HBOC Attenuates Intense Exercise-Induced Cardiac Dysfunction

The purpose of this study was to investigate whether hemoglobin-based oxygen carrier (HBOC) could protect the heart from intense exercise-induced myocardial dysfunction. Adult male Sprague-Dawley rats were subjected to 5-h intense prolonged running on treadmill with or without HBOC pre-treatment. Immediately after exercise, the heart rate (HR) and oxygen delivery capacity of the blood were measured. After 1 h of rest, echocardiography was performed to assess the post-exercise cardiac function. Then all the hearts were isolated and perfused using the Langendorff model for 1 h. Our results proved that pronged exercise caused significant LV dysfunction, while HBOC pre-treatment attenuated such a damage, as evidenced by the increased oxygen delivery, cardiac fractional shortening (FS), rate-pressure product (RPP), ±dp/dt and coronary flow rate (CF) and decreased myocardial necrosis. The releases of cardiac enzymes, including creatine kinase-MB (CK-MB) and cardiac troponin-I (cTnI) were markedly reduced. No significant difference of cardiac infarct size was observed among groups. In addition, HBOC significantly elevated superoxide dismutase (SOD) activity and decreased hydrogen peroxide (H 2 O 2 ) formation, which indicated the exercise-induced cardiac oxidative damage was inhibited. In conclusion, HBOC pre-treatment showed a promising cardioprotective effect on prolonged exercise-induced cardiac dysfunction, which was probably associated with its ability to decrease myocardium oxidative stress.