The Neuroprotective Effects Of Ginsenoside Rd Against Spinal Cord Ischemic-reperfusion Injury

Objective: To investigate whether ginsenoside Rd has neuroprotective effect on glutamate-induced spinal cord motoneurons in vitro.Methods: The cultured spinal cord motoneurons were randomly assigned into four groups as follows. Control: no treatment; Glu: glutamate 300μM was added to the spinal cord neurons; GSRd+ Glu: the spinal cord neurons was pretreated with 10μM ginsenoside Rd for 30min, and then glutamate 300μM was added to the spinal cord neurons; Vehicle +Glu: the spinal cord neurons was pretreated with propylene glycol at the same volume as that used for ginsenoside Rd, and then glutamate 300μM was added to the spinal cord neurons. After the cultures were incubated with glutamate for 24h, the motor neurons were counted under phase-contrast microscopy; the neurons viability was determined by methylthiazoleterazolium(MTT)assay; the activity of lactate dehydrogenase (LDH) leaked into the culture medium also was meatured. Results: Compared to Glu group, the neuron count and neuron viability in GSRd+Glu group were significant higher(P <0.05); and the activity of LDH were significant lower(P <0.05). However, compared to Glu group , the neuron count,neuron viability and the activity of LDH in Vehicle + Glu group were no statistical differences.Conclusion: Ginsenoside Rd has neuroprotective effect on glutamate-induced spinal cord motoneurons in vitro.Experiment 2The neuroprotective effects of Ginsenoside Rd injection against spinal cord ischemic-reperfusion injury in rabbitsObjective: To investigate the effect of Ginsenoside Rd on the neural function and the histopathological changes after ischemic spinal cord injury in rabbits. Methods: Thirty-two male New Zealand white rabbits were randomly divided into for groups as follows : control group ( n = 8) receiving no pharmacologic intervention ;sham group ( n = 8) undergoing only the surgical exposure of the abdominal aorta; GSRd group (n=8) received intravenous infusion of 20mg/kg and ginsenoside Rd within 1h before aortic occlusion. Vehicle group(n=8) receiving intravenous infusion of the same volume of propylene glycol as ginsenoside Rd within 1h, Temporary spinal cord ischemia was induced by infrarenal aortic occlusion for 20 minutes and followed by reperfusion. The neural status was scored with the Tarlov criteria at 4, 8, 12 , 24 and 48 hours after reperfusion. All the animals were killed at 48 hours after reperfusion and the spinal cords ( L5 ) were removed immediately for histopathological study.Results : All animals survived in the experiment. The neurological function score and the number of normal neurons of anterior spinal cord of group after 48h reperfusion of group GSRd and group Sham were significantly higher than those of group Control and group Vehicle. (P <0.05) There was a strong correlation between the neurological function scores and the number of normal neurons of anterior spinal cord. (r=0.769. P <0.01)Conclusions : Ginsenoside Rd can significantly ameliorate the neural function and the histopathological damages after transient spinal cord ischemia in rabbits.Experiment 3The dose-effect relationship of Ginsenoside Rd injection against spinal cord ischemic injury in rabbitObjective: To investigate the dose response effects of ginsenoside Rd injection on ischemic injury of spinal cord in rabbits.Methods: Forty male New Zealand white rabbits were anesthetized with pentobarbital sodium and spinal cord ischemia was induced for 20 min by infrarenal aortic occlusion. Animals were randomly allocated five groups (n = 8 each). Group Control received no pharmacologic intervention. In group Rd-5, Rd-10, Rd-20 and Rd-40 received intravenous infusion of 5mg/kg, 10mg/kg, 20mg/kg and 40mg/kg ginsenoside Rd within 1h before aortic occlusion respectively. Neurologic status was scored by using the Tarlov criteria at 4 h, 8 h, 12 h, 24 h, and 48 h after reperfusion. The number of intact motor neurons in the anterior segment of the cord (L5 level) was counted after hematoxylin-eosin staining.Results: All animals survived in the experiment. The neurological function score after 48h reperfusion of group Rd-20 and group Rd-40 were significantly higher than those of group Control. The number of normal neurons of anterior spinal cord of group Rd-10, group Rd-20 and group Rd-40 were more than those of group Control, and the number of normal neurons of anterior spinal cord of group Rd-20 and group Rd-40 were more than those in group Rd-5, no difference was found between group Rd-10 and group Rd-5. There was a strong correlation between the neurological function scores and the number of normal neurons of anterior spinal cord.Conclusion: Ginsenoside Rd injection can effectively reduce neurological injury induced by spinal cord ischemia and reperfusion in a dose-response manner with a certain range of dosage.