An immunocytochemical and cytochemical study has been made on
the ultrastructural localisation of type III (endothelial) nitric oxide
synthase, endothelin-1 and the binding sites of lectin from
Bandeirea simplicifolia to the endothelium surface-associated
glycoproteins in the rat left common carotid artery at 1 and 28 d after
Fogarty embolectomy balloon catheter-induced injury. Controls were
carotid arteries from sham operated rats. In the controls, the
immunoreactivity to nitric oxide synthase-III and endothelin-1 was
localised in different proportions in vascular endothelial cells
(36·9%±4·3 and 7·6%±2·7,
respectively); immunoreactivity was confined to the cytoplasm and the
membranes of intracellular organelles and structures. In contrast,
staining with lectin was localised on the luminal surface of all
endothelial cells. 1 d after injury, platelets were adherent to the
endothelium-denuded intima. Some of the platelets displayed
immunoreactivity to nitric oxide synthase-III and endothelin-1 and were
stained with lectin. 28 d after injury, a neointimal thickening of
substantial size was present. Subpopulations of the regrown endothelial
cells covering the luminal surface of the neointima showed positive
immunoreactivity to nitric oxide synthase-III and endothelin-1 but
there was a significant decrease in the proportion of nitric oxide
synthase-III-containing endothelial cells
(17·2%±1·9; P < 0·001) and a
significant increase in the proportion of endothelin-1-containing
endothelial cells (36·9%±4·7; P <
0·001) compared with the controls. Staining with lectin was
associated with the cell membrane of all endothelial cells and in
addition with cells located ‘deeper’ in the neointima which
showed lectin-positive plasmalemma, Golgi complex and multivesicular
bodies/lysosomes. In conclusion, regenerated endothelial cells of
the neointima showed reduced population (2–fold) of nitric oxide
synthase-III- and increased population (5–fold)
endothelin-1-positive cells. The subendothelial location of some
lectin-stained cells after balloon catheter injury indicates the
heterogeneity of the neointima and suggests that some of these cells
are involved in early angiogenesis. 24 h and 28 d after injury some
platelets showed positive immunoreactivity for nitric oxide
synthase-III and endothelin-1.