Buckley Kathleen M, Hess Daniel L, Sazonova Irina Y, Periyasamy-Thandavan Sudharsan, Barrett John R, Kirks Russell, Grace Harrison, Kondrikova Galina, Johnson Maribeth H, Hess David C, Schoenlein Patricia V, Hoda Md Nasrul, Hill William D
Charlie Norwood VA Medical Center, Augusta, GA, USA ; Department of Cellular Biology & Anatomy, Georgia Regents University, Augusta, GA, USA.
The University of Virginia, School of Medicine, Charlottesville, VA, USA.
Exp Transl Stroke Med. 2014 Jun 21;6:8. doi: 10.1186/2040-7378-6-8. eCollection 2014.
BACKGROUND AND PURPOSE: The role of autophagy in response to ischemic stroke has been confusing with reports that both enhancement and inhibition of autophagy decrease infarct size and improve post-stroke outcomes. We sought to clarify this by comparing pharmacologic modulation of autophagy in two clinically relevant murine models of stroke. METHODS: We used rapamycin to induce autophagy, and chloroquine to block completion of autophagy, by treating mice immediately after stroke and at 24 hours post-stroke in two different models; permanent Middle Cerebral Artery Ligation (MCAL), which does not allow for reperfusion of distal trunk of middle cerebral artery, and Embolic Clot Middle Cerebral Artery Occlusion (eMCAO) which allows for a slow reperfusion similar to that seen in most human stroke patients. Outcome measures at 48 hours post-stroke included infarct size analysis, behavioral assessment using Bederson neurological scoring, and survival. RESULTS: Chloroquine treatment reduced the lesion size by approximately 30% and was significant only in the eMCAO model, where it also improved the neurological score, but did not increase survival. Rapamycin reduced lesion size by 44% and 50% in the MCAL and eMCAO models, respectively. Rapamycin also improved the neurological score to a greater degree than chloroquine and improved survival. CONCLUSIONS: While both inhibition and enhancement of autophagy by pharmacological intervention decreased lesion size and improved neurological scores, the enhancement with rapamycin showed a greater degree of improvement in outcomes as well as in survival. The protective action seen with chloroquine may be in part due to off-target effects on apoptosis separate from blocking lysosomal activity in autophagy. We conclude pharmacologic induction of autophagy is more advantageous than its blockade in physiologically-relevant permanent and slow reperfusion stroke models.
背景与目的:自噬在缺血性卒中反应中的作用一直存在争议,有报道称增强和抑制自噬均可减小梗死体积并改善卒中后结局。我们试图通过比较两种临床相关的小鼠卒中模型中自噬的药物调节作用来阐明这一问题。 方法:我们使用雷帕霉素诱导自噬,使用氯喹阻断自噬的完成,在两种不同模型中于卒中后即刻及卒中后24小时对小鼠进行治疗;永久性大脑中动脉结扎(MCAL)模型,该模型不允许大脑中动脉远端主干再灌注,以及栓塞性大脑中动脉闭塞(eMCAO)模型,该模型允许缓慢再灌注,类似于大多数人类卒中患者的情况。卒中后48小时的结局指标包括梗死体积分析、使用贝德森神经评分进行行为评估以及生存率。 结果:氯喹治疗使梗死体积减小约30%,且仅在eMCAO模型中具有显著性,在该模型中它还改善了神经评分,但未提高生存率。雷帕霉素在MCAL模型和eMCAO模型中分别使梗死体积减小44%和50%。雷帕霉素还比氯喹更大程度地改善了神经评分并提高了生存率。 结论:虽然通过药物干预抑制和增强自噬均可减小梗死体积并改善神经评分,但雷帕霉素增强自噬在结局以及生存率方面显示出更大程度的改善。氯喹所见的保护作用可能部分归因于对凋亡的非靶向效应,而非阻断自噬中的溶酶体活性。我们得出结论,在生理相关的永久性和缓慢再灌注卒中模型中,药物诱导自噬比阻断自噬更具优势。
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