Effect of ginsenoside-Rd injection on central nervous system and cardiac toxicities of bupivacaine in rats

AIM: To study the effect of ginsenoside-Rd injection, a preparation of Chinese herbal medicine, on the central nervous system (CNS) and cardiac toxicities of bupivacaine in rats. METHODS: Thirty male Sprague Dawley rats weighing 280-320 g were randomly assigned to three groups: control group (C), ginsenoside-Rd group (R) and solvent group (S) (n=10 each). Animals in the R group received ginsenoside-Rd injection 30 mg/kg ip 30 min before iv infusion of bupivacaine, whereas rats in the C and S groups received an equal volume of saline injection or ginsenoside-Rd solvent (propylene glycol), respectively. Lead II of the electrocardiogram (ECG) was continuously monitored by three needles stuck into the skin of both forelimb extremities and the left hindleg. The femoral artery was cannulated for direct measurement of arterial blood pressure and for drawing blood samples and the femoral vein was cannulated for bupifacaine infusion. After the basic parameters (arterial blood pressure, heart rate and arterial blood gases) were recorded, 0.5% bupivacaine was infused iv at a rate of 2 mg/(kg·min) to both groups until asystole. The times for bupivacaine-produced convulsions, arrhythmia (QRS prolongation in ECG), circulation collapse (MAP≤40 mmHg) and asystole were determined and the cumulative dose of bupivacaine was calculated at the corresponding timepoints, respectively. RESULTS: MAP values were significantly increased and the HR was significantly decreased after bupivacaine infusion and the occurrence of convulsion and arrhythmia in both groups. No significant difference was seen in the MAP and HR at the corresponding timepoints between groups. When the MAP was 40 mmHg, the arterial PO2 in the Rd groups was remarkably higher than in the bupivacaine group (P<0.05). In the ginsenoside-Rd group, cumulative doses of bupivacaine that produced convulsion, arrhythmia and circulation collapse were (17.4±1.6), (18.1±5.2) and (30.0±5.0) mg/kg, respectively, significantly higher than the doses in the control group (13.8±1.3), (13.4±4.7) and (24.2±5.8) mg/kg. CONCLUSION: Pretreatment with ginsenoside-Rd injection reduces the toxicity of bupivacaine to the central nervous and cardiac systems in rats.