Cytochemical correlates of atherosclerosis-resistant and susceptible lesions of the normal rabbit aorta.
Quantitative cytochemical and microfluorimetric techniques were employed to compare mural intermediary metabolism--endothelial macromolecular uptake changes in spontaneous aortic-arteriosclerotic lesions of normolipemic New Zealand White rabbits. Specifically, mural succinic (SDH), lactic (LDH), and glucose-6-phosphate (G-6-PDH) dehydrogenase activities and luminal surface uptake of fluorescein isothiocyanate-conjugated bovine serum albumin (FITC-BSA) were measured in lesion sites abnormally resistant (calcified) and susceptible (proliferative) to dietary hypercholesterolemia. Calcified lesions exhibited severe (55-66%) diminution of SDH, LDH, and G-6-PDH activities within the involved inner mural zone and a comparable (68%) decline in luminal FITC-BSA uptake. Concomitant reductions in FITC-BSA uptake (30%) and marker enzymes of the predominant energy transducing pathways in arterial tissue, i.e., SDH (30%) and LDH (31%), were evidenced in proliferative foci, whereas G-6-PDH was augmented (52%) in comparison to nonlesioned aortic segments. These data lend additional support to the concept that endothelial uptake of plasma-borne macromolecules is coupled to oxidizable substrate requirements of inner avascular compartments of the arterial wall. It is postulated that diminished macromolecular transport in these degenerative lesions stems from reduced mural metabolic demands, and that pharmacologic reduction of vascular smooth muscle metabolism may depress uptake of sclerogenic macromolecules.
D000818:Animals; D001011:Aorta / Q000201:enzymology / Q000473:pathology; D001161:Arteriosclerosis / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D001692:Biological Transport; D005070:Evans Blue; D005260:Female; D005954:Glucosephosphate Dehydrogenase / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008297:Male; D011817:Rabbits; D012710:Serum Albumin, Bovine / Q000378:metabolism; D013385:Succinate Dehydrogenase / Q000378:metabolism
D012710:Serum Albumin, Bovine; D005070:Evans Blue; D007770:L-Lactate Dehydrogenase; D005954:Glucosephosphate Dehydrogenase; D013385:Succinate Dehydrogenase