| Co-Investigator(Kenkyū-buntansha) |
OYANAGI Kiyomitsu Niigata Univ., Brain Research Inst., Assist.,, 脳研究所, 助手 (00134958)
TAKEDA Shigeki Niigata Univ., Brain Research Inst., Assist.,, 脳研究所, 助手 (90134957)
YOSHIDA Yasuji Niigata Univ., Brain Research Inst., Assist.,, 脳研究所, 助手 (70126465)
OHAMA Eisaku Niigata Univ., Brain Research Inst., Ass. Prof.,, 脳研究所, 助教授 (50018892)
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| Research Abstract |
Based on a chronological examination of cold lesions, we suggested that the condition, "edema", could be considered to be essential for lesion repair and that it is actually compatible to the physiolgical environment seen in the fetal developing brain (Acta Neuropathol. Suppl. VIII, 103, 1983).
We further studied the experimentally induced edema by various pathological factors including ischemia, trauma, intoxication (organic mercury) and viral infection (SSPE). On the edema and astrocyte activitites in the repair process, all of these lesions showed fundamentally same morphological alterations as those in the cold lesions.
In the first stage, neuronal degeneration and severe swelling of the astrocytes were noticed. In the second stage, when tissue damage was severe enough, hematogenous edema fluid permeated the extracellular space. Thus, all neurons and astrocytes were freely floating in the edema fluid, which provides a significant space for cell motility. In the third stage, macrophages appeared in the fluid and phagocytized necrotized cell debris. Simultaneously, the astrocytes showed mitosis and acquired the ability of motility. After all cell debris was removed, the lesions proceeded to the fourth and final stage of lesion repair. Surviving neurons, synapses and blood vessels were again covered by the processes of postmitotic "reactive" astrocytes.
In mild lesions, however, the first stage of swelling of the astrocytes continued and permeation of edema fluid was either not evident. The necrotized neurons appeared to be removed or digested mostly by the astrocytes.
Interestingly mitosis of the astrocytes was found in the lesions from the third to fourth day exclusively, regardless of the severity of the lesion.
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