Dynamic changes of bloodª²brain barrier permeability and S100B protein level in serum after acute cerebral ischemia/reperfusion in rats

    WU Songª²Di, WAN Qi, XIA Feng, GENG Xiaoª²Ying, LIU Xueª²Dong, WANG Jinª²Cun

    Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi¬ðan 710033, China, Department of Neurology, Xi¬ðan NO.1 Hospital, Xi¬ðan 710002,China

    ¡¾Abstract¡¿ AIM: To investigate the dynamic changes of the bloodª²brain barrier(BBB) permeability and the S100B protein level in serum after acute cerebral ischemia/reperfusion in rats. METHODS: The middle cerebral artery occlusion/reperfusion (MCAO/R) rat model was made by the thread occlusion method; the permeability of BBB was investigated by transmission electron microscope using lanthanum nitrate as the tracer; the serum S100B protein concentrations were determined by ELISA at 0.5, 2, 6, 12, 24 and 48 h reperfusion after 2 h cerebral ischemia. RESULTS: ¢Ù Electron microscopy revealed that lanthanum granules appeared around the tight junction and in the endotheliocytes at 0.5 h areperfusion, indicating the increase of BBB permeability. More phagotrophic lanthanum granules were found in the endotheliocytes that showed significant vacuolization at 2 and 6 h. The tight junction was opened and the astrocytes were separated from the basement membrane of the capillaries. The necrosis of both neurons and astrocytes with dissolved nucleus and the disruption of the capillary basement membrane were found at 12 and 24 h. The necrosis and disaggregation of many neurons and astrocytes were evident at 48 h. A lot of lanthanum granules were shown outside the brain vessels while many endotheliocytes were broken. ¢Ú The serum S100B protein level increased significantly only in rats after cerebral ischemia/reperfusion injury, but not in the shamª²operation and the nonª²operation control rats (P<0.01). The serum concentration of S100B protein started to increase at 0.5 h of reperfusion. It kept at a high level until a peak appeared at 24 h. The serum S100B protein was maintained at a high level constitutively even at 48 h. CONCLUSION: The dynamic change of the S100B protein level in serum after ischemia/reperfusion reflects the change of the permeability of BBB. S100B can therefore be used as a peripheral biochemical marker to assess the permeability of BBB. ......