EFFECTS OF DIFFERENT INJURIOUS STIMULI ON CELL-DEATH, PROLIFERATION, AND COLLAGEN SECRETION BY RABBIT AORTIC SMOOTH-MUSCLE CELLS AND HUMAN UMBILICAL VEIN ENDOTHELIAL-CELLS IN CULTURE

Abstract

Rabbit aortic smooth muscle cells were exposed to hypoxia and the DMSO [dimethylsulfoxide]-soluble particulate matter of cigarette smoke (DSP) and the effects on the cells were compared to those of UV light, a well known cytotoxic stimulus. Hypoxia reduced cell proliferation and collagen secretion as long as it lasted (1, 3 and 24 h), but these effects were reversible and no persistent toxic effects were seen for the next 48 h, measured as leakage of prelabeled [3H]-thymidine from cells. DSP caused similar changes to those produced by UV-light. Proliferation and collagen secretion were reduced, and these effects were not reversible when the stimulus was removed after 1 h. DSP was toxic as there was an increased leakage of [3H]-thymidine from cells. Increasing the concentration of DSP caused more pronounced effects while extending the incubation time to 3 h did not, the latter being in contrast to the consequences of UV-irradiation. Endothelial cells were more sensitive to the effects of DSP than smooth muscle cells. DSP diluted 1:25 compared to the smallest concentration that had significant effects on smooth muscle cells reduced proliferation of endothelial cells, and in dilutions of 1:4 almost all of the cells detached. A possible role for DSP in the development of atherosclerosis is discussed.