Sodium sulfite mediated oxidative stress triggers cardiac mast cell degranulation

Abstract

Exposure to elevated levels of airborne pollutants causes cardiac mast cell activation. Sulfur dioxide, a derived from fossil fuel combustion, has been shown to induce mast cell degranulation in an immortalized cell line. However, it is not known whether sulfur dioxide induced oxidative stress can directly trigger the activation of cardiac mast cells. This study sought to determine if ionization of sodium sulfite (Na2SO3) can induce degranulation of cardiac mast cells, and whether mast cell activation can be prevented by inhibition of oxidative stress. Cardiac mast cells were isolated from the pericardial sac and incubated with increasing concentrations of Na2SO3. Antioxidant compounds targeting different mechanisms of free radical generation, including ebselen, dyphenyleneiodinium (DPI) and tocopherol, were incubated with Na2SO3 in order to determine their efficacy in preventing mast cell degranulation. Sodium sulfite induced a concentration-dependent histamine release from cardiac mast cells which was prevented by ebselen and attenuated by DPI. In contrast, the histamine release was exacerbated by tocopherol. These findings indicate that sulfur dioxide is capable of causing cardiac mast cell degranulation and the variable effectiveness of the antioxidants evaluated is indicative of a multifactorial mechanism mediating sulfur dioxide induced cardiac mast cell degranulation. EPA grant RD-83195301 (GLB)