Impact of Intratracheal Administration of Polyethylene Glycol-Coated Silver Nanoparticles on the Heart of Normotensive and Hypertensive Mice

Abstract

Silver nanoparticles are widely used in various industrial and biomedical applications; however, little is known about their potential cardiotoxicity after pulmonary exposure, particularly in hypertensive subjects. We assessed the cardiotoxicity of polyethylene glycol (PEG)-coated AgNPs in hypertensive (HT) mice. Saline (control) or PEG–AgNPs (0.5 mg/kg) were intratracheally (i.t.) instilled four times (on days 7, 14, 21, and 28 post-angiotensin II or vehicle [saline] infusion). On day 29, various cardiovascular parameters were evaluated. Systolic blood pressure and heart rate were higher in PEG–AgNPs-treated HT mice than in saline-treated HT or PEG–AgNPs-treated normotensive mice. The heart histology of PEG–AgNPs-treated HT mice had comparatively larger cardiomyocyte damage with fibrosis and inflammatory cells when compared with saline-treated HT mice. Similarly, the relative heart weight and the activities of lactate dehydrogenase and creatine kinase-MB and the concentration of brain natriuretic peptide concentration were significantly augmented in heart homogenates of HT mice treated with PEG–AgNPs compared with HT mice treated with saline or normotensive animals exposed to PEG–AgNPs. Similarly, the concentrations of endothelin-1, P-selectin, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1 in heart homogenates were significantly higher than in the other two groups when HT mice were exposed to PEG–AgNPs. Markers of inflammation and oxidative and nitrosative stress were significantly elevated in heart homogenates of HT mice given PEG–AgNPs compared with HT mice treated with saline or normotensive animals exposed to PEG–AgNPs. The hearts of HT mice exposed to PEG–AgNPs had significantly increased DNA damage than those of HT mice treated with saline or normotensive mice treated with AgNPs. In conclusion, the cardiac injury caused by PEG–AgNPs was aggravated in hypertensive mice. The cardiotoxicity of PEG–AgNPs in HT mice highlights the importance of an in-depth assessment of their toxicity before using them in clinical settings, particularly in patients with pre-existing cardiovascular diseases.