Moolman J A, Genade S, Tromp E, Opie L H, Lochner A
Department of Internal Medicine, University of Stellenbosch.
S Afr Med J. 1997 Jun;87 Suppl 3:C151-6.
Because ischaemic preconditioning elicits a potent endogenous protective mechanism against the development of myocardial infarction, it is important to explore its utilisation in clinical situations. The aim of this study was to examine whether the myocardium of rats with genetic hypertension could be protected by ischaemic preconditioning.
Male New Zealand genetically hypertensive rats (GH-Wistar-derived) and normotensive Wistar controls (WAG-Wistar-derived), aged 12 months, were used. Isolated perfused hearts were preconditioned by 3 periods of 5 minutes' global ischaemia, interspersed with 5 minutes' reperfusion, and subsequently subjected to 25 minutes' global ischaemia, followed by 30 minutes' reperfusion.
Heart and body mass were significantly higher in GH rats. Although the heart/body mass ratios of GH rats were higher than those of WAG rats, the difference was not significant. The reperfusion coronary flow pattern during the preconditioning protocol differed markedly between the 2 groups. Only normotensive WAG hearts demonstrated protective effects of preconditioning on post-ischaemic function and tissue creatine phosphate content, while the GH hearts could not be preconditioned.
An explanation for the failure of preconditioning in GH hearts is not yet available. The data caution against implementation of preconditioning in patients with angina pectoris and left ventricular hypertrophy.
由于缺血预处理可引发强大的内源性心肌梗死发展保护机制，因此探索其在临床中的应用具有重要意义。本研究旨在检测基因性高血压大鼠的心肌是否能通过缺血预处理得到保护。
使用12月龄雄性新西兰基因性高血压大鼠（源于GH-Wistar）和血压正常的Wistar对照大鼠（源于WAG-Wistar）。离体灌注心脏先进行3次5分钟全心缺血预处理，每次缺血期间穿插5分钟再灌注，随后进行25分钟全心缺血，再进行30分钟再灌注。
GH大鼠的心脏和体重显著更高。虽然GH大鼠的心脏/体重比高于WAG大鼠，但差异不显著。两组在预处理方案期间的再灌注冠脉血流模式明显不同。只有血压正常的WAG心脏表现出预处理对缺血后功能和组织磷酸肌酸含量的保护作用，而GH心脏无法进行预处理。
目前尚无法解释GH心脏预处理失败的原因。这些数据警示心绞痛和左心室肥厚患者不宜采用预处理。
