The Role of Superoxide and Nitric Oxide in the Development of Myocardial Injury in Rat Myocarditis.

The mechanism of myocardial injury in myocarditis is still unclear. Recently, nitric oxide (NO), massively produced in the inflammation, has been suggested to be harmful for tissue at excess amount as well as superoxide. However, it is still unclear the relationship between production of NO with superoxide and myocardial damage in myocarditis. In this study, we investigated whether NO and/or superoxide play an important role in the pathogenesis of myocardial injury in myocarditis.The heart tissue specimens were taken from Lewis rats with experimentally induced myocarditis. Immunohistochemical staining was performed using polyclonal antibody for inducible NO synthase by avidin-biotin peroxidase complex method in paraffin sections of the tissue. Histochemical study for ultrastructural H2O2-producing site in the heart tissue was carried out by Brigg’ s method using CeCl3; briefly, the heart tissues were incubated in 0.1M Tris-malate buffer with ImM CeCl3 and 10mM aminotriazole. Then tissues were fixed in 2% glutaraldehyde, postfixed with 1% OsO4 and embedded in resin for electron microscopy.