Sulfur Dioxide: An Endogenous Protector Against Myocardial Injury

Abstract: Sulfur dioxide (SO 2 ) was previously known as a harmful gas in air pollution. Recently, it was reported that SO 2 can be endogenously generated in cardiovascular tissues. Many studies have revealed that endogenous SO 2 has important physiological and pathophysiological significance and pharmacological potential. As a novel gasotransmitter, SO 2 has important regulatory effects on the heart. It has a dose-dependent negative inotropic effect on cardiac function, in which L-type calcium channels are involved. SO 2 can also attenuate myocardial injury caused by various harmful stimuli and play an important role in myocardial ischemia-reperfusion injury and myocardial hypertrophy. These effects are thought to be linked to its ability to reduce inflammation and as an antioxidant. In addition, SO 2 regulates cardiomyocyte apoptosis and autophagy. Therefore, endogenous SO 2 plays an important role in maintaining cardiovascular system homeostasis. In the present review, the literature concerning the metabolism of endogenous SO 2 , its cardiac toxicological effects and physiological regulatory effects, mechanisms for SO 2 -mediated myocardial protection and its pharmacological applications are summarized and discussed.