肿瘤坏死因子在减压病兔脊髓组织损伤中的作用

Role of tumor necrosis factor-alpha in spinal cord injury of rabbits with decompression sickness

目的观察减压病（DCS）导致兔脊髓组织损伤的病理学改变，探讨肿瘤坏死因子-α（TNF-α）在减压病脊髓损伤中的作用。方法家兔随机分为正常对照组、DCS组、安全减压组。制备DCS模型，借助光学显微镜、荧光实时定量法和免疫组化方法观察胸腰段脊髓病理形态学改变、TNF-α mRNA和蛋白表达变化；用脱氧核苷酸末端转移酶介导的脱氧尿三磷酸缺口末端标记（TUNEL）法观察脊髓组织细胞凋亡情况。结果DCS组脊髓白质内空泡形成，损伤区周围胶质细胞增生，TNF-α mRNA和蛋白表达量较正常对照组和安全减压组均明显增加，差异有统计学意义（P〈0．01）；TUNEL标记阳性凋亡细胞数较正常对照组及安全减压组均明显增多，差异均有统计学意义（P〈0．05）。结论细胞凋亡是DCS致脊髓损伤的重要方式，在DCS早期TNF-α即可大量释放并可启动凋亡程序，参与DCS脊髓损伤的病变进程。

Objective To observe the pathological changes in rabbits with spinal cord injury induced by decompression sickness （DCS）, and to investigate the role of tumor necrosis factor-alpha （TNF-α） in spinal cord injury induced by DCS. Methods Rabbits were randomly divided into normal control group, DCS group, and safe decompression group. The rabbit model of DCS was established. Light microscopy, real-time PCR, and immunohistochemical method were used to observe the pathomorphological changes in the thoracolumbar spinal cord and the mRNA and protein expression of TNF-α, respectively. The terminal deoxynucleotidyl transferase- mediated dUTP nick end labeling （TUNEL） was used to observe the apoptosis in the spinal cord. Results In the DCS group, cavities formed in the white matter of spinal cord and gliosis occurred around necrotic areas. Moreover, the mRNA and protein expression of TNF-α was significantly higher in the DCS group than in the normal control group and the safe decompression group （P〈0.01）. The results of TUNEL showed that the number of positive apoptotic cells was significantly larger in the DCS group than in the normal control group and the safe decompression group （P 〈0.05）. Conclusion Apoptosis plays an important role in spinal cord injury induced by DCS. In the early stage of DCS, the massive release of TNF-α initiates apoptosis and contributes to the pathological changes in spinal cord injury induced by DCS.