FIGURE 7.

High resolution TEM images of ultrathin retinal sections at the level of the RPE (A,B) and of the INL (C,D). Images in (A,B) are from a Balb/c mouse retina, in which RPE cells do not contain pigment and therefore MNP-OCT can be easily detected. (B) is a higher power of the boxed area in (A). In the RPE, MNP-OCT were found to be internalized in several endocytic vesicles. The scission phase of endocytic process releasing primary endocytic vesicle is highlighted by arrowheads (B), while other MNP-containing vesicles are likely to represent different stages of the following intracellular trafficking (A,B, arrows). (D) is a higher power of the boxed area in (C). The nanoparticles in the INL were densely packed into narrow intercellular spaces (D, black arrows) or distributed in dense spots adjacent to the extracellular side of the plasma membrane of INL cells (D, red arrows). Scale bars, 1 μm in (A,B,D); 2 μm in (C).