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Interaction of mesothelium to intraperitoneal stimulation. I. Aggregation of peritoneal cells
Abstract:
The effect of intraperitoneal injections of bacterial toxin and adjuvant on the diaphragmatic mesothelium and their interaction with peritoneal cells was investigated in mice. At 30 minutes to 8 hours after stimulation, large numbers of neutrophils were seen on the mesothelial surface. Many of these cells exhibited features characteristic of locomotion over the mesothelial surface, whereas others appeared to be in the process of entering and passing through stomata into lymphatic vessels. By 24 hours numerous neutrophils, macrophages, and a small number of lymphocytes formed cellular aggregates that were surrounded by fibrin filaments. At 48 hours, the peritoneal cells were more closely aggregated and formed several layers on the mesothelial surface. By 72 hours fibrin filaments appeared to be broken down in many areas, with a resultant electron-dense precipitate occupying large areas of the intercellular spaces and on the surfaces of cells. It is suggested that the fibrin provides a matrix for the adhesion and subsequent aggregation of peritoneal cells to the mesothelial surface. The separation of neighboring mesothelial cells which surrounded stomata caused a widening of mesothelial pores (stomata), thereby facilitating the egress of the increased fluid and cellular infiltrations caused by the stimulation. The presence of patent stomata underlying the cellular aggregate demonstrates the importance of the diaphragmatic stomata as a major passageway for the removal of fluids and cells in the unstimulated, as well as during the inflammatory, response.
Insights
Bacterial toxins trigger neutrophil migration and aggregation on the diaphragm's mesothelium. This process, involving stomata widening, facilitates fluid and cell removal during inflammation.
Area of Science:
- Immunology
- Cell Biology
- Histology
Background:
- The peritoneal mesothelium acts as a barrier and plays a role in immune surveillance.
- Understanding mesothelial cell and peritoneal cell interactions is crucial for inflammatory response research.
Purpose of the Study:
- To investigate the dynamic effects of bacterial toxin and adjuvant on the diaphragmatic mesothelium and peritoneal cells.
- To elucidate the role of mesothelial stomata in inflammatory cell and fluid transport.
Main Methods:
- Intraperitoneal injections of bacterial toxin and adjuvant in mice.
- Microscopic examination of diaphragmatic mesothelium and peritoneal cells at various time points (30 minutes to 72 hours).
- Analysis of cellular morphology, adhesion, aggregation, and transport through stomata.
Main Results:
- Neutrophils rapidly adhered to the mesothelium, exhibiting locomotion and trans-stomal migration.
- Fibrin formation supported neutrophil and macrophage aggregation by 24 hours, with layered cell structures by 48 hours.
- Mesothelial cell separation widened stomata, facilitating fluid and cellular egress, with patent stomata observed throughout the inflammatory response.
Conclusions:
- Fibrin acts as a matrix for peritoneal cell adhesion and aggregation on the mesothelium.
- Diaphragmatic stomata are critical passageways for fluid and cell removal during both basal and inflammatory conditions.
- Mesothelial cell dynamics and stomatal function are key components of the peritoneal inflammatory response.