Identification of macrophages at the site of peritoneal injury: evidence supporting a direct role for peritoneal macrophages in healing injured peritoneum  A.F Haney, M.D.  Fertility and Sterility  Volume 73, Issue 5, Pages 988-995 (May 2000) DOI: 10.1016/S0015-0282(00)00490-8

FIGURE 1 Transmission electron micrographs of cytospin preparations of peritoneal fluid 24 hours after injection of vehicle only. (A), The predominant cell type has the characteristic appearance of a mononuclear phagocyte, e.g., a macrophage, with a large nucleus, an irregular shape, and cytoplasmic phagolysosomes. There are occasional polymorphonuclear leukocytes and eosinophils, typical of the peritoneal fluid of mice (original magnification, ×3,000). (B), When polystyrene beads were injected, the peritoneal fluid contained both free beads and macrophages with internalized beads. The macrophages with internalized beads are enlarged by displaced nuclei with fragile plasma membranes, making them susceptible to breakage upon centrifugation (original magnification, ×2,000). Haney. Peritoneal macrophages. Fertil Steril 2000. Fertility and Sterility 2000 73, 988-995DOI: (10.1016/S0015-0282(00)00490-8)

FIGURE 2 Transmission electron micrographs of the full thickness of the peritoneum. (A), When the animals had polystyrene beads injected 24 hours before death, no beads were noted in the peritoneal layer. The surface has the typical morphology of the peritoneum, with a confluent mesothelial layer characterized by microvilli extending into the peritoneal cavity, dense junctions between mesothelial cells, and an underlying large extracellular matrix layer overlying smooth muscle (original magnification, ×5,000). (B), When the animals had polystyrene beads injected 14 days earlier and the peritoneal fluid removed 7 days before death, the morphology of the peritoneal surface was unchanged, with the exception of a small amount of edema and a subjectively increased number of cells within the extracellular matrix layer (original magnification, ×2,000). Haney. Peritoneal macrophages. Fertil Steril 2000. Fertility and Sterility 2000 73, 988-995DOI: (10.1016/S0015-0282(00)00490-8)

FIGURE 3 Transmission electron micrographs of the surface of the peritoneum after injury, without polystyrene beads injected. (A) Twenty-four hours after injury there are large round cells adherent to the wound surface, which have the typical morphology of macrophages with microplicae and phagolysosomes. Despite the contact between cells and the extracellular matrix, there is a notable absence of tight junctions between the cells, which is characteristic of mesothelial cells (original magnification, ×2,500). (B), By 3 days after injury, the cells on the surface with the morphology of macrophages are being displaced downward by cells with the flattened morphology characteristic of mesothelial cells, which are reconstituting the mesothelial layer enclosing the peritoneal macrophages below the surface (original magnification, ×4,000). Haney. Peritoneal macrophages. Fertil Steril 2000. Fertility and Sterility 2000 73, 988-995DOI: (10.1016/S0015-0282(00)00490-8)

FIGURE 4 Transmission electron micrographs of the surface of the peritoneum after injury, with polystyrene beads injected. (A), Twenty-four hours after injury there are peritoneal macrophages (as evidenced by ingested beads) adherent to the wound surface. Note the absence of mesothelial cells (original magnification, ×4,000). (B), By 3 days after injury, peritoneal macrophages are being displaced downward as they are covered by mesothelial cells, which are reconstituting the surface enclosing the peritoneal macrophages below the surface (original magnification, ×6,000). Haney. Peritoneal macrophages. Fertil Steril 2000. Fertility and Sterility 2000 73, 988-995DOI: (10.1016/S0015-0282(00)00490-8)

FIGURE 5 Transmission electron micrograph of a peritoneal wound 7 days after injury, with polystyrene beads injected. The peritoneal surface has been reconstituted with a confluent layer of flattened mesothelial cells lacking internalized beads, characterized by microvilli protruding into the peritoneal cavity and tight junctions between the confluent mesothelial cells. There are peritoneal macrophages, as evidenced by ingested beads, scattered throughout the area of the healing wound below the intact surface mesothelium (original magnification, ×3,000). Haney. Peritoneal macrophages. Fertil Steril 2000. Fertility and Sterility 2000 73, 988-995DOI: (10.1016/S0015-0282(00)00490-8)

FIGURE 6 Transmission electron micrograph of the deep layer of a healing peritoneal wound 7 days after injury, with polystyrene beads injected. Note the large number of peritoneal macrophages containing beads within the submesothelial layer (original magnification, ×3,000). In most areas, the peritoneal macrophages were virtually confluent. Haney. Peritoneal macrophages. Fertil Steril 2000. Fertility and Sterility 2000 73, 988-995DOI: (10.1016/S0015-0282(00)00490-8)