The function of the extracts of Ginkgo biloba on rats spinal cord injury and its mechanism

Objective:To observe whether the extracts of Ginkgo biloba(EGb) can enhance the functional and structural recovery of the injured spinal cord of rats and to study the mechanism of EGb on spinal cord injury.Method:120 SD rats were randomly divided into four groups:sham group(group A),control group(group B),methylprednisolone(MP) treated group(group C) and EGb treated group(group D),30 rats for each group.The modified Allen method was adopted to make the models of T9 spinal cord injury.For group B the spinal cord were only injured,but not injection.For group C,MP(30mg/kg) was injected immediately by intraperitoneal injection.In group D,EGb was delivered 17.5mg/kg/d through intraperitoneally.BBB score was recorded at 24h,3d,5d,7d,14d respectively.The rats were sacrificed at 24h,3d,5d,7d,14d postinjury(n=6) and T9 spinal cord specimen was obtained,then the change of spinal cord was observed by HE stain through light microscope and the expression levels of B-cell lymphoma/leukemia gene-2(Bcl-2) and Bcl-associated x protein(Bax) protein in spinal cord were detected by immunohistochemistry assay.Result:The BBB score in group B,C and D were significantly lower than that in group A at each time point(P0.01),the score of group C and D was significantly higher than that of group B(P0.05) at 7 and 14 day time points,but group C and D showed no statistically significant differernce(P0.05) at each time point.HE stain showed the spinal cord of group C and D has fewer necrosis and the vacuole area in spinal cord than that of group B,while the spinal cord was normal in group A,group D has fewer hemorrhage and swelling of nerve cells than that of group C.The number of Bcl-2 positive of motor neuron in group B,C and D were significantly higher compared with those in group A(P0.01),however,the numbers of group C and D was significantly higher than that of group B(P0.01) at each time point,group D was significantly higher than that of group C at 7 and 14 day time points(P0.05).The number of Bax positive of motor neuron in group B,C and D were significantly higher compared with those in group A(P0.01),however,the numbers of group C and D was significantly lower than that of group B(P0.01) at each time point,group D was significantly lower than that of group C at 7 and 14 day time points(P0.01).Conclusion:EGb can inhibit abnormal expression of Bax protein,and increase the expression of Bcl-2 protein as to inhibit apoptosis of neuron after spinal cord injury.The efficacy of EGb was proved by the recovery of functional locomotion and the protection of the injured spinal cord,EGb appear that can inhibit secondary lesion one week after injury.