Changes in [Ca 2+]i in cultured rat proximal tubular epithelium: an in vitro model for renal ischemia

Wei M. Chi, Irene K. Berezesky, Mary W. Smith, Benjamin F. Trump

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Two components of ischemia, oxygen deprivation and glycolytic inhibition, were studied in primary cultures of rat proximal tubular epithelial cells (PTE). Changes in cytosolic Ca2+ ([Ca2+]i) and its relationship to loss of mitochondrial membrane potential (ΔΨm,) and cell killing were characterized in single cells whereas ATP and LDH release were determined in populations of monolayer PTE. (1) Inhibition of mitochondrial respiration with KCN or anoxia resulted in little decrease in ATP or cell killing and slight change in [Ca2+]i over many hours. (2) Inhibition of respiration and glycolysis with anoxic HBSS minus glucose resulted in decreased ATP (54.4%) and cell killing (20%) during 5 h anoxic exposure. In all cases, but at highly variable times (113 ± 62 min), [Ca2+]i initially rose to > 1 μM. In some cases it immediately dropped, stabilizing at about 500 nM for up to 1 h and rising again just prior to cell death. (3) Inhibition with anoxia + 1 mM IAA resulted in rapid depletion of ATP and cell killing, with increases in [Ca2+ ]i to > 1 μM by 20 ± 2 min. (4) Depletion of glycolytic metabolites by depriving cells of substrate for 12 h (in HBSS minus glucose) before subjecting to anoxia minus glucose resulted in increases in [Ca2+ ]; at 40 ± 17 min followed by cell killing. (5) Injury with anoxic HBSS minus glucose was reversed by reaeration before or during the initial rise in [Ca2+]i. Later reaeration resulted in rapid cell killing. In all cases, ΔΨm was dissipated only after [Ca2+]i was significantly elevated.

Original languageEnglish
Pages (from-to)513-520
Number of pages8
JournalBiochimica et Biophysica Acta - General Subjects
Volume1243
Issue number3
DOIs
Publication statusPublished - Apr 13 1995
Externally publishedYes

Keywords

  • (Kidney)
  • Anoxia
  • Cytosolic calcium
  • Ischemia
  • Mitochondrion

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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