CYTOSKELETON OF RAT AORTIC SMOOTH-MUSCLE CELLS - NORMAL CONDITIONS AND EXPERIMENTAL INTIMAL THICKENING

  • 1 January 1984
    • journal article
    • research article
    • Vol. 50  (6) , 645-652
Abstract
The organization of actin, vimentin, and desmin in smooth muscle cells of rat aortic media and intima under normal conditions and 15 or 75 days after endothelial injury was studied by EM, indirect immunofluorescence, densitometric analysis on sodium dodecyl sulfate-polyacrylamide gels, isoelectric focusing, and bidimensional gels. In the normal aortic media, practically all smooth muscle cells contain vimentin, and 50% of them also contain desmin. Smooth muscle cells show a predominance of .alpha.-actin, some .beta.-actin, and very little .gamma.-actin. Fifteen days after endothelial injury, cells that have migrated into the intima contain decreased amounts of actin and desmin and increased amounts of vimentin compared with normal medial smooth muscle cells. Moreover, .beta.-actin becomes the predominant actin isotype and significant amounts of .gamma.-actin appear, whereas .alpha.-actin decreases. Seventy-five days after endothelial injury, regenerated endothelial cells have repaired the injury. Intimal smooth muscle cells are less numerous than 15 days after injury, and the organization of their cytoskeletal elements has reverted almost to normal conditions. At both 15 and 75 days after endothelial injury, no significant changes of cytoskeletal elements are seen in the aortic media underlying intimal thickenings.