Study on Heavy Load Training-induced Cardiac Contractility Changes of Rats,and the Relationship between this Changes and the Levels of Cardiac Free Radical,Calcium Ions

The purpose of this study was to obtain the information about cardiac contractility dynamical changes after once heavy load training on treadmill, summarized its variation characteristics and explored the relationship between this change and the levels of cardiac free radical, calcium ions.32 grown male SD rats, randomly divides into normal control group (group A) , instantly after exercise group (group B) , and 3h after exercise group (group C) , and 24h after exercise group (group D) .The cardiac contractility signal of group D was used to monitor before exercise and different time after exercise by exercise cardiac contractility monitor.The levels of all groups rats serum cardiac troponin-I (cTnI) , cardiac superoxide dismutase (SOD, malondialdehyde (MDA) and Ca2+ were determined.The result showed that first heard sound (S1) amplitude of rats was lower in instantly after exercise, and was further and significant lower in much time follow instantly after exercise, but the amplitude of S1 returned to normal levels at 24 hours after exercise.Exercise caused serum cTnI concentration was significant lower, and caused cardiac SOD activity was significant lower, cardiac MDA quantitative was significant higher and Ca2+ concentration was significant higher.These changes were the most obvious of group C.It is concluded that heavy load training may lead rats cardiac contractility to drop, and the most obvious changes occurred convalescence after exercise, but it was reversible.It also hints that there might be some certain relationship between lowing of cardiac contractility and free radical increase, calcium overload.