Abstract: ［Abstract］ Objective〖HTSS〗〓To investigate whether Edaravone has a protective effect in model for newborn rats of hypoxicischemia brain damage.
〖HTH〗〖WTHZ〗Methods〖HTSS〗〓Sevendayold(P7) SD rats 48 were randomly divided into 3 groups(n=16, each group):  control group(group S), hypoxiaischemia brain group(group R), edaravone group(group F). P7 rats were subjected to hypoxiaischemia brain damage for 2 h. Edaravone was treated after hypoxicischemia brain damage in group F. After 24h, neurological deficit scores were assessed. Matrix metalloprotein9（MMP9） was detected by enzymelinked immunosorbent assay in the ischemic penumbrae of the cerebral cortex. The nervous structure was detected by electron microscopic observation. The content of Evans blue（EB） in the brain of neonatal rats was determined.
〖HTH〗〖WTHZ〗Results〖HTSS〗〓MMP9, EB, S score in group R were higher than that of group S. Turn over times in group R were less than that of group S. MMP9, EB, S score in group F were lower than that of group S. Turn over times in group R and group F were less than that of group S. Turn over times in group R were less than that of group F. The differences were statistically significant（P＜005）. There is one death of rat in group R, and no death in group F and S.
〖HTH〗〖WTHZ〗Conclusion〖HTSS〗〓The expression of MMP9 in brain tissue of neonatal rats with cerebral ischemia and hypoxia was increased, and the permeability of blood brain barrier was increased. Edaravone treatment provides neuroprotection against cerebral ischemia and hypoxia in neonatal rats by protecting blood brain barrier permeability, improving neurological function. The mechanisms for the effect might be related to the inhibition of MMP9 expression in cerebral ischemia and hypoxia in neonatal rats.

Key words: brain ischemia, bloodbrain barrier, matrix metalloproteinase 9