Figure 5.

Transmission electron microscopy. Representative aspects of the prestenotic segments of the aorta from operated rats and the corresponding segments from controls. The delicate structure of the intima from sham-operated rats contains flattened endothelial cells (end) and a very thin layer of support tissue (*). The intima is delimitated by the internal elastic lamina (iel) (a). In the prestenotic segment, the intima is thickened. The endothelial cells are heterogeneous, most of them with convoluted nuclei and cytoplasmic contours. Focal accumulation of mononuclear cells (mo) could be seen in the expanded intimal layer (b). Migration of smooth muscle cells from the media into the intima (arrow) through the fenestras of the internal elastic lamina (iel) can be also seen (c). The clusters of smooth muscle cells (smc) appear within the intima, randomly arranged and surrounded by collagen and elastic fibres (d). Scales bars = 10 μm.