Superoxide radical generation and histopathological changes in hippocampal CA1 after ischaemia/ reperfusion in gerbils

Abstract

Toshimitsu Kitajima MDPurpose: We investigated the relationship between the generation of superoxide radicals and histopathological changes on delayed neuronal death in the hippocampal CA I subfield. Methods: Seventy gerbils were randomly assigned to two groups, a sham group and an ischaemia/reperfusion (I/R) group. In the I/R group, transient forebrain ischaemia was induced by occluding the bilateral common carotid arteries for four minutes. The cerebrum was removed after reperfusion at intervals of one minute, six, twelve and twentyfour hr and at three, five and seven days. Each forebrain was cut into two portions including the hippocampus. The quantity of superoxide radicals was measured by using chemiluminescence, and histopathological changes in the hippocampal CAI subfield were examined. Results: In the I/R group, superoxide radicals increased on the 3rd and 5th days compared with the sham group (16.1 ___ 3.4 vs 3.2 ___ 1.0 onthe third day(P < 0.0001); 10.9 + 1.9 vs 3.3 ___ 0.8 onthe fifth day (P < 0.0001)). In the I/R group, the pyramidal cells were atrophic and pycnotic; vacuolation, and structural disruption of the radial striated zone were observed from the third through the seventh day. In the sham group, these changes were not observed. There were differences of degenerative ratios in the pyramidal cells between the two groups from the third to seventh days (5.6 • 2.0 vs 80.9 +_ 3.3 on the third day (P < 0.05); 6.9 +--0.4 vs 93.6 ---2.4 on the fifth clay (P < 0.05); 6.2 _ 1.5 vs 95.0 ___ 1.3 on the seventh day (P < 0.05)). Condusion: There is a correlation between the generation of superoxide radicals and histopathological changes of the pyramidal cells in the hippocampal CAI subfield.Objectif: Investiguer la relation entre la production des radicaux superoxydes et les changements histopathologiques sur led&& neuronal retard~ darts le champ hippocampique CAl. M&hodes : Soixante-dix gerbilles ont ~t~ al6atoirement r~parties en 2 groupes, un groupe contr61e et un groupe isch~mie/reperfusion (I/R). Darts le groupe I/R, une isch~mie transitoire du prosenc6phale 6tait induite par rocclusion bilat&ale des carotides communes pour quatre minutes. Apr~s reperfusion, le cerveau ~tait retir~ de l'animal apr~s une minute de m~.me qu'~ six, douze et vingt-quatre heures ainsi qu'~ trois, cinq et sept jours. Chaque prosenc~phale ~tait coup~ en deux parties incluant l'hippocampe. La quantit6 de radicaux superoxydes &ait mesur& par chemiluminescence et les changements histopathologiques dans le champ hippocampique C.AI ~taient observ&. R&ultats : Darts le groupe I/R, les radicaux superoxydes ont augment~ aux jours 3 et 5 comparativement au groupe t~moin (I 6, I ---3,4 vs 3,2 + 1,0 au jour 3 (P<0,0001); 10,9 + 1,9 vs 3,3 ---0,8 au jour 5 (m<0,0001)). Darts le groupe I/R, les cellules pyramidales ~taient atrophiques et picnotiques; du 3e au 7e jour, on a observ~ de la vacuolisation et de la destruction structurale de la zone stri~e radiaire, et ces changements n'ont pas &6 retrouv& darts le groupe t~moin. On a observ~ ...

Dehydroepiandrosterone prevents oxidative injury induced by transient ischemia/reperfusion in the brain of diabetic rats.

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