Effects Of Ginkgo Biloba And Tongxinluo On NO Concentration In Rat Hippocampus With Transient Cerebral Ischemia And Reperfusion

Objective:To compare the effects of Ginkgo Biloba extract and Tongxinluo ultramicro-pulverization on nitric oxide(NO)concentration in SD rat hippocampus with transient cerebral ischemia and reperfusion and explore the mechanisms.Methods:32 adult male SD rats were randomly divided into four groups in this experiment,and 22 rats survived until the end of experiment:Saline group(n=8),7-Nitroindazole group(n=4),Ginkgo Biloba extract group(n=5)and Tongxinluo ultramicro-pulverization group(n=5).The model of cerebral ischemia and reperfusion was made by 4-vessel occlusion for 10min.In the first day of the experiment,all SD rats were anesthetized by intraperitoneal injection with phenobarbital(40mg·kg-1),and which both vertebral artery revealed surgery was occluded by electric cauterization permanently.In the second day of experiment,these SD rats were fixed on the operation table in supine position under urethane anaesthesia with 20%urethane(1.2g·kg-1)and taked a length of about 1.5cm neck incision,then both sides of the rats' carotid artery were loosely embosomed by medical silk suture.The both sides of the silk suture were hanged by 5g weigh and moved after 10 minutes.Loosen the wire on both sides and maintain perfusion within 60 minutes,to establish rat forebrain ischemia-reperfusion model.Each group was intraperitoneal injected with corresponding drugs in 20 minutes before building model.In the experiment,we measured arterial blood pressure,hippocampal blood flow and NO concentration by connecting the right femoral artery and ambulatory blood sedimentationunit,positioning the probe of the laser Doppler flowmetry into the left hippocampalregion,and positioning an NO-selective electrode on the right hippocampus of SD rats.Results:Before model building,the difference of mean arterial blood pressure(MABP),blood flow in the hippocampus and related physiological indicators in four groups(Saline group,7-NI group,Ginkgo Biloba extract group,Tongxinluo ultramicro-pulverization group)was not statistically significant(p>0.05)Similarly,the comparisons above-mentioned of four groups within group and among groups before the experiment,during cerebral ischemia and after ischemia-reperfusion were not statistically significant(p>0.05).10 minutes after ischemia-reperfusion,expression of NO in the hippocampus reached a peak:Saline group(2218.75±243.64)pA,7-NI group(900±98.43)pA,Ginkgo Biloba extract group(730±106.18)pA,Tongxinluo ultramicro-pulverization group(870±127.33)pA.Compared with the saline group respectively,the difference of NO expression in 7-NI group,Ginkgo Biloba extract group and Tongxinluo ultramicro-pulverization group was statistically significant(p<0.001).The difference between 7-NI group and Tongxinluo ultramicro-pulverization group was not statistically significant(p>0.05);But when compared with the Ginkgo Biloba extract group,which has stronger inhibition of NO synthesis during early ischemia-reperfusion,the difference was statistically significant(p<0.05).Conclusion:Ginkgo Biloba extract,Tongxinluo ultramicro-pulverization and 7-Nitroindazole all reduce the content of NO in hippocampus of rat.The effect of Ginkgo biloba compared with Tongxinluo is more noticeable.It is probably protective effect on hippocampal neurons against cerebral ischemia reperfusion injury,and it provides a new clinical neuroprotective care method.