Abstract：
Mitochondrial function is tightly linked to morphology, and fragmentation of dendritic mitochondria during noxious conditions suggests loss of function. In the normoxic cortex, spreading depolarization (SD) is a phenomenon underlying migraine aura. It is unknown whether mitochondria structure is affected by normoxic SD. In vivo two-photon imaging followed by quantitative serial section electron microscopy (ssEM) was used to monitor dendritic mitochondria in the normoxic cortex of urethane-anesthetized mature male and female mice during and after SD initiated by focal KCl microinjection. Structural dynamics of dendrites and their mitochondria were visualized by transfecting excitatory, glutamatergic neurons of the somatosensory cortex with bicistronic AAV, which induced tdTomoto labeling in neuronal cytoplasm and mitochondria labeling with roGFP. Normoxic SD triggered rapidly reversible fragmentation of dendritic mitochondria alongside dendritic beading; however, mitochondria took significantly longer to recover. Several rounds of SD resulted in transient mitochondrial fragmentation and dendritic beading without accumulating injury, as both recovered. SsEM corroborated normoxic SD-elicited dendritic and mitochondrial swelling and transformation of the filamentous mitochondrial network into shorter, swollen tubular, and globular structures. Our results revealed normoxic SD-induced disruption of the dendritic mitochondrial structure that might impact mitochondrial bioenergetics during migraine with aura.
摘要：
线粒体功能与形态学紧密相连,在有害条件下树突状线粒体的碎片表明功能丧失。在常氧皮质，扩散去极化（SD）是偏头痛先兆的潜在现象。线粒体结构是否受到常氧SD的影响尚不清楚。体内双光子成像，然后进行定量连续切片电子显微镜（ssEM），用于在局灶性KCl显微注射引发的SD期间和之后，监测尿烷麻醉的成熟雄性和雌性小鼠的常氧皮质中的树突状线粒体。通过转染兴奋性来可视化树突及其线粒体的结构动力学，具有双顺反子AAV的体感皮层的谷氨酸能神经元，其在神经元细胞质中诱导tdTomoto标记和线粒体用roGFP标记。常氧SD触发了树突状线粒体的快速可逆片段化以及树突状珠化；然而，线粒体需要更长的时间才能恢复。几轮SD导致短暂的线粒体片段化和树突状珠化而没有累积损伤，两人都康复了。SsEM证实了常氧SD引起的树突状和线粒体肿胀，并将丝状线粒体网络转化为较短的，肿胀的肾小管，和球状结构。我们的结果表明，常氧SD诱导的树突状线粒体结构破坏可能会影响先兆偏头痛期间的线粒体生物能学。
