Effect Of Exogenous CoQ On Activities Of Respiratory Chain Complexes In Mitochondria From Mice's Liver

CoQ acts as an electron carrier in the respiratory chain in mitochondrial and could regulate physiological function of body.It could transport electrons from complexesⅠandⅡto complexⅢ,during which protons are extruded to the outer mitochondrial compartment thereby generating a transmembrane electrochemical gradient.It also plays an important role in ATP synthesizing.The update studies show that CoQ may be concerned with the limited speed during its transferring electrons in the mitochondrial electron transport chain.By means of perfusing CoQ into mice's stomach and exercise training,this experiment measured the activities of respiratory complexesⅠ,Ⅱ,ⅢandⅣin mitochondria isolated from liver of mice.The purpose of this study is to examine the effect of supplying CoQ and training on activities of respiratory complexes and try to find a way to improve mitochondrial function by nutrition supplement.Methods:36 male SD mice were randomly divided into 4 groups after a week's adaptive feeding.They are Control Group(NC),CoQ Supplementation Group(QC), Exercise-Training Group(NE)and Combining CoQ Supplementation with Exercise-Training Group(QE).The mice from NC and QC did no exercise at all while the mice from NE and QE were given 7 weeks' treadmill training(speed from 15m/min gradually increasing to 35m/min,20 to 30 min/d duration with the slope at 0 degree).The mice from QC and QE were perfused CoQ(2mg/100g·weight)between 6pm and 7pm each day while mice from NC and NE were peffused the same dose of distilled water.All the mice were killed by means of decollation after exhaustive running on the treadmill on Monday in the 8th week.Superoxide dismutase(SOD)and malondialdehyde(MDA)were measured in serum,and activities of respiratory complexesⅠ,Ⅱ,ⅢandⅣwere measured in mitochondria isolated from liver.Results:(1)After 7 weeks' feeding and training,QC comparing with NC,QE comparing with NE,the scope of mice's weight increasing represented no marked difference(P＞0.05).Compared with NC,the weight of mice from both NE and QE increased much less(P＜0.01).Compared with QC,the weight of mice from QE also showed a lower increasing scope(P＜0.001).(2)The time of mice running to exhaustion showed no significant difference between QC and NC,NE and QE(P＞0.05).NE comparing with NC,QE comparing with NC and QE comparing with QC,the time of mice from NE and QE running to exhaustion were much longer(P＜0.01).(3)Compared with NC,the activity of SOD in serum of mice from QC showed no distinct difference after exhaustive running(P＞0.05),but the amount of MDA in serum of mice from QC increased significantly(P＜0.05);the activity of SOD in serum of mice both from NE and QE increased remarkably(P＜0.001),and the amount of MDA in serum of mice both from NE and QE decreased remarkably(P＜0.01). Compared with QC,the activity of SOD in serum of mice from QE showed an obvious increase(P＜0.001),and the amount of MDA in serum of mice from QE showed an obvious decrease(P＜0.01).Compared with NE,the activity of SOD and the amount of MDA in serum of mice from QE both represent an increasing trend,but there was no marked difference(P＞0.05).(4)Compared with NC,the activity of CⅠin mitochondria from mice liver of QC revealed a significant rise(P＜0.05),but the activities of CⅡ,CⅢand CⅣchanged little(P＞0.05);Both the activities of CⅠand CⅡin mitochondria from mice liver of NE raised remarkably(P＜0.05),so did as the activity of CⅢand CⅣ(P＜0.001);The activities of respiratory chain complexesⅠ,Ⅱ,Ⅲand Ivin mitochondria from mice liver of QE ascended remarkably(P＜0.001).Compared with QC,The activities of respiratory chain complexesⅠ,Ⅱ,ⅢandⅣfrom mice liver mitochondria of QE revealed an obvious increase(P＜0.05,P＜0.001,P＜0.001,P＜0.01).Compared with NE, Both the activities of CⅠand CⅡin mitochondria from mice liver of QE raised significantly(P＜0.05),however,there was no marked differences in the activities of CⅢand CⅣ(P＞0.05).Conclusion:(1)There was no effect of CoQ supplementation on the increase of mice's weight,however,exercise-training could reduce the rate of mice's weight increasing.(2)There was no effect of CoQ supplementation on prolonging the time of mice running to exhaustion,but exercise-training could increase exhaustive time of mice running so as to improve their sports ability.(3)There was no effect of CoQ supplementation on activity of SOD in serum of mice,moreover it might result an ascending trend of MDA.(4)CoO supplementation to mice improved activities of respiratory chain complexesⅠandⅡin mitochondria from liver,and could make benign influence on complexesⅢandⅣ.This could accelerate the process of oxidative phosphorylation and help to synthesize ATP.However,supplying mice with CoO could not effectually postpone the time of occurrence of exercise-fatigue.