胎儿中枢神经组织细胞凋亡与神经管缺陷关系的初探

Apoptosis in tissues of the central nervous system of fetuses with neural tube defects：a preliminary study

目的：探讨胎儿中枢神经组织细胞凋亡与神经管缺陷（NTDs）发生的关系。方法采用病例对照研究设计，收集产前诊断引产或死胎死产 NTDs 胎儿为 NTDs 组；非缺陷引产胎儿为对照组。通过病理解剖，获得 NTDs 组与对照组脊髓组织标本23和21例，NTDs 组和对照组脑组织标本30和20例。应用 Western blot 法检测脊髓和脑组织中细胞凋亡关键酶 Caspase 3、Caspase 8及 Caspase 9蛋白及其裂解产物表达水平。结果 NTDs 组和对照组脊髓组织或脑组织中均可检测到 Caspase 蛋白条带，NTDs 组中枢神经组织 Caspase 的裂解激活产物cleaved Caspase 蛋白条带较明显。NTDs 组脊髓组织和脑组织中 cleaved Caspase 3（17 kD）和 cleaved Caspase 8（18 kD）的表达 IOD 水平略高于对照组，但差异无统计学意义；两组 cleaved Caspase 9（37／35 kD）比较，差异无统计学意义。无脑胎儿脊髓组织和脑膨出胎儿脑组织中 cleaved Caspase 3（17 kD）表达水平高于对照组；无脑胎儿脊髓组织中 cleaved Caspase 8（18 kD）及脊柱裂胎儿脑组织中 cleaved Caspase 8（43／41 kD）表达水平高于对照组；差异均有统计学意义。结论人胚胎中枢神经组织细胞过度凋亡可能与 NTDs 发生有关，NTDs 发生过程中细胞过度凋亡可能通过 Caspase 8裂解激活诱导的外源性凋亡途径。

Objective To examine the role of apoptosis in the development of human neural tube defects （NTDs）. Methods A case-control study was conducted.Cases were fetuses terminated due to prenatal diagnosis of NTDs or stillborn neonates with NTDS,and controls were terminated fetuses without congenital malformations.Fetal spinal cord tissues from 23 NTD cases and 21 controls,and fetal brain tissues from 30 NTD cases and 20 controls were obtained by autopsy.To evaluate apoptosis and apoptotic pathway,the expression levels of caspase 3 /8 /9 proteins in fetal spinal cord and brain tissues were determined by Western blot. Results Stripes of caspase and cleaved caspase were observed in fetal spinal cord tissues and fetal brain tissues of both NTD cases and controls,but stripes of cleaved caspase were more obvious in NTD cases.The expression levels of cleaved caspase 3 （1 7 kD）and cleaved caspase 8 （1 8 kD）in fetal spinal cord and brain tissues of NTD cases were tended to be higher than those of the controls,and there was no significant difference in the expression of cleaved caspase 9 （37 /35 kD）between NTD cases and controls both in fetal spinal cord and brain tissues.However,the expression level of cleaved caspase 3 （1 7 kD）was significantly higher in fetal spinal cord tissues of anencephalic cases and fetal brain tissues of encephalocele cases than in controls （P 〈0.05）.The expression levels of cleaved caspase 8 （1 8 kD）in fetal spinal cord tissues of anencephalic cases and cleaved caspase 8 （43 /41 kD） in fetal brain tissues of spina bifida cases were also significantly higher than those in controls （P 〈0.05 ）. Conclusion Excessive apoptosis in fetal central nervous tissues was associated with the development of NTDs.Apoptosis may be activated through extrinsic apoptosis pathway mediated by caspase 8.