RELEASE OF FIBRONECTIN, SULFATED GLYCOSAMINOGLYCANS AND β-HEXOSAMINIDASE FROM INJURED SMOOTH MUSCLE CELLS AND FIBROBLASTS IN CULTURE - POSSIBLE TRANSFERABLE EFFECTS ON NEW CULTURES

The effect of injury to the bovine arterial smooth muscle cell in vitro was studied. Injury was caused by dimethylsulphoxide-soluble particles from cigarette smoke. The release of fibronectin was studied with human skin fibroblasts, but all other experiments on bovine myocytes. Fibronectin release was increased from injured cells, while that of sulfated glycosaminoglycans was decreased. These changes in release were evident already during the first hour after injury, while the increased release of the lysosomal enzyme β-hexosaminidase was manifest 1–24 hours after injury, but not during the first hour. Conditioned medium from injured cells was toxic to new cultures. This toxicity could be prevented by including the protease inhibitor α1-antitrypsin to the cultures exposed to smoke particles. When α1-antitrypsin was added first after the cells had been exposed to the smoke particles it was without effect. The free radical scavenger vitamin E was without effect. Cell detachment was a good index of cell death after exposure to cigarette smoke particles, as judged from the simultaneous measurement of DNA content and trypan blue uptake. During the period 24 hours after the toxic influence of cigarette smoke particles on original cultures, or 24 hours after the action of conditioned medium on new cultures, the injured cells revealed an augmented DNA synthesis compared to controls. The injured cells were, however, less responsive to growth-stimulating activity from platelets.