Influence of glucocorticoid on ischemia-induced neuronal damage in gerbil hippocampus

Objective To investigate the effect of glucocorticoid on ischemia-induced neuronal damage in gerbil hippocampus with forebrain ischemia model.Methods Twenty-one gerbils were randomly assigned to 3 groups (7 animals each). The animal was anesthetized and both common carotid arteries were exposed and separated. Silk threads were looped around these arteries. In group A and group B ,10 μl saline was given and in group C dexamethasone-water soluble ( 3μg dissolved in 10 μl saline ) was administered intracerebroventricularly. After a stabilization period of 60 min, transient forebrain ishcmia for 2.5 min was induced in group B and group C by pulling the arteries with 8g weights under the brain temperature of 37.5℃±0.2℃. Seven days after the ischemia, the brains were taken out and fixed with 10% buffered formalin. Brain slices, 5 μm thick, were stained with hematoxylin and eosin. The numbers of preserved pyramidal cells in the hippocampal CA1 field per 1 mm length of stratum pyramidal were counted.Results (1) Compared with those in group A, the preserved pyramidal cells in hippocampal CA1 field were reduced in group B and group C (P0.01). (2) The preserved pyramidal cells in group C were fewer than those in group B (P0.01).Conclusions Transient forebrain ischemia for 2.5 min can produce a marked damage in the hippocampal CA1 region. Glucocorticoid produce deleterious effect on ischemia-induced injury of hippocampal neurons in vivo.