Selective vulnerability of hippocampal CA3 neurons to hypoxia after mild concussion in the rat.
Immunohistochemical staining for microtubule-associated protein 2 (MAP2) and synaptophysin was used to investigate the effect of hypoxia on hippocampal neurons after mild concussion in the rat. Male Sprague-Dawley rats were divided into four groups: Group 1 (n = 3) was subjected to a mild impact-acceleration closed head injury, group 2 (n = 3) was subjected to 30 min of moderate hypoxia, group 3 (n = 5) was subjected to head trauma followed by 30 min of moderate hypoxia, and group 4 (n = 3) comprised sham-operated controls. All rats were fixed by transcardial perfusion 24 h after insult. No damage was observed in CA1 or CA2 neurons in any of the rats. However, rats in group 3 showed selective damage of hippocampal CA3 neurons manifested by a pycnosis and a marked decrease in MAP2 immunoreactivity. Presynaptic terminals visualized by synaptophysin immunostaining showed no differences among groups. The loss of immunoreactivity for the post-synaptic somal and dendritic protein marker MAP2 from the CA3 subfield 24 h after combined insults indicates an increased vulnerability of pyramidal cells in this brain area.
Nawashiro
H
H
Department of Neurosurgery, National Defense Medical College, Saitama, Japan.
Shima
K
K
Chigasaki
H
H
D000818:Animals; D001924:Brain Concussion / Q000150:complications / Q000378:metabolism / Q000473:pathology*; D006624:Hippocampus / Q000737:chemistry / Q000166:cytology*; D002534:Hypoxia, Brain / Q000209:etiology / Q000378:metabolism / Q000473:pathology*; D007150:Immunohistochemistry; D008297:Male; D009474:Neurons / Q000737:chemistry*; D051381:Rats; D017207:Rats, Sprague-Dawley