Kan-H; Antonini-JM; Ye-M; Zheng-W; Salmen-R; Popstojanov-R; Castranova-V
Toxicologist 2013 Mar; 132(1):242
Studies have found that pulmonary exposure to welding fumes is positively associated with a higher incidence of cardiovascular events. We reported previously that pulmonary exposure to welding fumes, manual metal arc-hard surfacing (MMAHS), has a negative impact on cardiac function as evidenced by reduced heart contractility. However, the mechanisms underlying MMA-HS-induced depression of cardiac contractility remain unclear. To study the mechanisms, rats were given an intratracheal instillation of MMA-HS welding fumes (2 mg/rat) or saline once a week for seven weeks. Cardiomyocytes were isolated at 1 and 7 days post-exposure. Cardiomyocyte contractility and intracellular calcium level in response to increasing concentrations of adrenoreceptor agonist isoprenaline and extracellular calcium were assessed using a Myocyte Calcium Imaging/Cell Length System. Pulmonary exposure to MMA-HS blunted contractile function in response to both isoprenaline and calcium at 1 day post-exposure (P < 0.01; P < 0.05, respectively). A blunted contractile response was also observed with welding fume treated rats at 7 days post-exposure in response to isoprenaline and calcium (P < 0.01). Intracellular calcium level in response to extracellular calcium stimulation was reduced at 7 days post-exposure (P < 0.05). These findings suggest that pulmonary exposure to welding fumes impairs cardiac function by decreasing cardiomyocyte contractility through a defect in the adrenergic signaling pathway and intracellular calcium handling.
Toxicology; Laboratory-animals; Exposure-assessment; Exposure-levels; Cardiovascular-function; Cardiovascular-system; Cardiovascular-system-disorders; Dose-response; Welders; Welding; Welding-industry; Arc-welding; Arc-welders; Fumes; Metal-fumes; Heart; Pulmonary-system; Cardiopulmonary-function; Cell-function; Cellular-function; Cellular-reactions; Cell-alteration; Cardiac-function; Calcium-compounds; Muscle-contraction
The Toxicologist. Society of Toxicology 52nd Annual Meeting and ToxExpo, San Antonio, Texas, March 10-14, 2013