Acute Effects of COREXIT EC9500A on Cardiovascular Functions in Rats

Abstract

These studies characterized cardiovascular responses after an acute inhalation exposure to COREXIT EC9500A, the oil dispersant used in the Deepwater Horizon oil spill. Male Sprague-Dawley rats underwent a single 5-h inhalation exposure to COREXIT EC9500A (average exposure level 27.12 mg/m(3)) or air. On d 1 and 7 following the exposure, rats were implanted with indwelling catheters and changes in heart rate and blood pressure were assessed in response to increasing levels of adrenoreceptor agonists. A separate group of rats was euthanized at the same time points, ventral tail arteries were dissected, and vascular tone along with dose-dependent responses to vasoconstricting and dilating factors were assessed in vitro. Agonist-induced dose-dependent increases in heart rate and blood pressure were greater in COREXIT EC9500A-exposed than in air-exposed rats at 1 d but not 7 d after the exposure. COREXIT EC9500A exposure also induced a rise in basal tone and reduced responsiveness of tail arteries to acetylcholine-induced vasodilation at 1 d but not 7 d following the exposure. These findings demonstrate that an acute exposure to COREXIT EC9500A exerts transient effects on cardiovascular and peripheral vascular functions.

A Computer-Controlled Whole-Body Inhalation Exposure System for the Oil Dispersant COREXIT EC9500A

“…The acute health effects observed for rats exposed to CE are examined in the companion articles described in this issue. These results showed a transient increase in heart rate and blood pressure, reduction in vascular responsiveness to vasodilating factors (Krajnak et al 2011), upregulation of the expression of the voltage-gated calcium channel Cav1.3, altered synaptic and cytoskeletal protein content in discrete brain areas (Sriram et al 2011), and negligible lung inflammation or injury ).…”

Gene Expression and Growth as Indicators of Effects of the BPDeepwater HorizonOil Spill on Spotted Seatrout (Cynoscion nebulosus)

“…The use of dispersants was also found to increase the bioavailability of PAH to fish (Ramachandran et al, 2004), which potentially amplifies effects of exposure to oil. Exposure to COREXIT resulted in altered immune (Anderson et al, 2011), neurotoxic (Sriram et al, 2011), cardiovascular (Krajnak et al, 2011), andpulmonary (Roberts et al, 2011) responses in rats.…”

Pulmonary and cardiovascular responses of rats to inhalation of a commercial antimicrobial spray containing titanium dioxide nanoparticles

“…The TiO 2 lung burden in the present study was 43 μg, while Nurkiewicz et al (2008) and LeBlanc et al (2009) noted microvascular dysfunction at nano TiO 2 lung burdens as low as 10 μg in systemic muscle and the heart, respectively. Although the tail artery model has been shown to be responsive to inhalation of irritants such as oil dispersant, and that these changes in microvessel responsiveness were accompanied by changes in heart rate and blood pressure (Krajnak et al, 2011), it may not be as sensitive as microvessel from other vascular beds. Indeed, coronary arterioles have been reported to be more sensitive to pulmonary exposure to nanoparticles than arterioles from the shoulder muscle of rats (LeBlanc et al, 2009).…”

“…PHEN was applied to the chamber in half-log increments (−8.5 to −6.0 M) and the internal diameter was recorded after vessels stabilized (approximately 5 min between application of doses). Because ventral tail arteries usually display little basal tone (Krajnak et al, 2011), endothelial-mediated redilation was assessed after constriction by adding Ach in half-log increments (−8.5 to −5.0) using the same procedures that were used to apply PHEN.…”