Contraction of Granulation Tissue in vitro: Similarity to Smooth Muscle

Abstract

Strips of granulation tissue from three different experimental models contract in vitro when treated with substances that induce contraction of smooth muscle. Because the fibroblasts in such tissues have some ultrastructural features typical of smooth muscle, our findings indicate that fibroblasts are able to modulate toward a cell type that is morphologically and functionally close to smooth muscle.

Mechanism by Which Indomethacin Delays Gastric Ulcer Healing in the Rat: Inhibited Contraction of the Ulcer Base

“…As expected, the tissue isolated from the ulcer base in the control group was contracted by serotonin, brady kinin and carbachol, and was also slightly contracted by PGF1a, confirming the observation of Majno et al (11,12) as to wound healing. To our knowledge, this is the first demonstration that the ulcer base has the ability to contract in response to certain agents.…”

“…Majno et al (11,12) were the first to demonstrate in in vitro experiments that the granulation tissue isolated from a dermal wound exhibits the ability to contract in response to serotonin, bradykinin and PGF,a. They sug gested that this contractile force, which is probably due to myofibroblasts, may participate in the early stages of wound healing.…”

Time-dependent appearance of myofibroblasts in granulation tissue of human skin wounds

“…A p a r t from the usual matrixsynthesizing "resting" fibroblast, a specialized subtype of fibroblastic cells with contractile properties, the socalled myofibroblasts, has been identified in healing wounds. These myofibroblasts show some features intermediate between fibroblasts and smooth muscle cells as demonstrated by immunohistochemical and electron microscopical studies and they are presumed to be involved in w o u n d contraction [8,11,19].…”

Promotion of Growth of Tumour Cells in Acutely Inflamed Tissues

“…The final concentration (10-4 g per ml) of the mediators present in the-incubation medium greatly exceeded the local tissue concentrations required to induce inflammatory oedema in rats, and the maximum doses tolerated by rats (measured as dose per unit body weight) when the drugs were administered parenterally. The mediators tested in vitro on sensitive preparations of contractile rat and guineapig tissues (including granulation tissue) induced maximum contractile responses at a concentration of less than 10-4 g per ml in the test bath (unpublished data; Gaddum, 1949;Majno et al, 1971). …”