Effect of ginkgo biloba extract on neuron apoptosis after acute spinal cord injury in a rat model

Objective To observe the effect of ginkgo biloba extract (EGb761) on neuron apoptosis and motor functional recovery after spinal cord injury(SCI) and the possible underlying mechanisms.Methods Sixty SD female rats were randomly divided into 3 equal groups (n =20):sham-operation,Allen impact SCI and EGb761-treatmrnt.Egb761-treated group received intraperitoneal injection of 100 mg/kg EGb761 per day; the other 2 groups were given normal saline of the same amount at the same time.After Basso Beattie Bresnahan (BBB) assessment and footprint analysis of the hind limb were performed on days 1,3,7 and 14 post-injury in each group,the animals were sacrificed to extract the spinal cord for HE staining.Apoptosis of nerve cells was observed by immunohistochemistry using TdT-mediated dUTP nick end labeling (TUNEL) and 3,3 '-diaminobenzidine tetrahydrochloride(DAB).Results In the sham-operation group,no influence on the BBB scores or footprint analysis of the hind limb was observed.There was no significant difference in ethology assessments on days l,3 and 7 between the SCI and EGb761 groups,but on the 14th day after surgery,the BBB score was significantly higher,the step length was significantly longer,and the step width was significantly smaller in the EGb761 group than in the SCI group (P ＜ 0.05).On days 1,3,7 and 14,there were significantly more TUNEL-positive and Caspase-3 protein-positive cells in the SCI and EGb761 groups than in the sham-operation group (P ＜ 0.05) ; on days 3 and 7 after surgery,the TUNEL-positive and Caspase-3 protein-positive cells in the EGb761 group were significantly fewer than in the SCI group (P ＜0.05).Conclusions EGb761 has a positive protective effect on nervous injury after SCI.This protective effect may be realized by down-regulating the expression of Caspase-3 protein,inhibiting cellula nervosa (especially glial cells) apoptosis at injured and surrounding portions in the myeloid tissue. Key words: Spinal cord injury;  Apoptosis;  Ginkgo biloba extract