The Tohoku Journal of Experimental Medicine
Online ISSN : 1349-3329
Print ISSN : 0040-8727
ISSN-L : 0040-8727
Regular Contributions
Growth Hormone Releasing Peptide-2, a Ghrelin Agonist, Attenuates Lipopolysaccharide-Induced Acute Lung Injury in Rats
Guang LiJianguo LiQing ZhouXuemin SongHui LiangLili Huang
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JOURNAL FREE ACCESS

2010 Volume 222 Issue 1 Pages 7-13

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Abstract

Acute lung injury (ALI) and its severe form, acute respiratory distress syndrome (ARDS), are the most common complications of sepsis, and the mortality of sepsis-induced ALI remains high in critically ill patients. Growth hormone releasing peptide-2 (GHRP-2), a ghrelin agonist, has been shown to exert beneficial effects on various inflammatory diseases. We therefore explored whether GHRP-2 possesses anti-inflammatory properties in the pathogenesis of lipopolysaccharide (LPS)-induced ALI. Male Sprague-Dawley rats were intratracheally instilled with LPS (2 mg/kg) to induce ALI. ALI was confirmed with lung tissue injury (histopathological examination), enhanced lung edema (wet-to-dry weight ratio), and neutrophil infiltration (myeloperoxidase activity) at 6 h after LPS exposure. The analyses of bronchoalveolar lavage fluid showed the significant increases in pulmonary permeability (total cells and protein) and the levels of proinflammatory cytokines, including tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6). In contrast, these lung injury indexes were attenuated in rats that received a subcutaneous injection of GHRP-2 (100 μg/kg) 0.5 h prior to LPS administration. To further explore the potential anti-inflammatory mechanism of GHRP-2 in LPS-induced ALI, we assessed of nuclear factor-κB (NF-κB) activity in lung tissues at 6 h after LPS challenge. We thus found that pretreatment with GHRP-2 markedly suppressed the activation of NF-κB in lung tissues. These results indicate that GHRP-2 attenuated LPS-induced ALI. Early protection appears to be mediated partly through the inhibition of NF-κB pathway activation. The present study indicates that GHRP-2 acts as a potential therapeutic reagent for treating ALI.

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© 2010 Tohoku University Medical Press
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