Kirkland Scott W, Coma Adrian K, Colwell Keri L, Metz Gerlinde A
Canadian Centre for Behavioural Neuroscience, University of Lethbridge, Lethbridge, AB, Canada.
Brain Res. 2008 Mar 27;1201:151-60. doi: 10.1016/j.brainres.2008.01.032. Epub 2008 Jan 26.
Stress might be one of the most salient intrinsic factors influencing the risk of stroke and its outcome. Previous studies have linked stress to increased infarct size and exaggerated cognitive deficits in rodent models of stroke. This study compares the effects of chronic restraint stress, representing a psychological stressor, prior to or after motor cortex devascularization lesion on motor recovery in rats. Daily testing in a skilled reaching task revealed initially exaggerated deficits in limb use caused by pre-lesion stress in the absence of increased infarct size. Both pre- and post-lesion stresses affected movement by delaying recovery and limiting compensation of lesion-induced deficits. Nevertheless, only rats that experienced post-lesion stress showed enlarged infarct size. This was accompanied by enlarged edema formation in the lesion hemisphere of post-stress animals on day 2 post-lesion. There were no significant differences in infarct size between post-lesion day 2 and day 15. The data demonstrate that both pre- and post-lesion chronic restraint stresses affect motor recovery after ischemic lesion. Lesion volume, however, is influenced by the timing of a stressful experience relative to the lesion. These findings suggest that stress represents a critical variable determining the outcome after stroke.
应激可能是影响中风风险及其预后的最显著内在因素之一。先前的研究已将应激与中风啮齿动物模型中梗死灶大小增加和认知缺陷加剧联系起来。本研究比较了代表心理应激源的慢性束缚应激在运动皮层缺血性损伤之前或之后对大鼠运动恢复的影响。在一项熟练抓握任务中的每日测试显示，在梗死灶大小未增加的情况下，损伤前应激最初会导致肢体使用方面夸张的缺陷。损伤前和损伤后应激均通过延迟恢复和限制对损伤诱导缺陷的代偿来影响运动。然而，只有经历损伤后应激的大鼠梗死灶大小增大。这伴随着应激后动物在损伤后第2天损伤半球水肿形成增大。损伤后第2天和第15天梗死灶大小无显著差异。数据表明，损伤前和损伤后慢性束缚应激均会影响缺血性损伤后的运动恢复。然而，损伤体积受相对于损伤的应激经历时间的影响。这些发现表明，应激是决定中风后预后的关键变量。
