Effect Of Ginkgo Biloba Extract On Cerebral Vasospasm In Experimental Subarachnoid Hemorrhage In Rabbits

Objective: As the severe complication of subarachnoid hemorrhage(SAH), delayed cerebral vasospasm (DCVS) is responsible for the disability and mort- ality of patients with SAH However, it isn't understood about mechanism of DCVS development, which couldn't find satisfied treatment。The paper was designed to evaluate the effects of Ginkgo biloba Extract(EGb) on cerebral vasospasm and disturbance of microcirculation in experimental Subarachnoid hemorrhage(SAH)。Methods: A double-hemorrhage rabbit model of vasospasm was establ- ished by slow injection of 0.5m1/kg of fresh non-heparinized autologous arterial blood into the cisterna magna twice at 48-hour in-tervals. Thirty mature Japan-long-eared rabbits were divided randomly into 5 groups, A: Control group; B: Sham-operated group (0.5m1/kg of 37℃saline into cisterna magna),CSAH group, D:SAH+ Nimotop group, Nimotop 0.2mg/kg was admin- istered intravenously every day, E: SAH+EGb group, EGb 5mg/kg was admin- istered intravenously every 12 hours, all treatment began after the SAH 1 hour. The blood velocities of basilar artery were examined and recorded by Transcr- anial Doppler (TCD) before and after SAH induced. The rabbits were sacrificed on 5th day after SAH,at the same time by light microscopy, the changes of neurons in the piriform cortex and hippocampal CA1 and the morphology of basilar artery were observed.Results:1.The blood flow velocities of basilar artery examined with TCD in SAH group were higher than that in control and sham-operated group, and two treated groups (P<0.01),but there was no significant difference in Nimotop and EGb-treated groups (P>0.05).2. Morphometric examination showed a significant contraction of diamet- ers accompanied by a striking increase of wall thickness of basilar artery in SAH group. Treatment with Nimotop and EGb respectively,the diameters and the cross-sectional areas of basilar artery had obvious increase.3. In addition, histological examination at autopsy predominantly showed ischemic changes in the brain in SAH group. Animals in Nimotop and EGb-treated group exhibited ischemic changes less frequently than those in the non-treated group.Conclusions:The study indicated that EGb could make the spastic cerebral artery dilatation, exert a brain protective role against the detrimental effect of hemorrhage. It was inferred that the compound had a dual function of inhibiting Lipid peroxid action and antogonizing calcium. Of course, further studies were needed to testify the precise mechanism of functions of EGb on cerebral vasosp-...