BACKGROUND Intracellular acidosis in the ischemic penumbra can contribute to further cell death, effectively enlarging the infarct core. Restoring the acid-base balance may enhance tissue survivability after cerebral ischemia. OBJECTIVE This study investigated whether translocating protons out of penumbral neurons could mitigate tissue acidification and induce neuroprotection in a rodent model of acute cerebral ischemia. METHODS We modulated the penumbral neurons via a light-driven pump to translocate protons out (i.e., archaerhodopsin/ArchT group) or into (i.e., channelrhodopsin-2/ChR2 group) neurons after focal cerebral ischemia in rats. Intracellular pH values were imaged via neutral red (NR) fluorescence and cerebral blood flow (CBF) was monitored through laser speckle contrast imaging (LSCI). Global CBF responses to electrical stimulation of the hindlimbs were obtained 24 h and 48 h after ischemia to assess neurological function. Behavioral and histological outcomes were evaluated 48 h after ischemia. A control group without gene modification was included. RESULTS The reduction of relative pH (RpH), the amplitude of negative peak of hypoemic response (RNP) and the hemispheric lateralization index (LI) in ArchT group were significantly less than those of the ChR2 or control group. Moreover, RpH was strongly correlated with RNP (r = 0.60) and LI (r24h = 0.80, r48h = 0.59). In addition, behavioral and histological results supported a neuroprotective effect of countering neuronal acidosis in penumbra through optogenetic stimulation. CONCLUSION(S) These results indicate that countering intracellular acidosis by optogenetically translocating protons out of penumbral neurons during the acute ischemic stage could induce protection after ischemic brain injury.

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半影神经元中质子的光遗传易位在局灶性脑缺血的啮齿动物模型中具有保护作用

背景缺血半暗带中的细胞内酸中毒可导致进一步的细胞死亡，有效地扩大梗塞核心。恢复酸碱平衡可以提高脑缺血后组织的生存能力。目的 本研究调查了从半影神经元转位质子是否可以减轻急性脑缺血啮齿动物模型中的组织酸化并诱导神经保护作用。方法我们通过光驱动泵调节半影神经元，以在大鼠局灶性脑缺血后将质子移出（即古视紫质/ArchT 组）或移入（即通道视紫红质-2/ChR2 组）神经元。通过中性红 (NR) 荧光成像细胞内 pH 值，并通过激光散斑对比成像 (LSCI) 监测脑血流量 (CBF)。在缺血后 24 小时和 48 小时获得对后肢电刺激的整体 CBF 反应，以评估神经功能。缺血后 48 小时评估行为和组织学结果。包括没有基因修饰的对照组。结果 ArchT组相对pH值(RpH)、低血反应负峰(RNP)幅度和半球偏侧化指数(LI)的降低均​​显着小于ChR2组或对照组。此外，RpH 与 RNP (r = 0.60) 和 LI (r24h = 0.80, r48h = 0.59) 密切相关。此外，行为和组织学结果支持通过光遗传学刺激对抗半暗带神经元酸中毒的神经保护作用。