An experimental study on the effect of extract of leave ginkgo biloba(EGb24/6)on protection of the neurons and the observation of ultra-structure following nerve injury of sciatic nerve in rats

Objective To study the effect of extract of leave ginkgo biloba (EGb) for protection of the motor and sensory neurons axotomy-induced in rats. Methods Thirty male Sprague-Dawley rats weighing 180－ 220 g (8－ 9 weeks of age), were randomly divided into control group and EGb24/6 group. Models of sciatic nerve injury were established by transection of left sciatic nerve at 0.5 cm away from the points of muscular innervation. The proximal stump of sciatic nerve was double ligated to inhibit nerve regeneration. The distal end of the nerve was implanted into the biceps femoris. Then 2 ml of normal saline was given to control group, and 2 ml of EGb24/6 to the EGb24/6 groups daily. The rats were sacrificed in 7,14,28 days after surgery respectively, and then 4％ paraformaladehyde was perfused transcardially. The L4－ 6 spinal cord and L5 dorsal root ganglion (DRG) were harvested. HE staining and CV technique were used for detection of the motor neurons and compared with contra-lateral side. TUNEL technique was used for detection of apoptotic motor and sensory neurons. Eletron microscopic technique was used for observation of change of L5 DRG neurons. Result The number of motor neurons was significantly higher in EGb24/6 group in each postoperative period than that in control group (P 0.01). The number of apoptotic neurons (motor and sensory) were significantly less in EGb24/6 in all postoperative periods than that in control group(P 0.05). A series of changes happened with the lapse of time in the control group. The size of the nucleus decreased and nucleoplasm was scattered. The nucleolus was pale. Edema, loss of crest and matrix were found in the mitochondria. Satellite cells detached from the neuron cell body. The ultrastructure of L5 DRG sensory neurons in EGb24/6 group changed nearly normal following nerve injury. Conclusion This study demonstrated that EGb seemed to be possible to protect neurons and decrease the neuronal apoptosis.