Effect Of BuYangHuanWu Recipe On The Cerebral Microcirculation In MCAO Rat After Reperfusion

Microcirculation dysfunction,which is induced by leukocytes and fibrin microthromboemboli plugging,and palatelets aggregation,initiates neuron damage after reperfusion. After reperfusion,microcirculation blood flow is decreased and the permeability of the microvasculature is elevated.Nowadays many methods are used to promote microcirculation function,but the effect on patients is lowered compared with on animal model.Although matrix metalloproteinase-9(MMP-9) is the most outstanding factor destroying the microvasculature and the blood-brain-barrier(BBB),there is little study about its gene and protein expression pattern after reperfusion in cerebral ischemia and there is few treatment inhibiting MMP-9 expression.Traditional chinese medicine play a very important role in treating cerebral ischemia.Those urge us to undertake this experiment.Methods A rat Zea-Longa MCAO model was used.Animals were falled into four groups: sham contol,model control and nimodipine group and BuYangHuanWu recipe group. Nimodipine group was given nimodipine(1.5mg/kg) ip.at the right time of MCA occlusion and reperfusion. BuYangHuanWu recipe group was given BYHWT(16g/kg) ip.at the right time of MCA occlusion and reperfusion.Sham contol and model control was given the same volume NS ip. at the right time of MCA occlusion and reperfusion.We measured cerebral infarct volume using TTC,neurological deficit score using Zausinger's method,the pial microcirculation blood flow using a closed window,BBB permeability using evan's blue(EB) dye,MMP-9 gene expression using RT-PCR and MMP-9 protein expression using zymography.Results Compared with the model control,the infarct volume 48 hour after reperfusion in BuYangHuanWu recipe group was significantly decreased and the neurological deficit score 24 hour after reperfusion was greatly promoted(P<0.05 or 0.01).In the model control the microcirculation blood flow displayed acute hyperemia and delayed post-ischemic hypoperfusion after reperfusion,which were inhibited by BuYangHuanWu recipe.BBB permeability after reperfusion displayed a two-phase open pattern,EB content in ischemic tissue reaching climax at 3 hour and 48 hour after reperfusion in the model control.BuYangHuanWu recipe could decrease the EB content(P<0.05 or 0.01).Under microscopy,the BBB in the sham control was as follows:the two neighbouring vascular endothelial cells(VEC) being closely connected by the tight junction,fewer vesicles in the vascular endothelial cell,the basal membrane being smooth.In the model control,there were many vesicles in the VEC 3 hour after reperfusion,and BBB was damaged 48 hour after reperfusion. BuYangHuanWu recipe could attenuated those damage .In the model control,MMP-9 mRNA began to express 24 hour after reperfusion,climaxed at 48 hour and declined at 120h.BuYangHuanWu recipe could lower the MMP-9 mRNA content(P<0.05).In the model control MMP-9 active protein could be measured at 24 hour,48 hour after reperfusion.MMP-9 pro-protein could also be measured at 48h after reperfusion(0.785(0.246) in the model control.In the BuYangHuanWu recipe group,MMP-9 active protein content was significantly decreased compared with model control(P<0.01).The correlation analysis showed that 48 hour after reperfusion the MMP-9 lysis was linly connected with EB content in the ischemic brain(r=0.922,P<0.05),which indicating MMP-9 plays a important part in the 48 hour'BBB open.Conclusions BuYangHuanWu recipe can modulate the cerebral microcirculation blood flow in MCAO rat after reperfusion and could protect the BBB which is in part through inhibiting the MMP-9 gene and protein expression.