EMBRYONIC TRANSPLANTATION AND ISCHEMIC MEMORY DEFICIT

Transient forebrain ischemia is associated with selective neuronal vul nerability and persistent memory deficit. This study compares function al outcome and morphological changes in rats subjected to post-ischemi c CA1 or hilus/dentate gyrus region hippocampal fetal transplantation. Ischemia was produced by bilateral common carotid artery occlusion wi th hypotension. Fetal hippocampal neurons were transplanted into both sides of the CA1 or hilus/dentate gyrus region of the dorsal hippocamp us, 1 week post-ischemia. Four weeks post transplantation, the rats un derwent behavioral testing for 5 consecutive days using the water maze trial. All animals were perfusion fixed for morphological studies. Tr ansplants in the CA1 region of the dorsal hippocampus were associated with memory and morphological recovery, while grafts placed into the h ilus/dentate gyrus region of the dorsal hippocampus were not. Similarl y, neurons transplanted in the CA1 region of the dorsal hippocampus we re morphologically similar to CA1 pyramidal cell neurons and stained p ositive with calbindin D-28k. In contrast the grafts transplanted into the hilus/dentate gyrus region of the dorsal hippocampus were morphol ogically heterogeneous and staining with calbindin D-28k was not as ro bust. Post-ischemic transplantation in the CA1 region of the dorsal hi ppocampus is effective in improving memory and morphological function. (C) 1997 Elsevier Science Ireland Ltd.