[Salvianolic acid B alleviate the disruption of blood-brain barrier in rats after cerebral ischemia-reperfusion by inhibiting MAPK pathway].

The aim of the study is to investigate the effect of salvianolic acid B(SalB) on blood-brain barrier(BBB) in rats after cerebral ischemia-reperfusion,and to illustrate its possible mechanisms.Cerebral ischemia-reperfusion was induced by middle cerebral artery occlusion in rats.The break-down of BBB was indicated by extravasations of immunoglobulin(IgG) monitored with immunohistochemistry.The expression of MMP-9 and NOS2 in the brain was determined by immunohistochemistry,and the expression of p-p38 and p-ERK1/2 was detected by Western blotting.It was shown that on day 2 after ischemia-reperfusion the IgG accumulated around the vascular boundary zone,suggesting the break-down of BBB,and the expression of MMP-9 and NOS2 up-regulated at the same time.The result of Western blotting suggested that the expression of p-p38 and p-ERK1/2 increased.On day 7 after ischemia-reperfusion the expression of MMP-9 and NOS2 was about the same level as day 2,the expression of p-p38 was higher than that on day 2 and the expression of p-ERK1/2 was slightly lower than that on day 2.SalB(1 and 10 mg.kg?1) significantly alleviated the extravasations of immunoglobulin induced by cerebral ischemia-reperfusion(P 0.05).On day 2 and day 7 SalB attenuated the expression of MMP-9 and NOS2(P 0.05).SalB(10 mg.kg?1) reduced the expression of p-p38 and p-ERK1/2 apparently on day 2 and 7 after ischemia-reperfusion(P 0.05).SalB(1 mg.kg?1) inhibited the expression of p-p38 on day 7 after ischemia-reperfusion(P 0.05).The results indicate that SalB protects blood-brain barrier in rats after cerebral ischemia-reperfusion by inhibiting the MAPK pathway.