Vairetti M, Richelmi P, Bertè F, Currin RT, Lemasters JJ, Imberti R. Role of pH in protection by low sodium against hypoxic injury in isolated perfused rat livers.
J Hepatol 2006;
44:894-901. [PMID:
16313996 DOI:
10.1016/j.jhep.2005.08.007]
[Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2004] [Revised: 07/31/2005] [Accepted: 08/16/2005] [Indexed: 12/04/2022]
Abstract
BACKGROUND/AIMS
The purpose of the present study was to characterize the role of Na+, pH and cellular swelling in the pathogenesis of hypoxic injury to rat livers.
METHODS AND RESULTS
When livers were perfused with hypoxic Krebs-Henseleit bicarbonate buffer (KHB) containing 143 mM Na+, release of LDH began after 30 min and was maximal after 60 min. In livers perfused with choline-substituted low-Na+ KHB (25 mM Na+), LDH release began after 60 min and peaked after 120 min or longer. Supplementation of KHB with mannitol, a permeant sugar with antioxidant properties, suppressed LDH release, whereas sucrose, an impermeant disaccharide, did not afford protection. At the end of hypoxic perfusions with KHB and low-Na+ KHB, liver weight was not different, whereas mannitol but not sucrose increased liver weight after hypoxia. At pH 7.4, monensin, a Na+-H+ ionophore, reversed protection against hypoxia by low-Na+ KHB (10 mM Na+) but had no effect at pH 6.8. As measured directly by confocal microscopy of biscarboxyethylcarboxyfluorescein fluorescence, pH was lower during perfusion with low-Na+ KHB than KHB.
CONCLUSIONS
Cytoprotection by low Na+ was not mediated by prevention of Na+-dependent tissue swelling. Rather, promotion of intracellular acidification likely mediates cytoprotection in low-Na+ buffer.
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