Acute pulmonary and moderate cardiovascular responses of spontaneously hypertensive rats after exposure to single-wall carbon nanotubes. 
As a novel kind of nanomaterial with wide potential applications, the adverse effects of carbon nanotubes (CNTs) have recently received significant attention after respiratory exposure.  In this study, single-wall carbon nanotubes (SWCNTs) containing different metal contents were intratracheally instilled into lungs of spontaneously hypertensive rats.  Pulmonary and cardiovascular system alterations were evaluated at 24 and 72 h post-instillation.  Biomarkers of inflammation, oxidative stress and cell damage in the bronchoalveolar lavage fluid (BALF) were increased significantly 24 h post-exposure of SWCNTs.  The increased endothelin-1 levels in BALF and plasma and angiotensin I-converting enzyme in plasma suggested endothelial dysfunction in the pulmonary circulation and peripheral vascular thrombosis.  These findings suggest that respiratory exposure to SWCNTs can induce acute pulmonary and cardiovascular responses and individuals with existing cardiovascular diseases are very susceptible to SWCNTs exposure.  The co-existence of metal residues in SWCNTs can aggravate the adverse effects.