Translocation of HSP27 to cytoskeleton by repetitive hypoxia-reoxygenation in the rat myoblast cell line, H9c2.

We investigated the possible changes in the distribution of HSP27 after a brief hypoxia-reoxygenation stress in the rat myoblast cell line, H9c2, as a model of ischemic preconditioning. Cells were exposed to 4 cycles of 5 min. of hypoxia and 5 min. of reoxygenation. In the normoxic condition, HSP27 was exclusively found in the cytosolic fraction. After the hypoxia-reoxygenation cycle, HSP27 redistributed to the cytoskeletal fraction, which was blocked by 10 microM SB 203580, a specific inhibitor of p38 MAP kinase. Cells treated with the repetitive hypoxia-reoxygenation developed resistance against cell death induced by hypoxia for 24 hours. The changes in localization of HSP27 found in the present study may reflect the mechanism of preconditioning in the cardiac myocyte. Copyright 1998 Academic Press.