Comparison of changes in markers of muscle damage induced by eccentric exercise and ischemia/reperfusion

To examine the effects of eccentric exercise (EE) and ischemia/reperfusion (I/R) on the markers of muscle damage, 72 rats were randomly assigned to the EE group, I/R group and control group (C), respectively. The rats in EE ran downhill on a treadmill with a 16 ° inclination at a constant speed for 90 min, and the rats in the I/R group underwent 90 min of four-limb ischemia, followed by 24, 48 and 72 h of reperfusion. Blood and tissue samples were collected immediately, 24, 48 and 72 h after exercise or reperfusion. Quantitative analyses showed that the I/R group had a significantly larger mitochondrial volume at 24 h after reperfusion compared with the C, and there were more disrupted Z-lines in the EE group and more disrupted mitochondria in the I/R group at 24 h after exercise or reperfusion. When compared with the C, a significantly lower total antioxidant capacity and higher interleukin-6 value were observed after exercise or reperfusion. Our data suggest that although EE and I/R result in some similar changes in the muscle damage markers, there are still some differences. The EE- and I/R-induced muscle damage may be due to different mechanisms.