CONICET | Buscador de Institutos y Recursos Humanos

LP diet induces ischemic renal injury involving epithelial cells from OSOM. Here, we tested whether HSP70 would stabilize renal Na+K+ATPase attachment to the cytoeskeleton during recovery from LP. After weaning, rats (n=8), were fed for 14 days with a LP diet (8%), then were recovered by means of a normal protein diet (24%RP) each group had an age-matched control group (24%, NP). Tissues from cortex and OSOM were homogeneized in buffer plus 0.1% Triton X-100. Protein levels were measured by Western blot. In vitro coincubation of solublen on cytoeskeletal and insoluble cytoskeletal-associated fractions in the presence or absence of anti-HSP70 antibody was performed. Interaction between proteins was determined by coimmunoprecipitation. Increased Na+K+ATPase dissociation was shown in soluble fraction from OSOM as a result of LP diet vs. NP (196.5±1.1 vs. 151±1.3, p<0.05). Meanwhile, decreased HSP70 levels in the same fraction was shown (LP: 179.3±10.5 vs. NP 224.7±1.85, p<0.05). Translocation of HSP70 to the cytoeskeletal injured fraction associated with stabilization of Na+K+ATPase was shown in OSOM from LP, after in vitro coincubation of the cytoskeletal fraction of LP and non cytoskeletal fraction of RP. These effects were abolished by the addition of anti-HSP70 antibody. Coimmunoprecipitation showed that the amount of HSP70 coprecipitating with Na+K+ATPase increased in LP OSOM, in RP results were similar to control. In cortex, absence of significant differences was shown in the Na+K+ATPase and HSP70 expression at in vivo and in vitro experiments among groups. In LP and RP cortex tissues, interaction of both proteins was similar to control. Our results allow us to suggest that HSP70 has a critical protective role in the integrity of the cytoskeletal anchorage of Na+K+ATPase during recovery from ischemic LP injury in OSOM.