Cytochalasin delays but does not prevent cell death from anoxia.

The role of alterations in the cytoskeleton in the anoxic death of cultured hepatocytes was evaluated with the use of cytochalasin B and colchicine. The addition of 50 microM Cytochalasin did, however, reduce the rate of accumulation of dead cells but was without effect on the number of cells that died. After 6 hours of anoxia in the presence of cytochalasin, 80% of the cells were dead. The same number of cells were dead after 4 hours in the absence of cytochalasin. Colchicine was without effect on the cell killing by anoxia. Cytochalasin also did not prevent the increase in the molecular order of the membranes of the anoxic hepatocytes as determined by electron spin resonance spectroscopy. In the presence or absence of cytochalasin, anoxia increased the order parameter, S, of hepatocytes spin-labeled with 12-doxyl stearic acid. These data indicate that changes in the organization of microfilaments that can be prevented by cytochalasin may aggravate the mechanisms mediating the anoxic death of the hepatocytes, but such mechanisms are essentially independent of these alterations in the cytoskeleton. The data do not exclude from a role in anoxic cell death other cytoskeletal changes that may not be affected by either cytochalasin or colchicine.