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2006 Fiscal Year Final Research Report Summary

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

Research Project

Project/Area Number 17591143
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Embryonic/Neonatal medicine
Research InstitutionYamaguchi University

Principal Investigator

SAKATA Yoshiyuki  Yamaguchi University, Graduate School of Medicine, Assistant Professor, 大学院医学系研究科, 講師 (10034927)

Co-Investigator(Kenkyū-buntansha) NAKAMURA Shoji  Yamaguchi University, Graduate School of Medicine, Professor, 大学院医学系研究科, 教授 (80112051)
木田 裕之  山口大学, 大学院医学系研究科, 助手 (70432739)
Project Period (FY) 2005 – 2006
Keywordshypoxia / fetal brain / Bcl-2 / Bax / siRNA / caspase-3 / apoptosis / optical imaging
Research Abstract

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.

  • Research Products

    (1 results)

All 2006

All Journal Article (1 results)

  • [Journal Article] In vivo optical recordings of synaptic transmission and intracellular Ca^<2+> and Cl^- in the superior colliculus of fetal rats2006

    • Author(s)
      Yoshiyuki Sakata
    • Journal Title

      European Journal of Neuroscience 23

      Pages: 1405-1416

    • Description
      「研究成果報告書概要(和文)」より

URL: 

Published: 2008-05-27  

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