The Protective Effect And Mechanism Of Cyclovirobuxine-D On Cerebral Ischemic Reperfusion Injury In Hypertensive Rats

Objective:To study the effects of the CVB-D on the damage of cerebral ischemia and reperfusion in Stroke-prone-Renovascular-Hypertensive-Rats (RHRSP), and to investigate the possible mechanism of CVB-D on the regulation of the neural growth factors and inhibitory factors.Methods:RHRSP models were established by bilaterally narrowing the renal artery with silver loop clips. The models of middle cerebral artery occlusion (MCAO) rats were established by stringing middle cerebral artery occlusion in RHRSP. And then, both two models were randomly divided into blank group (n=10), sham-operation group (n=10), control group (n=40) and CVB-D treated group (n=40). After 2h ischemia and 1-day,7-day,14-day and 30-day reperfusion, CVB-D (6.48 mg/kg), dissolved in normal sodium (NS) 1.5 ml, was injected into abdominal cavity in CVB-D treated group twice daily. Meanwhile, the control group was given the injcection of only NS. After that, the cerebral water contents were measured by weighting method; the infarct size (IS) of cerebrum was assayed by microscopy and microcomputer image analysis system; the ethological grade was assessed by Zea Longa 5; the damage of cerebral cell ultrastructure was detected by transmission electron microscope; the expression of GAP-43mRNA was detected by hybridization in situ; the productions of neurocan, GFAP, SYN, GAP-43 were detected by immunohistochemistry in both CVB-D treated group and control group.Results:①Respectively, the cerebral water contents and IS in CVB-D group after 7-day,14-day and 30-day cerebral ischemia and reperfusion were 80.14±1.33%/21.57±2.18%,79.22±1.28%/17.84±2.23 %,77.43±1.42%/15.32±2.04% and 76.75±1.18%/11.41±2.17%, which were significantly lower than control group (P<0.05 or P<0.01). While the ethological grade, blood pressure and death roll had no significant differences between two groups (P>0.05).②The damage of cerebral ultramicrostructure in CVB-D group was less serious than in the control group.③The expression of GAP-43mRNA was detected in the ischemic area and the parahippocampal area. It increased significantly after 2h reperfusion and was up to the maximum after 7-day reperfusion, decreased after 14-day reperfusion and reduced markedly after 30-day reperfusion. The expression of GAP-43mRNA in CVB-D group was obviously higher than that in the control group (P<0.05).④The expression of SYN and GAP-43 in CVB-D group after 1-day,7-day, 14-day and 30-day cerebral ischemia and reperfusion were increased. The GAP-43mRNA positive cells in CVB-D treated group were more than that in control group. After 1-day cerebral ischemia and reperfusion, the positive GFAP and neurocan cells had no significantly differences between CVB-D treated group and control group. But after 7-day,14-day and 30-day cerebral ischemia and reperfusion, they were much less in CVB-D treated group than in control group.Conclusion:The neural growth factor and inhibitory factor play an important role in the recovery process of central nerve system after cerebral ischemic and reperfusion damage. CVB-D can lighten the damage of cerebral ischemia and reperfusion by reducing the cerebral water contents and diminishing the cerebral infarct size. The mechanism of CVB-D is related with the up-regulation of SYN, GAP-43 and GAP-43mRNA expression and the down-regulation of GFAP and neurocan expression, which is resulted to promote the regeneration of nerve and functional reconstruction.