Prolonged and extensive IgG immunoreactivity after severe fluid-percussion injury in rat brain.
The relationships between protein extravasation, morphological changes in neurons, and reactive changes in axons were evaluated in rats subjected to right lateral fluid-percussion injury to the brain (4.8-5.6 atm, 20 ms). Serial sections of the brain were immunostained with antibodies to rat immunoglobulin G (IgG) and 68-kDa neurofilament at 1 h to 2 weeks after injury or sham injury. Ischemic changes in neurons were noted in the injured cortex at 6-48 h after injury, and macroscopic hemorrhages were noted in the right corpus callosum and external capsule at 1 h to 1 week after injury. Extracellular IgG immunostaining was observed in the right cortex and right hippocampus at 1 h to 1 week after injury, and in the cortices and hippocampi bilaterally at 2 weeks after injury, but was most prominent in those regions at 24 h after injury. Intracellular IgG staining was noted in the neurons of cortices, hippocampi, brainstem, and cerebellum at 1 h to 2 weeks after injury. The number of IgG immunoreactive neurons was greatest at 1 week after injury. Thickened IgG immunoreactive axons and reactive axonal changes seen with neurofilament immunostaining were both in the similar region of the brainstem at 1 h to 1 week after injury. It appears that prolonged and widespread breakdown of the blood-brain barrier to plasma protein occurs after severe concussive brain injury and that this breakdown is not always accompanied by morphological changes. Intra-axonal IgG immunostaining provides additional clues to the pathogenesis of axonal damage following diffuse brain injury.
Hoshino
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Department of Neurosurgery, Nippon Medical School, Chiba Hokusoh Hospital, Japan.
Kobayashi
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Nakazawa
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D000818:Animals; D001369:Axons / Q000502:physiology*; D001812:Blood-Brain Barrier / Q000502:physiology*; D001930:Brain Injuries / Q000473:pathology*; D002540:Cerebral Cortex / Q000276:immunology*; D004195:Disease Models, Animal; D007074:Immunoglobulin G / Q000032:analysis*; D007150:Immunohistochemistry; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D007074:Immunoglobulin G