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ACID-FUNCTIONALIZED SINGLE-WALLED CARBON NANOTUBES ENHANCE CARDIAC ISCHEMIC/REPERFUSION INJURY
Citation:
TONG, H., M. I. GILMOUR, R. B. DEVLIN, AND R. SAXENA. ACID-FUNCTIONALIZED SINGLE-WALLED CARBON NANOTUBES ENHANCE CARDIAC ISCHEMIC/REPERFUSION INJURY. Presented at Americna Heart Associaiton Scientific Sessions, Orlando, FL, November 04 - 07, 2007.
Impact/Purpose:
The present study was designed to evaluate the cardiac effects of single-walled carbon nanobubes on ischemic/reperfusion injury.
Description:
Engineered nanotubes are being intensively developed for biomedical applications such as gene and drug delivery. Because of their unique properties, nanotubes can impose some potentially toxic effects, particularly if they have been modified to express functionally reactive chemical groups on their surface. Pulmonary toxicity has been documented; however, cardiovascular toxicity following pulmonary exposure to nanotubes has not been reported. The present study was designed to evaluate the cardiac effects of single-walled carbon nanobubes on ischemic/reperfusion injury. We exposed mice to 40 g of single-walled carbon nanotubes (SWNT), acid-functionalized nanotubes (AF-SWNT), or saline by intratracheal instillation. Twenty-four hours later, Langendorff-perfused mouse hearts were perfused for 25 minutes prior to 20 minutes of global ischemia followed by 2 hours of reperfusion. Recovery of left ventricular developed pressure (LVDP) and infarct size were measured after 1 and 2 hours of reperfusion respectively. Coronary flow rate was measured before, during, and after ischemia. Hearts from acid-functionalized SWNT-exposed mice had significantly lower functional recovery (17.8±5.5% for AF-SWNT vs. 44.0±5.6% for saline, p<0.05) and greater infarct size (56.0±3.3% for AF-SWNT vs. 37.5±6.8% for saline, p<0.05) than that of saline hearts. Hearts from SWNT exposed mice had no significant effects on functional recovery (28.6±3.2%) and infarct size (31.2±5.0%). We also found that acid-functionalized SWNT-exposed hearts had significantly higher coronary 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 adverse effect was due to the inflammatory effect of nanotubes, we exposed mice to 2 g of LPS and we found no significant effects of LPS on cardiac ischemic/reperfusion injury. This study indicated that exposure to acid-functionalized SWNT enhanced cardiac ischemic/reperfusion injury in mice. This proposed abstract does not necessarily reflect EPA policy.