Biophysical Journal 71: 91-100 (1996)
© 1996 the Biophysical Society

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Wu, Y Articles by Taylor, B M Search for Related Content PubMed PubMed Citation Articles by Wu, Y Articles by Taylor, B M

Changes in membrane properties during energy depletion-induced cell injury studied with fluorescence microscopy.

Pharmacia and Upjohn, Kalamazoo, Michigan 49001, USA.

ABSTRACT

The changes in membrane structural properties occurring during the process of ATP depletion-induced cell injury in adherent human astrocytoma cells (UC-11 MG) were studied with two epifluorescence techniques: 1) steady-state fluorescence anisotropy (r) to examine microstructural changes in the membrane phospholipids and 2) fluorescence redistribution after photobleaching (FRAP) to examine membrane fluidity changes. A new method for r measurement was established that provides the unique advantage of simultaneously monitoring both vertical and horizontal polarized fluorescence emissions needed for the calculation of r. In this study, r in the astrocytoma cells labeled with 1-(4-trimethylammonium phenyl)-6-phenyl-1,3,5-hexatriene p-toluenesulfonate was shown to remain stable for up to 90 min. However, when the cells were treated with 75 microM iodoacetic acid (IAA), a metabolic inhibitor that induces rapid depletion of cellular ATP, r continually decreased, indicating a decrease in membrane lipid order and perturbation of the bilayer structure. This decrease in r could be prevented by the pretreatment of cells with lipophilic antioxidants such as tirilazad or gossypol. Tirilazad itself caused a significant increase in r, suggesting that tirilazad intercalates into the membrane bilayer and profoundly increases the lipid order in uninjured cells. Gossypol, however, did not exhibit this property. Further investigations into these phenomena with FRAP confirmed the r results and indicated that membrane fluidity increased while its structure became less rigid during the process of ATP-induced cell injury. In addition, lipophilic antioxidants prevented the membrane structural aberrations induced by IAA. Experimental results suggest that different mechanisms of cytoprotective action may exist for tirilazad and the antioxidant gossypol. Gossypol appears to prevent or delay the observed cell injury entirely because of its antioxidant action, whereas tirilazad's protection is mediated not only via its antioxidant activity, but also by its ability to increase cell membrane lipid order.

This article has been cited by other articles:

				J. S. Goodwin, K. R. Drake, C. L. Remmert, and A. K. Kenworthy Ras Diffusion Is Sensitive to Plasma Membrane Viscosity Biophys. J., August 1, 2005; 89(2): 1398 - 1410. [Abstract] [Full Text] [PDF]

				P. M. Haggie and A. S. Verkman Diffusion of Tricarboxylic Acid Cycle Enzymes in the Mitochondrial Matrix in Vivo. EVIDENCE FOR RESTRICTED MOBILITY OF A MULTIENZYME COMPLEX J. Biol. Chem., October 18, 2002; 277(43): 40782 - 40788. [Abstract] [Full Text] [PDF]

				K.-T. Lin, J.-Y. Xue, M. C. Lin, E. G. Spokas, F. F. Sun, and P. Y.-K. Wong Peroxynitrite induces apoptosis of HL-60 cells by activation of a caspase-3 family protease Am J Physiol Cell Physiol, April 1, 1998; 274(4): C855 - C860. [Abstract] [Full Text] [PDF]