Abstract: The tests adapted four-vessel occlusion model to study the different patterns of astrocytosis in post TIA rat hippocampal formation induced by a repeated transient cerebral ischemia. The astrocytes were identified by using an antibody against glial fibrillary acidic protein(GFAP). The morphological changes, distribution and time-course changes of reactive astrocytes were investigated after TIAs in the hippocampal formation. Reactive astrocytosis in CA1 and CA3 all attained highest peak at 7 d after reputation. The number, area and grey of astrocytes in CA1 were respectively 12.68±1.57,(123.90±19.39)μm², 113.20±18.76 at 7 d after reputation. Then its astrocytosis was lastly and no distinct with that at 30 d after reputation(P>0.05). The number, area and grey of astrocytes in CA3 were respectively 9.24±0.88,(113.60±18.87)μm², 96.61± 9.36 at 7 d after reputation. Astrocytosis in CA3 was brief and down quickly from 7 d to 30 d(P< 0.01).

Key words: transient ischemic attack, glial fabrillary acidic protein, astrocyte, blood-brain-barrier