Ultrastructural and MRI study of the substantia nigra evolving exofocal post-ischemic neuronal death in the rat.

摘要: To clarify the morphological characteristics of exofocal post-ischemic neuronal death (EPND) in substantia nigra (SN), we investigated course light- and electron-microscopic changes SN rats subjected to occlusion left middle cerebral artery (MCA) for 1, 2, 4, 7 12 days. assess cellular edema, sequential magnetic resonance (MR) mapping apparent diffusion coefficient (ADC) T2 value test was performed. Histological examination on day 1 showed dotted chromatin clumps nuclei some neurons mild swelling perivascular endfeet astrocytes ipsilateral SN. On a few cells pars reticulata (SNr) revealed key signs apoptosis--apoptotic body-like condensation segregation DNA fragmentation-like nuclear remnants. 38% became swollen (pale neurons) with cytoplasmic microvacuoles, which appeared originate from rough endoplasmic reticulum (rER), mitochondria Golgi apparatus. Twenty percent massive proliferation cisternae rER, were fragmented or had lost their normal parallel arrangement. In addition, MR transient ADC decrease increase (signifying phase edema), coordinated ultrastructural swelling. Further, total number started gradually, markedly swollen, neuropil loose 4. 7, reactive dark occurred most frequently. These results suggest that EPND after MCA adult is due both apoptosis necrosis, although necrosis seems be dominant mechanism EPND. However, morphologic resemblances delayed these processes have common pathomechanism.