Post-capillary venules in the "milky spots" of the greater omentum are the major site of plasma protein and leukocyte extravasation in rodent models of peritonitis

Inflamm Res. 1995 Apr;44(4):169-77. doi: 10.1007/BF01782815.


Intraperitoneal injection of inflammatory agents in the mouse and rat causes plasma protein and leukocyte extravasation into the peritoneal cavity. Following an intraperitoneal injection of zymosan A, the milky spots of the omentum were the only abdominal sites detected where intravenously administered Monastral Blue labeled interendothelial cell gaps responsible for plasma extravasation. In addition, when colored microspheres were intraventricularly administered to quantify blood flow, the omentum was the only abdominal organ which showed an increase in blood flow during zymosan A peritonitis. A combination of light and electron microscopy, plus measurement of myeloperoxidase activity (a marker of neutrophil accumulation) demonstrated that the omental milky spots are the major route through which leukocytes migrate into the peritoneal cavity. Identical structures in the pleura likewise are the sites of protein leakage into the pleural cavity. In contrast, selective sites of protein and cellular extravasation could not be detected in the synovial lining of the inflamed knee joint.

MeSH terms

  • Animals
  • Arthritis / chemically induced
  • Arthritis / pathology
  • Blood Flow Velocity
  • Blood Proteins / metabolism*
  • Disease Models, Animal
  • Indoles
  • Leukocytes / metabolism*
  • Male
  • Mice
  • Microscopy, Electron
  • Omentum / blood supply*
  • Organometallic Compounds
  • Peritoneum / metabolism
  • Peritoneum / pathology
  • Peritonitis / chemically induced
  • Peritonitis / metabolism*
  • Peritonitis / pathology
  • Pleurisy / chemically induced
  • Pleurisy / pathology
  • Rats
  • Staining and Labeling
  • Venules / metabolism*
  • Zymosan


  • Blood Proteins
  • Indoles
  • Organometallic Compounds
  • copper phthalocyanine
  • Zymosan