3mm^2/s, （1.10 ＋0.24） ×10^-3mm^2/s, and （1.14 ＋0.22） ×10^-3mm^2/s, respectively. There was no statistically significant difference between the data obtained at different times （ F = 1. 303, P = 0. 306 ）. The FA values of the intact spinal cord were 0. 60 ＋ 0. 09, 0. 38 ＋ 0. 25, 0. 46 ＋ 0. 15, and 0. 50 ＋0. 21, respectively. There was also no statistically significant difference between the data obtained at different times （ F = 2. 797, P = 0. 072）. Conclusion DTI can provide useful information for spinal cord injury and regeneration in experimental spinal cord injury.