人工合成E-选择素对大鼠脑缺血再灌注损伤后血脑屏障的影响

目的探讨人工合成E-选择素对局灶性脑缺血再灌注损伤大鼠血脑屏障通透性以及紧密连接咬合蛋白和闭锁小带蛋白-1含量表达的影响。方法 180只SD大鼠随机分为假手术组(用线栓法将线栓插入颈内动脉及颈外动脉分叉处,其余操作同模型组)、模型组(用改良Zea Longa线栓法建立大鼠局灶性脑缺血再灌注损伤模型)、治疗组(建模前10 min从股静脉缓慢注射人工合成E-选择素10 mg·kg-1)。每组分为3、6、24、48和72 h 5个时间点(每个时间点大鼠n=12),应用多功能酶标仪测量血脑屏障对伊文思蓝(EB)的通透性,应用免疫组化法和Western blot法测定咬合蛋白及闭锁小带蛋白-1的表达含量。结果与假手术组比较,模型组缺血再灌注损伤后3 h脑组织EB含量开始上升,6 h继续上升,24 h达峰值,48~72 h下降但仍高于初始值;治疗组各时间点EB含量均低于模型组,两组比较差异有统计学意义(P0.05)。模型组咬合蛋白和闭锁小带蛋白-1的表达都于缺血再灌注3 h开始下降,6 h继续下降,24 h达最低值,48~72 h上升但低于初始值;治疗组各时间点咬合蛋白和闭锁小带蛋白-1的表达含量均高于模型组,两组比较差异有统计学意义(P0.05)。结论人工合成E-选择素可减轻大鼠脑缺血再灌注损伤造成的血脑屏障破坏,其机制可能与抑制紧密连接咬合蛋白和闭锁小带蛋白-1表达的减少有关。

Effect of Artificial Synthetic E-Selectin on Blood-Brain Barrier after Cerebral Ischemia Reperfusion Injury in Rats

Aim To study the effect of artificial synthetic E-selectin on blood-brain barrier（BBB） permeability and expression of tight junction proteins（occludin, ZO-1） after cerebral ischemia reperfusion injury in rats. Methods 180 male SD rats were randomly divided into sham-operation group, ischemiareperfusion group and artificial synthesized E-selectin treated group, 60 rats in each group. Each group was divided into 5 time points（3 h, 6 h, 24 h, 48 h, 72 h）, with 12 rats in each time points. The middle cerebralartery occlusion（MCAO） referring Longa＇s method and added some refinements was used to establish the focal cerebral ischemia model. Content of Evan＇s Blue（EB） was determined by enzyme-labeled instrument. The expression of occludin and ZO-1 was assayed by using immunohistochemical staining Western blot. Results The EB content of ischemia-reperfusion group began to increase at 3 h, and continue to rise at 6 h, reached the peak at 24 h, and began to decrease from 48 h to 72 h, and still was above the initial content. The EB content of artificial synthesized E-selectin treated group was significantly lower than that of the ischemia-reperfusion group at different time points of reperfusion（P〈0.05）; The expression of occludin and ZO-1 of ischemia-reperfusion group began to decrease at 3 h, and continue to reduce at 6 h, reached the lowest at 24 h and began to increase from 48 h to 72 h, and still was lower than that of the sham-operation group at 72 h. The expression of occludin and ZO-1 of artificial synthesized E-selectin treated group had the similar variation tendency of the ischemia-reperfusion group, but the expression levels was higher than that of the ischemia-reperfusion group（P〈0.05）. Conclusion The artificial synthetic E-selectin can alleviate the damage of blood-brain barrier caused by cerebral ischemia reperfusion in rats, which may be related to the up-regulation of occludin and ZO-1 expression.