Kilani R T, Mackova M, Davidge S T, Guilbert L J
University of Alberta Perinatal Research Centre, University of Alberta, Edmonton, Canada.
Placenta. 2003 Sep-Oct;24(8-9):826-34. doi: 10.1016/s0143-4004(03)00129-2.
In pregnancies complicated by intrauterine growth restriction (IUGR), the villous trophoblast shows increased apoptosis and immature cytotrophoblasts (CT) may be exposed to both higher or lower oxygen levels than normal placentae. We propose that villous CT undergo higher frequencies of apoptosis at extreme oxygen tensions. The apoptosis of CT isolated from normal term placentae was examined before culture and after 24 h of culture at different oxygen tensions with or without TNFalpha. The apoptosis frequencies of cells cultured for 24 h at O2 levels of approximately 15 mm and approximately 38 mm Hg were similar to the frequency before culture. Both constitutive and TNFalpha-induced apoptosis and cell loss were highest at low (<10 mm Hg) and high ( approximately 140 mm Hg) oxygen tensions. Further, the ratios of induced to constitutive apoptosis, constant from approximately 15 mm to approximately 140 mm Hg, indicate induced apoptosis to be rather insensitive to changes in oxygen levels. These results show that primary villous trophoblasts from normal placentae undergo minimal apoptosis unless subjected to extreme oxygen tensions <15 mm or 140 mm Hg. The results indicate that normal villous trophoblasts are remarkably resistant to hypoxia-induced apoptosis.
在合并有宫内生长受限（IUGR）的妊娠中，绒毛滋养层细胞凋亡增加，与正常胎盘相比，未成熟的细胞滋养层细胞（CT）可能暴露于更高或更低的氧水平。我们提出，在极端氧张力下，绒毛CT经历更高频率的凋亡。在不同氧张力下，有或无肿瘤坏死因子α（TNFα）的情况下，对从正常足月胎盘分离的CT在培养前和培养24小时后的凋亡情况进行了检测。在约15 mmHg和约38 mmHg的氧水平下培养24小时的细胞凋亡频率与培养前的频率相似。在低（<10 mmHg）和高（约140 mmHg）氧张力下，组成性和TNFα诱导的凋亡及细胞丢失均最高。此外，从约15 mmHg至约140 mmHg诱导凋亡与组成性凋亡的比率恒定，表明诱导凋亡对氧水平变化相当不敏感。这些结果表明，除非处于<15 mmHg或140 mmHg的极端氧张力下，正常胎盘的初级绒毛滋养层细胞经历的凋亡极少。结果表明，正常绒毛滋养层细胞对缺氧诱导的凋亡具有显著抗性。
