A novel fluid resuscitation strategy modulates pulmonary transcription factor activation in a murine model of hemorrhagic shock.
BACKGROUND
Combining the hemodynamic and immune benefits of hypertonic saline with the anti-inflammatory effects of the phosphodiesterase inhibitor pentoxifylline (HSPTX) as a hemorrhagic shock resuscitation strategy reduces lung injury when compared with the effects of Ringer's lactate (RL). We hypothesized that HSPTX exerts its anti-inflammatory effects by interfering with nuclear factor kappa B/cAMP response element-binding protein (NF-kappaB-CREB) competition for the coactivator CREB-binding protein (CBP) in lung tissue, thus affecting pro-inflammatory mediator production.


METHODS
Male Sprague-Dawley rats underwent 60 minutes of hemorrhagic shock to reach a mean arterial blood pressure of 35 mmHg followed by resuscitation with either RL or HSPTX (7.5% HS + 25 mg/kg PTX). After four hours, lung samples were collected. NF-kappaB activation was assessed by measuring the levels of phosphorylated cytoplasmic inhibitor of kappa B (I-kappaB) and nuclear NF-kappaB p65 by western blot. NF-kappaB and CREB DNA-binding activity were measured by electrophoretic mobility shift assay (EMSA). Competition between NF-kappaB and CREB for the coactivator CBP was determined by immunoprecipitation. Interleukin-8 (IL-8) levels in the lung were measured by ELISA.


RESULTS
RL resuscitation produced significantly higher levels of lung IL-8 levels, I-kappaB phosphorylation, p65 phosphorylation, and NF-kappaB DNA binding compared with HSPTX. NF-kappaB-CBP-binding activity was similar in both groups, whereas CREB-CBP-binding activity was significantly increased with HSPTX. CREB-DNA binding-activity increased to a greater level with HSPTX compared with RL.


CONCLUSIONS
HSPTX decreases lung inflammation following hemorrhagic shock compared with conventional resuscitation using RL through attenuation of NF-kappaB signaling and increased CREB-DNA binding activity. HSPTX may have therapeutic potential in the attenuation of ischemia-reperfusion injury observed after severe hemorrhagic shock.
Costantini
Todd W
TW
University of California San Diego School of Medicine, California, USA.
Deree
Jessica
J
Martins
J O
JO
Putnam
James G
JG
Campos
Tercio de
Td
Coimbra
Raul
R
D000818:Animals; D000893:Anti-Inflammatory Agents / Q000627:therapeutic use; D004195:Disease Models, Animal; D018836:Inflammation Mediators / Q000378:metabolism*; D008168:Lung / Q000378:metabolism* / Q000473:pathology; D008297:Male; D016328:NF-kappa B / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D010431:Pentoxifylline / Q000627:therapeutic use; D010726:Phosphodiesterase Inhibitors / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000188:drug therapy / Q000378:metabolism; D012151:Resuscitation / Q000379:methods; D012462:Saline Solution, Hypertonic / Q000627:therapeutic use; D012771:Shock, Hemorrhagic / Q000150:complications / Q000378:metabolism / Q000628:therapy*; D014157:Transcription Factors / Q000378:metabolism*
D000893:Anti-Inflammatory Agents; D018836:Inflammation Mediators; D016328:NF-kappa B; D009687:Nuclear Proteins; D010726:Phosphodiesterase Inhibitors; D012462:Saline Solution, Hypertonic; D014157:Transcription Factors; D010431:Pentoxifylline