雌激素影响急性大鼠脊髓损伤后细胞凋亡的相关性实验研究

目的在建立大鼠脊髓损伤模型基础上，观察不同时间点雌激素对脊髓胶质细胞，神经元凋亡的影响，以期为临床急性脊髓损伤的治疗提供理论依据。方法健康成年大鼠72只，随机分为两组，其中单纯损伤组（单纯打击损伤）36只，雌激素组（手术加雌激素）36只。脊髓损伤动物模型的制备：用自制Allen打击器25gcm致伤力撞击脊髓，制成脊髓损伤动物模型。雌激素组每日肌注雌激素（100μg／kg）直至处死，单纯损伤组仍每日肌注生理盐水0．5ml直至处死。组织切片的制备：脊髓损伤后1d、3d、5d、8d、14d、21d共6个时间段分批处死动物。4％多聚甲醛心肌灌注固定24h，切取每只大鼠T5～T13节段脊髓组织，常规制成切片，给于Bcl－2检测，TUNEL原位末端标记，检测大鼠脊髓损伤后细胞凋亡的情况。脊髓损伤后2周给予Gale评分及斜板维持试验。结果Bcl－2蛋白检测：在脊髓损伤后的第1天，脊髓组织即开始较高表达Bel－2蛋白。单纯损伤组Bcl－2高峰发生在损伤后3天，而雌激素组伤后8天达到高峰，此时Bcl－2蛋白不仅表达在神经细胞中，更多的在胶质细胞中大量表达，且此状态一直维持到伤后14天才开始下降，伤后21天仅少量表达（P〈0．05）。TUNEL原位标记检测：单纯损伤组24小时已出现不少阳性细胞，以胶质细胞为主．3～8天达到高峰，此后逐渐回落，但21天时仍有阳性细胞，应用雌激素治疗后，凋亡细胞明显减少（P〈0．05）。脊髓损伤后2周Gale评分及斜板维持率雌激素组优于单纯损伤组（P〈0．01）。结论雌激素在脊髓损伤中通过改善微循环，促进Bcl－2蛋白的表达，清除氧自由基，抗氧化作用能够抑制脊髓损伤早期神经细胞和胶质细胞的凋亡，从而减轻脊髓继发性损伤．促进脊髓神经功能的恢复。所以脊髓损伤后早期应用雌激素配合其它药物阻止神经细胞和胶质细胞的凋亡可能有助于减轻脊髓损伤的损害程度，促进脊髓神经功能的恢复，为SCI的治疗提供一个新的途径。

The effect of estrogen on apoptosis following acute spinal cord injury in rats

Objective In rats model of spinal cord injury,to explore the estrogen on apoptosis following spinal cord injury in different time. Methods 72 healthy rats were chosen and their body weight varied from 250 gram to 310 gram.The rats were divided into two groups randomly：controlled group（36 cases） and estrogen group（36 cases）. All of rats spinal cord injury model were established with Allen bump equipment（25gcm）.The model of estrogen group injected estrogen （100μg/kg） every day until they were sacrificed. The model of controlled group injected NS（0.5ml/d） every day until they were sacrificed. Fabrication of tissue section：after spinal cord injury ld,3d,5d,Sd,14d,21d,sacrificed rats in batch.4% formaldehydum polymerisatum were pured into the cardiac muscle and fixed for 24h.Then obtain the specimen of spinal cord from T5 to T13.Establishing slices,HE dyeing, bcl-2 dectation,terminal doxynucleotidyl transferase-mediated dUTP nick end labeling （TUNEL）. Results Bcl-2 dectation： During the first day after spinal cord injury,many bcl-2 protein in the spinal cord tissue were found.In control group,they reached the peak on the third day after spinal cord injury.In estrogen group,they reached the peak on the eighth day after spinal cord injury.Bcl-2 protein were more in glial cells than those in nerve cells.They began to decrease after the fourteenth day of spinal cord injury （P〈0.05）. Tunel dectation：In control group,after 24 hours, were many positive cells,most of them were glial cells,it reached the peak after 3-8 day,and then,they were decreased gradually.In estrogen group,positive cells were obviously less than those of control group （P〈0.05）. Conclusion Estrogen can improve the microcirculation,get rid of oxygen free radical,resist oxygenation,so as to restrain the apoptosis of nerve cell and glial cell,lesson spinal cord injury,improve to recover spinal nerve. Therefore,during early time of spinal cord injury,using estrogen with other medicine,it can lesson spinal cord injury and provide a new method for treatment of spinal cord injury.