Daily Oxygen/O3 Treatment Reduces Muscular Fatigue and Improves Cardiac Performance in Rats Subjected to Prolonged High Intensity Physical Exercise

Rats receiving daily intraperitoneal administration of O-2 and running on a treadmill covered an average distance of 482.8 +/- 21.8 m/week as calculated during 5-week observation. This distance was increased in rats receiving daily intraperitoneal administration of an oxygen/O-3 mixture at a dose of 100; 150; and 300 mu g/kg with the maximum increase being +34.5% at 300 mu g/kg and still present after stopping the administration of oxygen/O-3. Oxygen/O-3 decreased the mean arterial blood pressure (-13%), the heart rate (-6%), the gastrocnemius and cardiac hypertrophy, and fibrosis and reduced by 49% the left ventricular mass and relative wall thickness measurements. Systolic and diastolic functions were improved in exercised oxygen/O-3 rats compared to O-2 rats. Oxygen/O-3 treatment led to higher MPI index starting from the dose of 150 mu g/kg (p < 0.05) and more effective (+14%) at a dose of 300 mu g/kg oxygen/O-3. Oxygen/O-3 dose-dependently increased the expression of the antioxidant enzymes Mn-SOD and GPx1 and of eNOS compared to the exercised O-2 rats. The same doses resulted in decrease of LDH levels, CPK, TnI, and nitrotyrosine concentration in the heart and gastrocnemius tissues, arguing a beneficial effect of the ozone molecule against the fatigue induced by a prolonged high intensity exercise.