Ischemic conditioning prevents Na,K-ATPase dissociation from the cytoskeletal cellular fraction after repeat renal ischemia in rats

Pediatr Res. 2002 Jun;51(6):722-7. doi: 10.1203/00006450-200206000-00010.


Recent studies have suggested that heat shock proteins (HSPs) are involved in the restoration of the cytoskeletal anchorage of Na,K-ATPase after renal ischemia. To determine their role in ischemic conditioning, we investigated whether cytoskeletal Na,K-ATPase was stabilized during repeat ischemia concurrent with 25-kD and 70-kD HSPs induction. Anesthetized rats either underwent single unilateral renal ischemia or were conditioned with bilateral renal ischemia and, after 18 h of reflow, were then subjected to repeat unilateral renal ischemia. Renal cortex was harvested, and effects of single versus repeat ischemia were compared by Triton X-100 extraction, by immunohistochemistry, and by an in vitro assay of Na,K-ATPase association with isolated cytoskeletal fractions. In contrast to single ischemia, repeat ischemia did not result in increased Triton X-100 extractability of Na,K-ATPase. Levels of 25-kD and 70-kD HSPs were significantly induced by ischemic conditioning and redistributed into the cytoskeletal fraction after single and repeat ischemia. Immunohistochemistry also showed significant disruption of Na,K-ATPase within proximal tubules only after a single episode of ischemia, whereas repeat ischemia did not alter the pattern of restored Na,K-ATPase localization in conditioned renal cortex. The preserved association of Na,K-ATPase with the cytoskeletal fraction of conditioned renal cortex was effectively abolished in vitro by addition of antibodies against 25-kD or 70-kD HSP. These results suggest that 25-kD and 70-kD HSPs induced by ischemic conditioning stabilize the cytoskeletal anchorage of Na,K-ATPase during repeat renal ischemia.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Fractionation
  • Cytoskeleton
  • HSP27 Heat-Shock Proteins
  • HSP70 Heat-Shock Proteins / metabolism
  • Heat-Shock Proteins*
  • Ischemia / metabolism*
  • Ischemia / physiopathology
  • Ischemic Preconditioning*
  • Kidney Cortex / enzymology*
  • Kidney Cortex / physiopathology
  • Luminescent Measurements
  • Male
  • Neoplasm Proteins / metabolism
  • Rats
  • Rats, Sprague-Dawley
  • Sodium-Potassium-Exchanging ATPase / metabolism*


  • HSP27 Heat-Shock Proteins
  • HSP70 Heat-Shock Proteins
  • Heat-Shock Proteins
  • Hspb1 protein, rat
  • Neoplasm Proteins
  • Sodium-Potassium-Exchanging ATPase