Figure 6.
Four days of rapid kindling results in neuronal death. Frozen brain sections isolated from four naive and three kindled animals were either stained with Fluoro-jade B, a marker for degenerating neurons (A, B, F, G, K), or immunostained for active caspase-3 (C–E, H–J, M–O). Representative images of Fluoro-jade staining from the ipsilateral hippocampus are shown [A, F (naive); B, G (kindled; four stage-V seizures)]. The region of the hippocampus from which the image is obtained is indicated to the left. Note the increase in staining in kindled animals. This increase is partly attributable to staining of neurons as shown in the inset in B and reactive astrocytes (taken from the hilus) as shown in K. FJ staining was also occasionally detected in the somatosensory cortex of a kindled animal (four stage-V seizures; L). No caspase-3 staining was detected in the animal experiencing four stage-V seizures (C, H). In contrast, a punctate pattern of staining was present in animals experiencing eight (D, I) and 16 (E, J) stage-V seizures. The significance of these puncta is currently unknown. Large circular blebs, consistent with the appearance of apoptotic bodies, are particularly abundant in the CA1 and hilus in the latter animal (E, J, arrowheads). K, Higher-magnification image of large blebs indicated by the arrow in E (blue, DAPI counterstain). M, A few active caspase-3 positive cells were present in the somatosensory cortex (only in the animal experiencing 16 stage-V seizures; blue, DAPI counterstain). N, O, Double immunofluorescent staining for C3 (green) and the neuronal marker NeuN (red); blue, DAPI counterstain. The image was taken from the granule cell layer border. Scale bars: (in A) A–E, 300 μm; (in F) F–J, 300 μm; K, N, O, 60 μm; L, M, 30 μm.