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ACID FUNCTIONALIZED SINGLE-WALLED CARBON NANOTUBES ENHANCE CARDIAC ISCHEMIC/REPERFUSIOIN INJURY
Citation:
TONG, H., M. I. GILMOUR, M. J. DANIELS, E. BOYKIN, U. KODVANTI, R. B. DEVLIN, AND R. SAXENA. ACID FUNCTIONALIZED SINGLE-WALLED CARBON NANOTUBES ENHANCE CARDIAC ISCHEMIC/REPERFUSIOIN INJURY. Presented at Society of Toxicology 47th Annual Meeting, Seattle, WA, March 16 - 20, 2008.
Impact/Purpose:
This study indicates that exposure to AF-SWNTs enhanced cardiac ischemic/reperfusion injury in mice.
Description:
Engineered carbon nanotubes are being intensively developed for wide applications. Because of their unique light properties, nanotubes can impose some potentially toxic effects, particularly if they have been modified to express functionally reactive chemical groups on their surface to increase their dispersibility. The present study was designed to evaluate the cardiac effects of acid-functionalized single-walled carbon nanotubes (AF-SWNTs) on ischemic/reperfusion injury. We exposed mice to 40 g of SWNTs, AF-SWNTs, or saline by intratracheal instillation. Twenty-four h later, mouse hearts were perfused using Langendorff system for 25 min prior to 20 min of global ischemia followed by 2 h of reperfusion. Recovery of left ventricular developed pressure (LVDP) and infarct size were measured at 1 and 2 h of reperfusion respectively. Coronary artery flow rate was measured before, during, and after ischemia. Hearts from AF-SWNTs-exposed mice had significantly lower functional recovery (17.8±5.5% vs. 44.0±5.6% for saline, p<0.05) and greater infarct size (56.0±3.3 vs. 37.5±6.8% for saline, p<0.05) relative to controls. Hearts from SWNTs exposed mice had no significant effects on functional recovery (28.6±3.2%) and infarct size (31.2±5.0%) relative to controls. We also found that AF-SWNTs-exposed hearts had significantly higher coronary artery flow rate before ischemia (6.2±0.4 ml/min) than that of saline (3.0±0.2, p<0.05 vs. AF-SWNT) and SWNT hearts (3.4±0.4, p<0.05 vs. AF-SWNT). To determine whether the acid-functionalized groups contributed to the cardiac toxicity, we exposed mice to ultrafine carbon black (UFCB) and acid-functionalized UFCB (AF-UFCB). We found that treatment with AF-UFCB resulted in significant pulmonary injury, but no cardiac toxicity. To examine whether the adverse cardiac effect was due to the inflammatory effect of nanotubes, we exposed mice to LPS but found no significant effects on cardiac function. This study indicates that exposure to AF-SWNTs enhanced cardiac ischemic/reperfusion injury in mice. This proposed abstract does not reflect EPA policy.