Simultaneous monitoring of intracellular pH changes and hemodynamic response during cortical spreading depression by fluorescence-corrected multimodal optical imaging
Simultaneous monitoring of intracellular pH changes and hemodynamic response during cortical spreading depression by fluorescence-corrected multimodal optical imaging
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DOI：
10.1016/j.neuroimage.2011.05.040
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发表时间：
2011-08
期刊：
影响因子：
5.7
通讯作者：
Xiaoli Sun;Yaru Wang;Shangbin Chen;Weihua Luo;Pengcheng Li;Qingming Luo
中科院分区：
文献类型：
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作者：
Xiaoli Sun;Yaru Wang;Shangbin Chen;Weihua Luo;Pengcheng Li;Qingming Luo
皮层扩张性抑制（CSD）在创伤、偏头痛和缺血中起重要作用。CSD可以引起明显的血流动力学变化和pH稳态的紊乱，这被认为是导致缺血后细胞死亡的原因。在这项研究中，我们描述了一种荧光校正的多模态光学成像系统，可以同时监测CSD相关的细胞内pH （pHi）变化和血液动力学反应，包括血红蛋白浓度和脑血流量（CBF）。用KCl刺激大鼠皮层诱发脑电，记录直流电位是脑电的典型特征。pHishift用中性红（NR）荧光进行定位，激发波长为516 ~ 556nm，发射波长为625nm。采用双波长光学本征信号成像（OISI）在550nm和625nm处测定血红蛋白浓度的变化。通过配备液晶可调滤波器（LCTF）的分时相机实现了荧光成像和双波长OISI的集成。采用激光散斑对比成像（LSCI），通过单独的相机观察脑血流。此外，基于系统获得的双波长光学本征信号（OISs），根据我们的荧光校正方法对NR荧光进行校正。我们发现在CSD期间发生了短暂的细胞内酸化，随后发生了小的碱化。CSD后细胞内酸化时间延长，ph恢复时间远长于血流动力学反应时间。我们的研究结果表明，新的多模态光学成像系统有可能推进我们对CSD的认识，并可能作为一种有用的工具来研究生理和病理条件下的神经血管耦合。
Cortical spreading depression (CSD) plays an important role in trauma, migraine and ischemia. CSD could induce pronounced hemodynamic changes and the disturbance of pH homeostasis which has been postulated to contribute to cell death following ischemia. In this study, we described a fluorescence-corrected multimodal optical imaging system to simultaneously monitor CSD associated intracellular pH (pHi)changes and hemodynamic response including hemoglobin concentrations and cerebral blood flow (CBF). CSD was elicited by application of KCl on rat cortex and direct current (DC) potential was recorded as a typical characteristic of CSD. The pHishift was mapped by neutral red (NR) fluorescence which was excited at 516–556nm and emitted at 625nm. The changes in hemoglobin concentrations were determined by dual-wavelength optical intrinsic signal imaging (OISI) at 550nm and 625nm. Integration of fluorescence imaging and dual-wavelength OISI was achieved by a time-sharing camera equipped with a liquid crystal tunable filter (LCTF). CBF was visualized by laser speckle contrast imaging (LSCI) through a separate camera. Besides, based on the dual-wavelength optical intrinsic signals (OISs) obtained from our system, NR fluorescence was corrected according to our method of fluorescence correction. We found that a transient intracellular acidification followed by a small alkalization occurred during CSD. After CSD, there was a prolonged intracellular acidification and the recovery of pHifrom CSD took much longer time than those of hemodynamic response. Our results suggested that the new multimodal optical imaging system had the potential to advance our knowledge of CSD and might work as a useful tool to exploit neurovascular coupling under physiological and pathological conditions.