白蛋白对老年大鼠全脑缺血再灌注后G蛋白偶联受体124表达和血脑屏障的影响

Effects of albumin on the expression of G-protein coupled receptor 124 and blood-brain barrier after global cerebral ischemia-reperfusion in elderly rats

目的研究人血白蛋白(HSA)对老年大鼠全脑缺血/再灌注后血脑屏障通透性和G蛋白偶联受体124(GPR124)表达的影响。方法选用老年健康雄性Wistar大鼠共108只,按随机法分成3组:假手术组(Sham)、全脑缺血再灌注模型组(GCI/R)和人血白蛋白治疗组(GCI/R+HSA),每组36只。应用改良Pulsinelli四血管阻断法(4-VO)构建全脑缺血再灌注大鼠模型(GCI/R),短暂缺血15 min后再灌注。再灌注2 h后,经颈外静脉注射2.5 g/kg的HSA。再灌注后6、24、48 h,用伊文思蓝(EB)定性法分别检测血脑屏障的通透性。采用Western Blot(WB)、实时荧光定量PCR(qRT-PCR)和免疫荧光分析(IF)方法检测GPR124表达的变化。结果脑组织中的伊文思蓝(EB)在再灌注后开始增加,这种增加趋势可以通过HSA的干预来减轻。免疫荧光分析(IF)显示,GCI/R组GPR124的平均荧光强度在全脑缺血再灌注后24 h显著高于Sham组(P<0.01);与GCI/R组相比,GCI/R+HSA组GPR124的平均荧光强度进一步增加,表明GPR124表达增加,具有显著性差异(P<0.05)。WB和qRT-PCR检测到的GPR124蛋白和mRNA的表达趋势与IF结果基本一致。结论HSA能减轻大鼠全脑缺血/再灌注损伤和血脑屏障的破坏,促进GPR124在脑组织中的表达。GPR124可能在HSA的脑保护机制中发挥重要作用。

Objective To investigate the effects of human serum albumin(HSA)on the permeability of blood-brain barrier(BBB)and the expression of G-protein coupled receptor 124(GPR124)after global cerebral ischemia/reperfusion(GCI/R)in elderly rats.Methods 108 elderly male Wistar rats were randomly divided into 3 groups:sham operation group,global cerebral ischemia/reperfusion(GCI/R)group and HSA treatment(GCI/R+HSA)group,with 36 ones in each group.The modified Pusinelli four-vessel occlusion method(4-VO)was used to establish a rat model of global cerebral ischemia/reperfusion(GCI/R),which was reperfusion after transient ischemia for 15 min.Two hours after reperfusion,2.5 g/kg HSA was injected through external jugular vein.The permeability of BBB was detected by Evans Blue(EB)qualitative method at 6,24,48 h after reperfusion,respectively.Western blot(WB),quantitative real-time PCR(qRT-PCR)and immunofluorescence(IF)analysis were used to detect the changes of GPR124 expression.Results EB in brain tissue began to increase after reperfusion,and this increasetrend can be diminished by the administration of HSA.IF assay demonstrated that the mean fluorescence intensity of GPR124 in the GCI/R group was significantly higher than that in the sham group 24 h after global cerebral ischemia reperfusion(P<0.01).Compared with GCI/R group,the mean fluorescence intensity of GPR124 in the GCI/R+HSA group was further increased,indicating that the expression of GPR124 was increased(P<0.05).The expression trends of GPR124 proteins and mRNA detected by WB and qRT-PCR were basically consistent with the results of IF.Conclusion HSA can alleviate the global cerebral ischemia/reperfusion injury and the damage of BBB in rats,and promote the expression of GPR124 in brain tissue.GPR124 may play an important role in the brain protection mechanism of HSA.