Effect Of Acute Myocardial Inflammation Reaction Motion Dynamic Changes Of Myocardial Mitochondria

Objective: Using SD rat as exercise training model, we compared mitochondrialfunction and the expression of mitochondrial fusion and fission protein between acuteexercise period and recovery period. The relationship between mitochondrial dynamicchange and inflammation-related proteins were also analyzed.Methods:48Male Sprague–Dawley (SD) rats were randomly divided into eightgroups (6rats per group): control group (C), exercise training45min (E45),90min(E90),120min group(E120), post-exercise recovery12h (R12),24h （R24）,36h（R36）,48h（R48). Rats were subjected to an acute bout of treadmill running atvarious durations and killed immediately or during recovery. State3and state4respiration rates, reactive oxygen species (ROS) generation, trans-innermembranepotential and ATP synthase activity were measured in isolated myocardialmitochondria. The protein expression of myocardial Mfn1/2，OPA1，Drp1，Fis1，IL-1βand NLRP3were determined via western blotting.Result：1. Myocardial mitochondrial respiratory function and ROS generation rate:1) Compared with group C, mitochondrial membrane potential showedprogressive increases in E45group but progressive dropped in E120group.2) Compared with group C, mitochondrial ATP synthase activity wassignificantly higher in both E45group and R24group. In E120group, the enzymeactivity decreased.3) Compared with group C, in E45group, mitochondrial state3, state4respiration rate and mitochondrial respiratory control ratio (RCR) were increasedsignificantly. In E120group, state3respiration rate was significantly lower, state4was significantly higher, and RCR was significantly lower. In R24group,mitochondrial state3respiration was significantly higher, and RCR wassignificantly higher. The rest of the group returned to the normal level. 4) Compared with group C, along with the training time, mitochondrial ROSgeneration rate gradually increased. Even in12hours recovery, the ROS level is stillhigher than control. The ROS level returned to the normal levels at24hours recovery.2the expression of mitochondrial dynamics related proteins:1) Compared with group C, along with the exercise time, Mfn1proteinexpression gradually decreased and the lowest point appeared at E120. Mfn1expression level of R12group is still lower than that of control group. After24hoursrecovery, there is no significant difference between control group and experimentalgroups. Mfn2showed similar trends with Mfn1during training, but its level rosesuddenly in early recovery (less then24hours). From36hours recovery Mfn2levelreturned to the normal levels. For OPA1, the expression level only showedsignificantly lower at E120group and R12group.2) Compared with group C, along with the exercise time, Drp1proteinexpression was significantly higher. Fis1protein expression was significantly higherand continued to36hours recovery, The Fis1protein level returned to the normallevels at48hours recovery.3inflammatory response related proteins:Compared with group C, NLRP3protein expression showed progressiveincreases in R12group and R24group. In E45group, R12group and R24groupIL-1β protein expression increased significantly, and IL-1β level returned to thenormal level at36hours recovery.Conclusion1）In the early period of acute bout of treadmill running exercises, myocardialmitochondrial oxidative phosphorylation function enhanced, in late stage declined,and in the recovery period gradually rise back to the normal levels.2） In an acute exercise and in the early of recovery period myocardialmitochondrial ROS generation rate increased, and gradually returned to normal levels. 3）In an acute bout of treadmill running exercises myocardial mitochondrialdynamics trend to fission and in the recovery period gradually transformed to fuse.4) After acute exercise myocardial inflammation factor NLRP3, IL-1β proteinexpression was significantly increased.5）In an acute exercise and the recovery period the changes of mitochondrialdynamics may affect myocardial inflammation.