Research on blood-brain barrier of estrogen in rats after cerebral ischemia-reperfusion / 局解手术学杂志

ABSTRACT

Objective To observe the effect of estrogen on BBB permeability,occludin expression after ischemia-reperfusion in rats,and to make a further investigation on the role of estrogen in cerebral ischemia. Methods Ovariectomized rats were randomly divided into sham-operated group,model group,and estrogen pretreatment group. 4 h,24 h,3 d after ischemia-reperfusion were selected as different observation points,and changes of edema,occluding expression,and blood-brain barrier permeability of the 3 points in time were observed. BBB ultra-structure electron microscope observation was made at 24 h and 3 d after ischemia-reperfusion. Changes in cerebral edema were measured by brain water content percentage;protein expressions were measured by Western blot;and BBB permeability was measured by Evans blue as-say. Results Compared with the sham group,brain tissue water content and EB content in model group both increased 4 h after ischemia-reperfusion (P0. 05). 24 h after ischemia-reperfusion,the occludin expression were weaker than that in the sham surgery group with a significant difference (P0. 05). In estrogen group,there was significant difference in occludin protein expression at 24 h and 3 d after ischemia-reperfusion compared with model group at the same time point (P<0. 05). Conclusion BBB ultrastructure disclose TJ was broke and vesicles within EC was increased and astrocyte cell foot process was swelling in MCAO model,it might be the vasogenic brain edema pathological basis for MCAO. In MCAO animal model,with ischemia-reperfusion time increasing,TJ protein occludin expression significantly decreased,it suggests that occludin plays an important role in the regulation of TJ permeability. Estrogen increases has a very close relationship with occludin ex-pression,and it may be one of the mechanisms of protecting BBB integrity and lessening cerebral edema.