An Experimental Study of Variation in Brain Edema after the Focal Cerebral Ischemia in Rats

Objective To explore the dymamic variation in brain edema after the focal cerebral ischemia. Methods We determined changes of brain water content after middle cerebral artery occlusion (MCAO) .Twenty-eight normal SD rats(200～300g,female or male) were randomly divided into three groups:the normal group(n=4),the false operation group(n=4) and the ischemical injury group(n=20,each 4 of them were respctively observed at 2h,4h,8h,15h and 30h after MCAO). Results It was found that the water contents of brain tissues in normal group were similar to that in false operation group.In ischemical injury group,the contens were increasing from 2h after MCAO and had reached a top value at 8h (p0.05),then gradually decreased(p0.01).Conclusion The brain tissue edema appears from 2h after MCAO and reaches the top at 8h and then gradually decreases.