Development of a Rabbit Model of Radiation-Induced Sciatic Nerve Injury: In Vivo Evaluation Using T2 Relaxation Time Measurements
Development of a Rabbit Model of Radiation-Induced Sciatic Nerve Injury: In Vivo Evaluation Using T2 Relaxation Time Measurements
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DOI：
10.1097/rct.0000000000000241
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发表时间：
2015-07
影响因子：
1.3
通讯作者：
Q. Wan;Qian Zeng;Xinchun Li;Chongpeng Sun;Jia-xuan Zhou;Qiao Zou;Ying-shi Deng;Daoli Niu
中科院分区：
文献类型：
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作者：
Q. Wan;Qian Zeng;Xinchun Li;Chongpeng Sun;Jia-xuan Zhou;Qiao Zou;Ying-shi Deng;Daoli Niu
目的建立放射性坐骨神经损伤（RISNI）的动物模型，评价CT引导立体定向放射外科技术对损伤神经T2测量的价值。材料与方法20只新西兰大白兔随机分为A组（n = 5）和B组（n = 15）。A组行CT和磁共振扫描，然后处死，比较坐骨神经的影像学和解剖学。B组兔一侧坐骨神经分别接受35、50和70戈伊的照射（每组n = 5）。在照射前和照射后1、2、3和4个月进行磁共振成像和功能评估。结果CT和MRI均能观察到坐骨神经在骨盆外的股段。35-戈伊组照射神经T2值逐渐增加，4个月时达到峰值; 50-戈伊组T2值增加较快，3个月时达到峰值。35-戈伊组和对照组之间在3个月和4个月时存在显著差异，50-戈伊组和对照组之间在2个月、3个月和4个月时存在显著差异。50-戈伊组的功能评分逐渐下降，而35-戈伊组的评分在治疗后3个月达到低点，然后恢复。受照肢体的功能评分与T2值呈负相关（r =-0.591和-0.595，P < 0.05）。电子显微镜显示35-和50-戈伊组的照射神经的进行性变形和变性，这在50-戈伊组更严重。结论兔股中段坐骨神经单次照射35和50戈伊可建立RISNI模型。虽然T2值对于监测RISNI是有用的，但它们可能不够敏感，无法评估其严重程度。
Objectives To develop a rabbit model of radiation-induced sciatic nerve injury (RISNI), using computed tomography (CT)–guided stereotactic radiosurgery, and assess the value of T2 measurements of injured nerves. Materials and Methods Twenty New Zealand rabbits were randomly divided into A (n = 5) and B (n = 15) groups. Group A rabbits underwent CT and magnetic resonance scan and were then killed for comparison of images and anatomy of sciatic nerves. One side of the sciatic nerve of group B rabbits received irradiation doses of 35, 50, or 70 Gy (n = 5 per group). Magnetic resonance imaging and functional assessments were performed before irradiation and 1, 2, 3, and 4 months thereafter. Result The thigh section of the sciatic nerve outside the pelvis could be observed by CT and magnetic resonance imaging. T2 values of the irradiated nerve of the 35-Gy group increased gradually, peaking at 4 months; T2 values of the 50-Gy group increased faster, peaking at 3 months. Significant differences between the 35-Gy and control groups were found at 3 and 4 months, and between the 50-Gy and control groups at 2, 3, and 4 months. Functional scores of the 50-Gy group declined progressively, whereas the 35-Gy group scores reached a low point at 3 months posttreatment and then recovered. Functional scores of the irradiated limbs demonstrated a negative correlation with T2 values (r = −0.591 and −0.595, P < 0.05). Electron microscopy revealed progressive deformation and degeneration of the irradiated nerve in the 35- and 50-Gy groups, which were more severe in the 50-Gy group. Conclusions A rabbit RISNI model can be produced using the midthigh segment of the sciatic nerve and single-fraction doses of 35 and 50 Gy. Although T2 values are useful for monitoring RISNI, they may not be sensitive enough to evaluate its severity.