Open AccessTumor Necrosis Factor Alpha Inhibits Hepatocyte Mitochondrial Respiration
Author(s) -
J. Stadler,
Brandon G. Bentz,
Brian G. Harbrecht,
Mauricio Di Silvio,
Ronald Curran,
Timothy R. Billiar,
Rosemary A. Hoffman,
Richard L. Simmons
Publication year - 1992
Publication title -
annals of surgery
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 4.153
H-Index - 309
eISSN - 1528-1140
pISSN - 0003-4932
DOI - 10.1097/00000658-199211000-00003
Subject(s) - medicine , tumor necrosis factor alpha , alpha (finance) , respiration , hepatocyte , necrosis , mitochondrion , microbiology and biotechnology , cancer research , endocrinology , biochemistry , anatomy , surgery , biology , construct validity , patient satisfaction , in vitro
Although direct cytotoxicity is a well-established phenomenon of tumor necrosis factor alpha (TNF alpha)-induced tissue damage, the intracellular events leading to cell death are still poorly understood. To study the cytotoxic effects of TNF alpha on normal parenchymal cells, rat hepatocytes were purified and incubated with various concentrations of TNF alpha. Mitochondrial respiration, total protein synthesis, and enzyme release were measured to assess metabolic performance and cell integrity. Treatment with TNF alpha suppressed mitochondrial respiration in a concentration-dependent fashion, resulting in a reduction of the activity of complex I of the respiratory chain to 67.0 +/- 3.5% of that of untreated hepatocytes by 2000 U/mL TNF alpha. Under these conditions protein synthesis and the release of intracellular enzymes were significantly increased. Both hepatocellular enzyme release and inhibition of mitochondrial respiration appear to be associated with the generation of reactive oxygen intermediates by the hepatocyte itself, because oxygen radical scavengers prevented these adverse effects of TNF alpha. Inhibition of protein synthesis by cycloheximide as well as addition of cyclic adenosine monophosphate synergistically enhanced the suppression of mitochondrial respiration by TNF alpha, resulting in complex I activity of 6.9 +/- 1.6% and 24.9 +/- 2.9% of that of untreated cells. These data indicate that inhibition of mitochondrial respiration is one of the mechanisms by which TNF alpha induces tissue injury.