THE MECHANISM OF THE EXPRESSION OF TOLERANCE FOR ISCHEMIA BY ISCHEMIC PRECONDITIONING IN FETAL BRAIN.

[目的]探讨缺血预适应与胎脑缺血耐受的关系，探讨缺血预适应在胎脑对缺血耐受性的表达机制。[方法]采用反复脐带结扎的方法进行缺血预适应，再用腺苷激动剂和拮抗剂分别与不加用腺苷激动剂和拮抗剂诱导胎羊胎脑缺血缺氧。[结果]缺血预适应可提高胎脑对缺血的耐受性，腺苷激动剂可部分增强缺血耐受，腺苷拮抗剂可部分抑制缺血耐受。[结论]缺血预适应可诱导胎儿脑缺血耐受，这种耐受至少部分受腺苷调节。

[PURPOSE] The purpose of this study is to examine the relationship between ischemic preconditioning and ischemic tolerance in fetal brain, and evaluated the mechanism of the expression of the tolerance for ischemia by ischemic preconditioning.[METHOD] We performed ischemic preconditioning by repeated umbilical cord occlusion, and then inducted fetal brain ischemia and hypoxia by repeated umbilical cord occlusion in ten chronically instrumented fetal sheep with and without adenosine agonists and antagonists.[RESULTS] Fetal brain tolerance for ischemia was enhanced by ischemic preconditioning, which was partially augmented by adenosine agonists and diminished by adenosine antagonists.[CONCLUSION] Ischemic preconditioning elicits fetal brain tolerance for ischemia, which was at least in part regulated by adenosine.