Effect Of Ginsenoside On Mitochondrial Function In Cardiac Arrest Rats And Evaluation Of The Experimental Model

Objective Part 1:To compare the characters of three commonly used rat models of cardiac arrest (CA) which were induced by electric stimulation, KC1 and asphyxia respectively. Their influence on organismal environment and energy metabolism was also studied. Part 2:To investigate the effect of Ginsenoside on structural and functional changes of mitochondrion as well as survival rate and energy metabolism of the organism after Return of Spontaneous Circulation (ROSC) in the rat model of Electric Stimulation induced CA.Methods Part 1:102 male Wstera rats were randomly devided into 3 groups:1) Electric Stimulation group (n=36):CA was induced by alternating current via pacing electrode placed in esophagus.2) KC1 group (n=44):CA was induced by KC1 injected intravenously.3) Asphyxia group (n=22):CA was induced by clamping the tracheal tube. Each of the upper groups was devided into 2 subgroups respectively according to the intervention time -- 1) 5min after CA but no resuscitation (CA5),2) right after ROSC (R0). After 5-min-interval of CA, chest compression (about 200/min) was begun together with epinephrine (100μg/kg) and artificial ventilation in the R0 subgroup. For each model, the CA incidence (CAI), the electrocardiographic manifestation of CA and the ROSC ratio were recorded. The vital sign, blood gas, serum electrolyte, Glucose and Lactic Acid (LA) value were measured. Meanwheal, the AMP, ADP and ATP content of myocardium were detected by high-performance liquid chromatography (HPLC), and then energy charge (EC) was calculated. Part 2:Another 870 male Wstera rats were randomly devided into 5 groups according to the drugs administered during cardiopulmonary resuscitation (CPR):1) epinephrine (E) group (n=450), epinephrine(100μg/kg) was injected; 2) anisodamine (A) group (n=110), anisodamine (10mg/kg) and epinephrine(100μg/kg) was injected; 3) ginsenoside (G) group (n=160), ginsenoside rgl (20mg/kg) and epinephrine(100μg/kg) was injected; 4) combination (C) group (n=110), ginsenoside rgl (20mg/kg) and anisodamine (10mg/kg) and epinephrine (100μg/kg) was injected; 5) Sham group (n=40). All animals in the fomer 4 groups got CA induced by electric stimulation and experienced CPR operation as described in Part 1. Those in Sham group were performed sham operation. Animals in each of the upper groups were devided into 5 subgroups respectively according to the survival time after ROSC (Oh,3h,6h,12h and 24h subgroup). For each group, the ROSC ratio and survival time were recorded, the EC of myocardium was detected. Heart mitochondria were harvested to measure the Membrane Potential (MP) and Reactive Oxygen Species (ROS) by Laser Scanning Confocal Fluorescence Microscope and Fluorescence Microplate Reader. Morphology changes of heart tissue was observed through electronmicroscope.Results Part 1:The Asphyxia group had a higher CAI, ROSC ratio, LA level and PCO2, whereas a lower EC level compared with the other two groups (p<0.05). The KC1 group had a higher EC and potassium level, whereas a lower CAI (p<0.05). Both Electric Stimulation and KC1 group can induce multiple arrhythmia, predominantly ventricular fibrillation and ventricular tachycardia. However, Asphyxia group can just induce pulseless electrical activity or electrical asystole. Part 2:G, A and C group had a higher survival ratio compared with E group (p<0.05), but there were no significant defference among the former 3 groups (p>0.05). As for EC, MP and ROS, the main effect of ginsenoside and anisodamine and their interaction were all significant (p<0.05). ROS level in C group was lower than G and A group. the EC of G3h subgroup was higher than A3h subgroup, whereas the MP of G0h-G6h subgroups were lower than A0h-A6h subgroupos respectively (p<0.05). Electronmicroscope showed the impaired mitochondrion recovered 3 hours after ROSC with functional enhancement appearance.Conclusion 1. Electric Stimulation method can induce a condition of CA similar to Clinical pathophysiology with slight influence on organismal environment. Its CAI and influence on EC were intermediate between KC1 and Asphyxia group. So the method was more suitable for our experiment. 2. Ginsenoside rgl can improve the survial and energy metabolism of the asystole rats after ROSC, which attributed to its promoting functional compensation of nomal mitochondria and improving the structure and function of the impired mitochondria. 3. Ginsenoside didn't increase the ROSC ritio. 4. Combinated with anisodamine help to decrease the production of ROS.