心臟保護液在缺血性中風模式中的神經保護作用

Abstract

心臟保護液在心臟手術中是常見的藥物。其中Adenosine, lidocaine以及鎂離子(ALM)是非去極化心臟保護液體的其中一種配方。目前雖然知道ALM對心臟有保護的作用、但這樣的配方是否在神經系統也有保護作用則還沒有定論。因此這一研究探討低劑量的ALM是否能在神經系統缺血的時候達到神經保護的效果。我們使用細胞模式以及動物模式來驗證。在細胞模式中我們使用氯化鈷(CoCl2)來製造缺氧的環境，並以SH-SY5Y 細胞株來建立低糖低氧的模式。我們用不同濃度的ALM溶液 (1.0 mM adenosine, 2.0 mM lidocaine, and5 mM MgSO4)測試，並發現在. 2.5%, ALM 這個濃度下細胞因為缺氧而死亡的情形有顯著的改善。這個保護效果即使在缺氧持續1小時候才開始給予ALM也仍有保護的效果。在動物實驗上我們使用暫時性的腦缺血模式(transient middle cerebral artery occlusion)，來探討ALM保護液在生物體上的反應。我們用大鼠建立缺血性中風的模型，並隨機分派大鼠到實驗組 (ALM)和控制組(生理食鹽水)，並在腦部灌流停止的狀態下給予藥物。實驗結果顯示腦部缺血壞死的區域在實驗組(ALM)組有明顯的下降(5.0% ± 2.0% vs. 23.5% ± 5.5%, p=0.013)。神經學檢查也顯示和控制組相比實驗組的臨床表現較嚴重 (modified Longa score: 0 [0-1] vs.2 [1-2], p=0.047)。這些保護的效果也反映在血清中的神經細胞損傷標記，實驗組的濃度較低。這些結果提供ALM在缺血性中風的治療上可能有治療的潛力。

Adenosine, lidocaine, and magnesium (ALM) are cardioplegic solutions, which arrested heart contraction in high concentration. Whether low-dose ALM infusion was beneficial to ischemic brain has not been thoroughly investigated. In our study, we examined this issue in cell and animal models. We used cobalt chloride (CoCl2)-treated SH-SY5Y cells to mimic oxygen-glucose deprivation conditions in our cell model. SH-SY5Y cells were incubated with different dilutions of ALM authentic solution (1.0 mM adenosine, 2.0 mM lidocaine, and5 mM MgSO4 in Earle's balanced salt solution). ALM significantly reduced CoCl2-induced cell loss at a concentration of 2.5%. This protective effect persisted even when ALM was administered 1 h after the insult. As for animal model, we chose middle cerebral artery occlusion (MCAO) to mimic ischemic stroke status. We randomly assigned the rats into two groups—the experimental (ALM) and control (saline) groups—and infusion was administered during the ischemia: one hour in transient model and 6 hours in permanent model. In transient MCAO model, the infarction area was significantly reduced in the ALM group compared with the control group (5.0% ± 2.0% vs. 23.5%±5.5%, p=0.013). Neurological deficits were reduced in the ALM group compared with the control group (modified Longa score: 0 [0-1] vs.2 [1-2], p=0.047). This neuroprotective effect was substantiated by a reduction in the levels of various neuronal injury markers in plasma. In permanent MCAO model, ALM group had longer survival (hazard ratio was 9.95; 95% confidence interval: 1.61 to 61.9), but the infarction size was not reduced when compared to control group. The survival benefits might come from less brain edema. These results demonstrate the neuroprotective effects of ALM and may provide a new therapeutic strategy for ischemic stroke.