雌激素对脊髓继发性损伤保护作用的研究

Protective effect of estrogen on secondary spinal cord injury in rats

目的观察雌激素对脊髓继发性损伤的保护作用。方法采用Allen造模法建立脊髓损伤(SCI)模型。将成年雄性SD大鼠126只随机分为假手术组、SCI组和雌激素组,每组42只。采用免疫组织化学法和图像定量分析法观察SCI后凋亡调控因子Bax蛋白的表达,比色法检测各组丙二醛(MDA)的含量和超氧化物岐化酶(SOD)活性的变化,术后4周内经Basso-Beattie-Bresnahan(BBB)评分观察脊髓功能恢复情况。结果假手术组有少量散在的Bax蛋白表达,SCI组Bax蛋白表达的阳性细胞较假手术组明显增多(P<0.01),雌激素组较SCI组阳性细胞数明显减少(P<0.05);与SCI组比较,雌激素组MDA含量明显降低而SOD活性明显增高(P<0.05);手术后1周雌激素组较SCI组BBB评分明显增高(P<0.05)。结论雌激素可通过下调促细胞凋亡因子Bax蛋白表达和减少活性氧产生,从而可能在脊髓继发性损伤中发挥保护作用。

Objective To investigate the protective effect of estrogen on secondary injured spinal cord in rats. Methods The heavy-hammer-downcast-punch method （ Allen＇s method） were taken to establish the spinal cord injury （ SCI） models. Totally 126 adult SD male rats were randomly divided into the sham group,SCI group and estrogen group,42 rats in each group. The Bax protein expression after SCI was evaluated with immunohistochemical and image quantitative analysis. The malondialdehyde （ MDA） content and the superoxide dismutase（ SOD） activity of the injured spinal cord were measured with colorimetric technique after SCI. Functional status of spinal cord was assessed by the Basso-Beattie-Bresnahan（ BBB） score in the 4 weeks after operation. Results Little expression of Bax protein was found in sham group. Compared with the sham group,the expression of Bax protein in SCI group was increased markedly（ P 〈0. 01） . Compared with the SCI group,less expression of Bax protein was noted in the estrogen group（ P 〈0. 05） . Compared with the SCI group,the MDA content was markedly reduced and the SOD activity increased in the estrogen group（ P 〈0. 05） ; BBB score in the estrogen group was significantly higher than that in SCI group at 1 week after operation（ P 〈0. 05） . Conclusion Estrogen can downregulate the expression of Bax proctein and reduce the generation of reactive oxygen species,and it may play a protective role on secondary injured spinal cord.