Abstract
Ethyl pyruvate (EP) solution ameliorates ileal mucosal hyperpermeability and decreases the expression of several proinflammatory genes in ileal and/or colonic mucosa when it is used instead of Ringer's lactate solution (RLS) to resuscitate mice from hemorrhagic shock. To test the hypothesis that EP can ameliorate gut barrier dysfunction induced by other forms of inflammation, we incubated Caco-2 monolayers for 24 to 48 h with cytomix (a mixture of interferon-γ, tumor necrosis factor-α, and interleukin-1β) in the presence or absence of graded concentrations of EP or sodium pyruvate. Cytomix increased the permeability of Caco-2 monolayers to fluorescein isothiocyanate-labeled dextran (FD4; average molecular mass 4 kDa), but this effect was inhibited by adding 0.1 to 10 mM EP (but not similar concentrations of sodium pyruvate) to the culture medium. EP inhibited several other cytomix-induced phenomena, including nuclear factor-κB activation, inducible nitric oxide synthase mRNA expression, and nitric oxide production. Cytomix altered the expression and localization of the tight junctional proteins, ZO-1 and occludin, but this effect was prevented by EP. Delayed treatment with EP solution instead of RLS ameliorated ileal mucosal hyperpermeability to FD4 and bacterial translocation to mesenteric lymph nodes in mice challenged with lipopolysaccharide (LPS). These data support the view that EP ameliorates cytokine- and/or LPS-induced derangements in intestinal epithelial barrier function.
Footnotes
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This work was supported by grants from the National Institutes of Health (GM53789, GM37631, and GM58484) and DARPA (N65236-00-1-5434).
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DOI: 10.1124/jpet.102.043182
- Abbreviations:
- ROS
- reactive oxygen species
- EP
- ethyl pyruvate
- RLS
- Ringer's lactate solution
- NF-κB
- nuclear factor-κB
- iNOS
- inducible nitric oxide synthase
- TNF-α
- tumor necrosis factor-α
- IL
- interleukin
- LPS
- lipopolysaccharide
- IFN-γ
- interferon-γ
- DMEM
- Dulbecco's minimal essential medium
- PBS
- phosphate-buffered saline
- FBS
- fetal bovine serum
- Ab
- antibody
- FD4
- fluorescein isothiocyanate-labeled dextran
- PMSF
- phenylmethylsulfonyl fluoride
- DTT
- dithiothreitol
- EMSA
- electrophoretic mobility shift assay
- RT-PCR
- reverse transcription-polymerase chain reaction
- TBS
- Tris-buffered saline
- PBST
- PBS containing 0.02% Tween 20
- ALT
- alanine aminotransferase
- KHBB
- Krebs-Henseleit bicarbonate buffer
- MP
- methyl pyruvate
- NO2−
- nitrite
- NO3−
- nitrate
- CYTO
- cytomix
- KCN
- potassium cyanide
- Received August 14, 2002.
- Accepted September 25, 2002.
- The American Society for Pharmacology and Experimental Therapeutics
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