Presence of titanium dioxide (TiO
) nanoparticles (NPs) in the rat ventricular myocardium after tracheal instillation: TEM analysis. A. Right Ventricle. Electron-dense NPs in two longitudinally oriented cardiomyocytes and in the wall of a vascular structure. B. Left Ventricle. NPs accumulating at the edge of longitudinally oriented cardiomyocytes, as well as in the sarcolemma. NPs are also present in the interstitial space, in endothelial cells and within the capillary lumen (L). C. Left ventricle. The lumen of a capillary neighboring a cardiomyocyte containing TiO2 NPs, which also appear to be connected to and engulfed by endothelial cells. GJ marks a gap junction location. Blue rectangles include areas shown at higher magnification in the lower panels (A1, B1 and C1). Scale Bars: A and B =5 μm; A1 and B1 = 2 μm; C =1 μm; C1 = 200 nm. Bottom. Ultrathin sections of lung samples from NP-exposed treated rats. D. The bronchial epithelium is apparent by the presence of ciliated cells (*). Electron-dense NPs are best seen in cytoplasm at high magnification (D1). Clusters of NPs were found within the lung parenchyma (E) and in macrophages (F). N, nucleus. G,H. The typical shape of titanium NPs is apparent at higher magnification. Scale Bars: D =5 μm; D1 = 2 μm; E =2 μm; F =1 μm; G =200 nm; H =100 nm.