RESISTANCE TO BRAIN DAMAGE OF
PROLONGED SEIZURE IN RATS WITH DIFFERENT MATURATIONAL STAGES
JIANG L, CAI FC, ZHANG XP
Children’s Hospital, Chongqing University of Medical Sciences,
Chongqing, China,
Objective: To demonstrate the special ability to resist brain
damage from prolonged seizures and convulsive status epilepticus(SE) in
premature animal.
Methods: Megimide was injected in 80 healthy and adult rats
respectively to evoke prolonged seizures and SE. The incidences of injured
neurons were analyzed at the slices of hippocampus CA3, dentate gyrus and
parietal cortex.
Results: (1) Adults rats (ARs) only had less than 20 minutes’
prolonged seizures with the same dose of megimide, however 71.4% baby rats
(BRs) experienced SE. (2) The average duration from the onset to death
during the period of seizure was 44±24min in BRs, and 7±5min
in ARs. (3) Comparing the incidences of died neurons at different cortical
areas, it was shown a typical pathologically pattern of selective neuron
damage predominately at hippocapus and dentate gyrus. (4) On the 4th
day after seizure in BRs, the number of necrosis neurons counted from
hippocampus, dentate gyrus was 60±21 cells in the group with
seizure lasting ≤29min;167±51
cells with seizure lasting 30±59min.
However there were 227±34min of necrosis neurons in ARs although their
seizure lasting ≤20min only. The number of died neurons could be
equal between ARs and BRs only when the seizures of BRs was lasting
>60min.
Conclusion: (1) Premature brain was more like to have prolonged
seizure or SE than adults. (2) There were great difference of the
resistance to brain damage from sever seizure between premature and mature
brain, the more premature the more resistant; (3) Brain damage induced by
sever seizure was characteristically as selected neuron loss predominantly
at hippocampus, dentate gyrus. (4) Prolonged SE, particularly more than
60min, could also induce brain injury in BRs although their much stronger
resistance to the injury.