Alterations of a 200 kDa Neurofilament in the Rat Hippocampus after Forebrain Ischemia

Alteration in the concentration of a 200 kDa neurofilament (NF200) in the rathippocampus after forebrain ischemia and its relationship to hippocampalneuronal death were studied with an anti-200 kDa neurofilament antibody, usingimmunohistochemical and immunoblotting techniques. In rats subjected to 8 min oftransient forebrain ischemia, hematoxylin-eosin staining showed survival of mostof the neurons in the hippocampal CA1 region at 1 day and loss of more than 75%of the neurons at 7 days after ischemia. Immunoblotting showed that theconcentration of NF200 in the hippocampal homogenate tended to decrease afterischemia, to 69% of that of control at 1 day and to 60% of the control value at7 days after 8 min of forebrain ischemia. Following 5 min of ischemia as well,the decrease in the concentration of neurofilaments in the hippocampal regionpreceded histological confirmation of neuronal cell death. These results suggestthat degradation of neurofilament triplet proteins occurred even after ischemiaof minimal duration and preceded neuronal death. Degradation of cytoskeletalproteins may play an important role in the mechanism of delayed neuronal deathafter cerebral ischemia.