Resveratrol decreases nitric oxide production by hepatocytes during inflammation.
BACKGROUND
The production of excessive amounts of nitric oxide (NO) through inducible nitric oxide synthase (iNOS) contributes to organ injury, inflammation, and mortality after shock. Resveratrol (RSV) is a natural polyphenol that decreases shock-induced hepatic injury and inflammation. We hypothesized that RSV would mediate these effects by decreasing hepatocyte iNOS production.


METHODS
Rat hepatocytes were isolated, cultured with varying concentrations of RSV, and then stimulated to induce iNOS with interleukin-1 and interferon. Induction of iNOS protein was measured by Western blot, iNOS mRNA by polymerase chain reaction, and NO production was measured by culture supernatant nitrite. Activation of intracellular signaling pathways involving Akt, c-Jun N-terminal kinase (JNK), and nuclear factor κB (NF-κB) were measured by Western blot using isoform-specific antibodies.


RESULTS
RSV decreased the expression of iNOS mRNA, protein, and supernatant nitrite in a dose-dependent manner. Our previous work demonstrated that Akt and JNK both inhibit hepatic iNOS production, whereas NF-κB increases iNOS expression. Analysis of signaling pathways in this study demonstrated that RSV increased JNK phosphorylation but decreased Akt phosphorylation and increased NF-κB activation.


CONCLUSIONS
RSV decreases cytokine-induced hepatocyte iNOS expression, possibly through up-regulation of the JNK signaling pathway. RSV merits further investigation to determine its mechanism as a compound that can decrease inflammation after shock.
The Hiram C. Polk Jr., MD Department of Surgery and Price Institute of Surgical Research, University of Louisville School of Medicine, Louisville, KY.
Charles W
CW
Kimbrough
The Hiram C. Polk Jr., MD Department of Surgery and Price Institute of Surgical Research, University of Louisville School of Medicine, Louisville, KY.
Jaganathan
J
Lakshmanan
The Hiram C. Polk Jr., MD Department of Surgery and Price Institute of Surgical Research, University of Louisville School of Medicine, Louisville, KY.
Paul J
PJ
Matheson
The Hiram C. Polk Jr., MD Department of Surgery and Price Institute of Surgical Research, University of Louisville School of Medicine, Louisville, KY.
Matthew
M
Woeste
The Hiram C. Polk Jr., MD Department of Surgery and Price Institute of Surgical Research, University of Louisville School of Medicine, Louisville, KY.
Andrea
A
Gentile
The Hiram C. Polk Jr., MD Department of Surgery and Price Institute of Surgical Research, University of Louisville School of Medicine, Louisville, KY.
Matthew V
MV
Benns
The Hiram C. Polk Jr., MD Department of Surgery and Price Institute of Surgical Research, University of Louisville School of Medicine, Louisville, KY.
Baochun
B
Zhang
The Hiram C. Polk Jr., MD Department of Surgery and Price Institute of Surgical Research, University of Louisville School of Medicine, Louisville, KY.
Jason W
JW
Smith
The Hiram C. Polk Jr., MD Department of Surgery and Price Institute of Surgical Research, University of Louisville School of Medicine, Louisville, KY. Electronic address: briang.harbrecht@louisville.edu.
Brian G
BG
Harbrecht
D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000494:pharmacology*; D015415:Biomarkers / Q000378:metabolism; D015153:Blotting, Western; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism; D007249:Inflammation / Q000378:metabolism*; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism*; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D051381:Rats; D017207:Rats, Sprague-Dawley; D000077185:Resveratrol; D015398:Signal Transduction / Q000187:drug effects; D013267:Stilbenes / Q000008:administration & dosage / Q000494:pharmacology*; D015854:Up-Regulation / Q000187:drug effects
D000894:Anti-Inflammatory Agents, Non-Steroidal; D015415:Biomarkers; D016207:Cytokines; D013267:Stilbenes; D009569:Nitric Oxide; D052247:Nitric Oxide Synthase Type II; D000077185:Resveratrol