Role of endogenous endothelins in heart injury in burnt rats

The purpose of this study was to investigate the role of endogenous endothelins in postburn heart injury by use of a 30% TBSA Ⅲ degree burnt rat model. Dynamic changes of endothelins in postburn rats were measured, and the effects of PD₁₄₅₀₆₅, a kind of non selective endothelin receptor antagonist, on heart injury in burnt rats were observed. The main results were as follows: Not only did the endothelin concentration in plasma of burnt rats elevate significantly, but also the endothelin contents in heart muscle apparently increased, which negatively correlated with the changes of water content in heart. Administration of endothelin receptor antagonist PD₁₄₅₀₆₅ had been morphologically and biochemically demonstrated to be able to prevent heart from damage to some extents, by means of stimulation of the activity of SOD or N⁺-K⁺ ATPase, enhancement of the contents of ATP and ADP, and reduction of the severity of edema in heart. These results suggest that endogenous endothelin may contribute to the postburn heart injury in the early stages in rats through vascular contraction and tissue hypoxia which in turn induces ATP depletion and lipoperoxidation damage.