Research Institute of Chemical Biology, Ilia State University, Tbilisi, Georgia.
Department of Anatomy, Tbilisi State Medical University, Tbilisi, Georgia.
Bull Exp Biol Med. 2022 Mar;172(5):602-607. doi: 10.1007/s10517-022-05438-x. Epub 2022 Mar 30.
We studied changes in the ultrastructure of synapses and myelin nerve fibers that develop in the penumbra in 4 and 12 h and 2 and 4 days after modeling infarction in the frontoparietal cortex in rats. Ischemic stroke was induced by injection of a photosensitive dye into their bloodstream followed by illumination of the brain surface with a halogen lamp. Visible ultrastructural changes were observed in the penumbra zone, namely in the axodendritic and axospinous synapses; they consisted in polymorphism and disorganization of synaptic vesicles, mitochondrial swelling, swelling and vacuolization of the postsynaptic fragments of dendrites, and shortening and osmiophilia of the active zone. In the presynaptic terminals, clear-cut signs of transformation were observed only in 2 and 4 days after infarction modeling. These terminals were located at the ends of the degenerated myelinated axons of necrotic neurons. These findings demonstrate irreversible changes in the ultrastructure of synapses in the penumbra in 2-4 days after infarction and indicate the necessity of early treatment of strokes.
我们研究了在大鼠额顶叶皮质梗死模型建立后 4 小时、12 小时、2 天和 4 天，半影区突触和髓鞘神经纤维的超微结构变化。通过将光敏染料注入其血流中并随后用卤素灯照射大脑表面来诱导缺血性中风。在半影区观察到明显的超微结构变化，即在轴突-树突和轴突-棘突突触中；它们包括突触小泡的多态性和紊乱、线粒体肿胀、树突突触后片段的肿胀和空泡化，以及活性区的缩短和嗜锇性。在 2 天和 4 天的脑梗死模型建立后，仅在前突触末端观察到明显的转化迹象。这些末端位于坏死神经元的退化有髓轴突的末端。这些发现表明，在脑梗死发生后 2-4 天，半影区突触的超微结构发生了不可逆转的变化，这表明有必要对中风进行早期治疗。
