Role of gut flora on intestinal group II phospholipase A2 activity and intestinal injury in shock

Am J Physiol Gastrointest Liver Physiol. 2001 Oct;281(4):G957-63. doi: 10.1152/ajpgi.2001.281.4.G957.


We previously showed that group II phospholipase A2 (PLA2-II), a secretory, bactericidal, and proinflammatory protein in intestinal crypts, is upregulated after lipopolysaccharide (LPS) and platelet-activating factor (PAF) challenge. Here we examined whether germ-free environment (GF) or antibiotic treatment (ABX) affects the pathophysiological responses and intestinal PLA2-II activity after PAF (1.5 microg/kg) or LPS (8 mg/kg) injection. We found that LPS and PAF induced hypotension and mild intestinal injury in conventionally fed (CN) rats; these changes were milder in ABX rats, whereas GF rats showed no intestinal injury. PLA2-II enzyme activity was detected in normal rat small intestine; the basal level was not diminished in ABX or GF rats. PAF and LPS caused an increase in PLA2-II activity, which was abrogated in GF and ABX rats. Recolonization of GF rats by enteral contamination restituted their PLA2-II response to PAF and LPS and susceptibility to bowel injury. We conclude that PAF- and LPS-induced increases in PLA2-II activity are dependent on gut bacteria, and ABX and GF rats are less susceptible to LPS-induced injury than CN rats.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Anti-Bacterial Agents / pharmacology
  • Bacterial Physiological Phenomena*
  • Blood Pressure / drug effects
  • Germ-Free Life
  • Group II Phospholipases A2
  • Hematocrit
  • Intestine, Small / drug effects
  • Intestine, Small / enzymology
  • Intestine, Small / microbiology*
  • Intestine, Small / pathology
  • Leukocyte Count
  • Lipopolysaccharides / pharmacology*
  • Male
  • Phospholipases A / metabolism*
  • Phospholipases A2
  • Platelet Activating Factor / pharmacology*
  • Rats
  • Rats, Sprague-Dawley
  • Shock, Septic / enzymology
  • Shock, Septic / microbiology*
  • Shock, Septic / pathology


  • Anti-Bacterial Agents
  • Lipopolysaccharides
  • Platelet Activating Factor
  • Phospholipases A
  • Group II Phospholipases A2
  • Phospholipases A2