Observation of astrocyte proliferation and glial fibrillary acid protein expression for evaluating cerebral infarction

AIM: To observe the activity and distribution of astrocytes and glial fibrillary acid protein(GFAP) after middle cerebral artery occlusion (MCAO). METHODS: The rat MCAO model was made by two-kidney, tow clip renovascular hypertensive rat stroke prone(RHRSP). Rats were killed and brain samples were collected at the end of 1,3,6 and 9 weeks after MCAO, respectively. The ultrastructure of astrocytes was determined at broder of infarct (A area); distant of infarct (B area) and opposite of hemisphere (C area) by electron microscope. The number and optical density of GFAP-positive cells were also observed. RESULTS: The astrocyte proliferation distributed in the whole brain after MCAO. The highest numbers of GFAP-positive cells were observed at A area, then B area. The lowest numbers of GFAP positive cells were found in C area. The time course of GFAP-positive cell change was that the highest number was observed at 1 week after MCAO, then decreased by time from 3, 6 weeks to 9 weeks. The optical density of GFAP-positive cells showed the same patterns. CONCLUSION: The correlation between astrocyte proliferation and tissue damage after MCAO can be estimated by GFAP expression. The astrocyte proliferation plays an important role in healing process after MCAO.