Effects of Physical Training on the Myocardium of Oxariectomized LDLr Knockout Mice: MMP 2/9, Collagen I/III, Inflammation and Oxidative Stress. BACKGROUND:  The emergence of coronary heart disease is increased with menopause, physical inactivity and with dyslipidemia. Physical training is known to promote the improvement of cardiovascular functions. OBJECTIVE:  To investigate the effects of aerobic physical training on the left ventricle in ovariectomized LDL knockout mice. METHODS:  Thirty animals were divided into 6 groups (n = 5): Sedentary non-ovariectomized control; Sedentary ovariectomized control; Trained ovariectomized control; Sedentary non-ovariectomized LDL-knockout, sedentary ovariectomized LDL-knockout and trained ovariectomized LDL-knockout. We analyzed the average parameters of apparent density of collagen fibers types I and III, and metalloproteinase type 2 and type 9, were considered significant p < 0.05. RESULTS:  The results showed that the proposed exercise protocol altered the volume of type I collagen fibers, altered collagen remodeling parameters (MMP-2), and also reduced the 8-hydroxy-2''-deoxyguanosine (8OHdG) oxidative stress parameter. CONCLUSION:  Moderate intensity aerobic training acts on collagen fiber volume, on collagen remodeling with the reduction of oxidative stress in the left ventricles of ovariectomized LDL-knockout mice.