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The role of Bcl-2 and Bax in hypoxia-induced caspase-3 activation in the fetal superior colliculus: in vivo optical

Bcl-2 和 Bax 在缺氧诱导胎儿上丘 caspase-3 激活中的作用：体内光学

基本信息

批准号：
17591143
负责人：
SAKATA Yoshiyuki
金额：
$ 2.24万
依托单位：
Yamaguchi University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-17591143/
关键词：
hypoxia fetal brain Bcl-2 Bax siRNA caspase-3 apoptosis optical imaging カスパーゼー3活性 ROS

项目摘要

The fetal brain is known to be survival from severe hypoxia during delivery, although its physiological mechanism remains unclear. We studied the roles of Bcl-2 (caspase-3 suppressor) and Bax (caspase-3 accelerator) in the hypoxia-induced activation of caspase-3 (final triggering apoptosis factor) in the superior colliculus (SC) in a fetal rat (embryonic day 22), which was still connected with the anesthetized dam (urethane, 1.2-1.4 g/kg, i.p.) by the umbilical cord. Caspase-3 activity was measured with fluorescent caspase-3 substrate using an optical imaging system. Hypoxia was induced by the umbilical cord occlusion for 5 minutes. After the initial occlusion and reperfusion of umbilical blood flow, the 2nd-5th occlusions were repeated with reperfusion at 2-5 hours after the first occlusion. The Bcl-2-siRNA or Bax-siRNA was applied into cells of the SC by electropolation. Apoptosis of fetal SC was measured by using the anti-ssDNA antibody. Apoptosis appeared during the occlusion and at 1-5 hrs after the reperfusion of the umbilical cord. Caspase-3 activity was increased transiently during the occlusion and long-lasted largely after the reperfusion. A low dose of Bcl-2 inhibitor did not affect on caspase-3 activity during the occlusion and after the reperfusion. But, high dose of Bcl-2 inhibitor unexpectedly suppressed the caspase-3 activity. Bax inhibitor had no effect on caspase-3 activity. Further, changes in caspase-3 activity of the fetal rats were examined using Bcl-2siRNA and Bax-siRNA to inhibit Bcl-2 and Bax synthesis. Bcl-2-siRNA caused statistically insignificant increases in caspase-3 activity after the 2nd and 3rd reperfusions, whereas Bax-siRNA induced significant decreases. The results suggest that Bcl-2 and Bax may act on an apoptosis cascade in the immature brain during severe hypoxia.

胎儿大脑在分娩过程中可从严重缺氧中存活，但其生理机制尚不清楚。本实验研究了缺氧诱导的大鼠胚胎上级丘（SC）caspase-3（最终触发凋亡因子）激活中Bcl-2（caspase-3抑制因子）和Bax（caspase-3促进因子）的作用。被脐带缠住了使用光学成像系统用荧光胱天蛋白酶-3底物测量胱天蛋白酶-3活性。通过脐带闭塞5分钟诱导缺氧。在第一次阻断和脐血流再灌注后，重复第2 - 5次阻断，并在第一次阻断后2-5小时再灌注。通过电极化将Bcl-2-siRNA或Bcl-2-siRNA施加到SC的细胞中。用抗ssDNA抗体检测胎儿SC的凋亡。细胞凋亡出现在脐带阻断期间和再灌注后1-5小时。Caspase-3活性在缺血过程中短暂升高，在再灌注后持续很长时间。低剂量Bcl-2抑制剂对缺血再灌注后caspase-3活性无明显影响。但是，高剂量的Bcl-2抑制剂意外地抑制caspase-3活性。Bax抑制剂对caspase-3活性无影响。此外，使用Bcl-2siRNA和Bcl-siRNA抑制Bcl-2和Bax合成，检测胎鼠caspase-3活性的变化。Bcl-2-siRNA在第2次和第3次再灌注后引起caspase-3活性的统计学上不显著的增加，而Bcl-2-siRNA诱导了显著的降低。结果表明，Bcl-2和Bax可能在严重缺氧的未成熟脑细胞凋亡级联反应中起作用。