金属螺钉与聚氨酯橡胶慢性脊髓损伤大鼠模型的分析比较

目的:比较金属螺钉与聚氨酯橡胶压迫的慢性脊髓损伤（CSCI）大鼠模型的优劣,探索适合CSCI研究的大鼠模型。方法: 108只雄性Sprague-Dawley大鼠完全随机分组为假手术组（n=36）、金 属螺钉组（n=36）和聚氨酯橡胶组（n=36）,记录造模术前及术后2.5 h、7 d、14 d、21 d、28 d各组下肢行为学运动功能评分（BBB评分）和体感诱发电位（SEP）,取C5段脊髓组织行苏木精-伊红染色 法（HE）和原位末端标记法（TUNEL）染色。结果:BBB评分:金属螺钉组与聚氨酯橡胶组较假手术组均明显降低（金属螺钉组比假手术组,t=9.671,P<0.000 1;聚氨酯橡胶组比假手术组,t=4.997, P=0.002 5）,且金属螺钉组评分低于聚氨酯橡胶组（t=2.705,P=0.035 3）,金属螺钉组持续下降,聚氨酯橡胶组则于术后21 d降至最低后开始上升。SEP:金属螺钉组与聚氨酯橡胶组较假手术组均出 现潜伏期延长（金属螺钉组比假手术组,t=18.02,P<0.000 1;聚氨酯橡胶组比假手术组,t=10.82,P<0.000 1）和波幅下降（金属螺钉组比假手术组,t=145.5,P<0.0001;聚氨酯橡胶组比假手术组, t=3.97,P= 0.007 4）,且金属螺钉组潜伏期延长时间长于聚氨酯橡胶组,金属螺钉组波幅降低幅度先大于聚氨酯橡胶组,后较之略低。HE染色:金属螺钉组与聚氨酯橡胶组均出现脊髓损伤的病理表现 ,且金属螺钉组从腹侧到背侧渐进性加重,聚氨酯橡胶组则表现为一致性。TUNEL染色:金属螺钉组与聚氨酯橡胶组较假手术组TUNEL阳性细胞数明显增多（金属螺钉组比假手术组,t=4.722,P=0.003 2 ;聚氨酯橡胶组比假手术组,t=8.263,P=0.000 2）,且主要集中于脊髓灰质前角。金属螺钉组在术后第7天阳性细胞数达到最高,之后明显减少,聚氨酯橡胶组在术后逐渐增加至术后21 d达到最高。结 论:两种模型均有效地模拟了CSCI,金属螺钉CSCI模型适合损伤程度逐渐加重的CSCI研究,聚氨酯橡胶CSCI模型则适合压迫程度稳定的CSCI研究。

Analysis and comparison of chronic spinal cord injury in rat model with metal screw and polyurethane rubber

Objective: To explore the rat model suitable for chronic spinal cord injury(CSCI), and to compare the advantages and disadvantages of CSCI rat model with metal screw and polyurethane rubber compression. Methods: A total of 108 male Sprague-Dawley rats were randomly divided into sham operation group, metal screw group and polyurethane rubber group. The lower limb motor function scores(BBB scores) and the somatosensory evoked potency (SEP) were recorded at before and 2.5 hours,7 days, 14 days, 21 days and 28 days after the operation. The HE staining and the TUNEL were used for C5 spinal cord. Results: BBB scores showed that compared with sham operation group, metal screw group and polyurethane rubber group were significantly lower(metal screw group vs. sham operation group t=9.671,P<0.000 1; polyurethane rubber group vs. sham operation group t=4.997, P=0.002 5), and the metal screw group score was lower than the polyurethane rubber group(t=2.705,P=0.035 3). BBB score in the metal screw group continued to decrease, while the polyurethane rubber group score firstly decreased to the lowest 21 days after operation and then it began to rise. SEP indicated that compared with sham operation group, metal screw group and polyurethane rubber group showed prolonged latency(metal screw group vs. sham operation group t=18.02,P<0.000 1; polyurethane rubber group vs. sham operation group t=10.82,P<0.000 1) and decreased amplitude(metal screw group vs. sham operation group t=145.5,P<0.000 1; polyurethane rubber group vs. sham operation group t=3.97, P=0.007 4), and the latency period of the metal screw group was longer than that of polyurethane rubber group. The degree of amplitude reduction of the metal screw group was greater than that of polyurethane rubber group. HE staining showed that the pathological appearance of spinal cord injury was observed in metal screw group and polyurethane rubber group, and the metal screw group gradually increased from the ventral to the dorsal side, while the polyurethane rubber group showed consistency. TUNEL staining indicated that the number of TUNEL positive cells in metal screw group and polyurethane rubber group was significantly greater than that in the sham operated group(metal screw group vs. sham operation group t=4.722,P=0.003 2; polyurethane rubber group vs. sham operation group t=8.263,P=0.000 2), and was mainly concentrated in the anterior horn of gray matter. The number of TUNEL positive cells in the metal screw group reached the highest at 7 days after operation, and then decreased significantly, while the polyurethane rubber group reached the highest at 21 days after operation. Conclusion: Both models are effective in simulating CSCI. Furthermore, the CSCI model of metal screw is suitable for the CSCI research with gradually increasing degree of compression, while the CSCI model of polyurethane rubber is suitable for CSCI research with stable degree of compression.