title: Origin of myofibroblasts in the avascular capsule around free-floating intraperitoneal blood clots.
abstract: The origin of cells comprising the capsule which forms around free-floating intraperitoneal blood clots has been examined in rats. One day after implantation the surface of the clot was covered by 1-2 layers of rounded nucleated cells. The majority of these cells were monocyte/macrophage in type with many cytoplasmic folds. Over the next 2 wk a thick capsule composed of dense connective tissue and myofibroblasts developed, completely covering the clot. The surface became covered by a contiguous layer of mesothelial cells, apparently derived from displaced cells of the damaged peritoneum. Detailed examination of the formation of the capsule suggested that a proportion of cells with the characteristic features of peritoneal macrophages gradually develop over a 3-4 d period the characteristic features of fibroblasts. These cells with time then develop filament bundles and a basal lamina to become myofibroblasts.
mesh_terms: D000818:Animals; D001777:Blood Coagulation; D005347:Fibroblasts / Q000166:cytology*; D006097:Granulation Tissue / Q000166:cytology; D008264:Macrophages / Q000166:cytology; D009130:Muscle, Smooth / Q000166:cytology*; D010537:Peritoneum; D051381:Rats; D013997:Time Factors