Prophylactic proopiomelanocortin expression alleviates capsaicin-induced neurogenic inflammation in rat trachea

Shock. 2009 Dec;32(6):645-50. doi: 10.1097/SHK.0b013e3181a5aa10.

Abstract

Neurogenic inflammation frequently causes acute plasma leakage in airways and life-threatening pulmonary edema. However, limited strategies are available to alleviate neurogenic inflammation. Proopiomelanocortin (POMC) is the precursor of anti-inflammatory melanocortins, which have been proposed of therapeutic potential for various inflammatory diseases. The present study aimed to evaluate whether peripheral POMC expression ameliorated capsaicin-induced acute neurogenic inflammation in rat trachea. Prophylactic POMC expression was achieved by intravenous injection of adenovirus encoding POMC (Ad-POMC), which led to POMC expression in livers and elevated plasma adrenocorticotropin levels for approximately 60 days. After gene delivery for 7 days, neurogenic inflammation was induced in rats by capsaicin injection. The extent of capsaicin-evoked plasma leakage in trachea was alleviated in Ad-POMC-treated rats compared with animals of control groups (P < 0.01). Moreover, the number of endothelial gaps in tracheal venules was also significantly decreased in Ad-POMC-treated animals (P < 0.01). Prophylactic POMC expression, however, did not alter the basal substance P (SP) expression or the capsaicin-induced SP elevation in trachea and circulation. Instead, cell cultures studies revealed that POMC overexpression or application of POMC-derived melanocortins potently inhibited the SP-induced migration of endothelial cells (P < 0.01), thereby possibly contributing to the attenuation of endothelial gap formation and plasma leakage. The present study indicates that the anti-inflammatory POMC gene vector or melanocortins may constitute a therapeutic alternative for neurogenic inflammation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents / pharmacology
  • Capsaicin / pharmacology*
  • Cell Line
  • Cell Movement
  • Gene Expression Regulation*
  • Humans
  • Inflammation / chemically induced*
  • Male
  • Melanocortins / chemistry
  • Pro-Opiomelanocortin / biosynthesis*
  • Rats
  • Rats, Sprague-Dawley
  • Time Factors
  • Trachea / drug effects*
  • Trachea / physiopathology

Substances

  • Anti-Inflammatory Agents
  • Melanocortins
  • Pro-Opiomelanocortin
  • Capsaicin