Differences in neuronal damage and gliosis in the hippocampus between young and adult gerbils induced by long duration of transient cerebral ischemia.

Abstract: Response to cerebral ischemia in young animals was very different from that in the adult. The aim of this study was to investigate differences in neuronal death and gliosis in the hippocampal CA1 region (CA1) between adult and young gerbils following 5 and 15min of transient cerebral ischemia. Delayed neuronal death (DND) of pyramidal cells occurred in the CA1 was similar in all the adult gerbils after 5 and 15min of ischemia: the DND occurred 4days after ischemia. In the young groups, DND of pyramidal cells in the CA1 region occurred 7 and 3days after 5 and 15min of ischemia, respectively. On the other hand, the activation of GFAP-immunoreactive (+) astrocytes and Iba-1+ microglia was different in the young groups from the adult groups after ischemia. The change pattern of GFAP immunoreactivity in the adult groups was similar in both the adult groups after ischemia; in the young groups, the activation of GFAP+ astrocytes after 5min of ischemia was much delayed than that after 15min of ischemia. Activated Iba-1+ microglia were aggregated in the stratum pyramidale 4days after ischemia in all the adult ischemia-operated groups; in the young groups, activated Iba-1+ microglia were aggregated in the stratum pyramidale 7days after 5min of ischemia and 3days after 15min of ischemia. These observations indicate that DND in young animals is very different from the adult according to different duration of transient cerebral ischemia and glial activation is very different in young animals after different duration of transient ischemia. [Copyright &y& Elsevier]