GRANULYATSIONNY FABRIC (Latin granulum kernel; synonym: granulation, «wild meat», granular fabric) — the connecting fabric which is formed during the healing of fabric defects by second intention.
Originally this term was used only for the characteristic of the wound processes proceeding in the fabrics possessing a free surface (skin, a mucous membrane) and therefore seen by an eye. But it is lawful also in relation to young connecting fabric (see), forming at the organization of blood clots, heart attacks, inflammatory exudates and encapsulation of foreign bodys. G.'s formation t. — manifestation of one of three consistently replacing each other of stages of a wound process — inflammations (see), formations of granulations, scarrings. Directly behind damage traumatic hypostasis develops, in process to-rogo there is excess fluid accumulation in the damaged fabrics. Edematous liquid contains a large amount of proteins: albumine, globulins, fibrinogen. The inflammatory reaction replacing traumatic hypostasis leads to fusion of dead fabrics and clarification of a wound. Even before completion of this process in day and at the edges of a wound G. of t begins to develop. (tsvetn. fig. 12, a), gradually filling the arisen defect. G.'s development by t. represents manifestation regenerations (see). Complex structure of G. of t. H is in detail described. N. Anichkov, K. G. Volkova, V. G. Garshin (1951). Its surface is covered with the necrotic masses (tsvetn. fig. 12, b) containing a fine-grained detritis, fibrin, a large number of leukocytes and erythrocytes. Under this leukocytic and necrotic layer the layer of vascular loops containing thin-walled vessels, polymorphonuclear leukocytes and fibroblasts is located. Intensive proliferation of endotheliocytes provides rapid growth of the capillaries which are reaching a wound surface and then, forming loops, again going to depth of fabric. Tops of loops from a surface have an appearance of reddish grains owing to what young connecting fabric and received the name granulyatsionny, granular. Under a layer of vascular loops the layer actually of G. of t lies., or the layer of vertical vessels making its main weight. Between vertically located vessels of this layer there is an amorphous interstitial (main) substance representing gelatinous weight. Even more deeply the layer of horizontally located fibroblasts — the ripening layer lies. This layer, being gradually thickened, plays the main role at a wound repair. Morfol, his feature is various cellular structure: there are fibroblasts, eosinophilic granulocytes, macrophages, mast cells. Deep sites of this layer gradually I take * a form of the fibrous fabric making a bottom, and it is frequent also edges of a wound.
At early stages of development of G. of t. consists preferential of the amorphous interstitial substance containing acid mucopolysaccharides (hyaluronic to - that, chondroitinsulphuric to - that, a glycosamine, a galactose - min., heparin); in it not numerous connective tissue cells and fibroblasts, histiocytes, mast cells, neutrophilic and eosinophilic granulocytes, cells of a lymphoid row, or polyblasts are disseminated. The acid mucopolysaccharides which are synthesized fibroblasts and mast cells are a part of collagenic bunches as the material cementing collagenic fibrilla. General dynamics of development of G. of t. consists in gradual reduction of amount of amorphous substance, intensive proliferation of cellular elements and vessels which number further, in process of increase of mass of collagenic fibers and formation of a hem, decreases. Leading role in formation of the main substance G. of t. and especially its fibrous structures play fibroblasts. These cells, in usual conditions thin, extended, with a small narrow kernel and the cytoplasm poor in ultrastructures, at activation of biosynthetic processes become large, with a big ovoidny kernel and sharply increased volume of cytoplasm. At a submicroscopy in such fibroblasts observe increase in number of mitochondrions, a hypertrophy of a lamellar complex (see. Golgi complex ) and expansion of its tanks, considerable hyperplasia of a rough endoplasmic reticulum responsible for synthesis of collagenic proteins (fig. 1). Fibroblasts have high activity hydrolytic (acid and alkaline phosphatases) and proteolytic (aminopeptidase, cathepsines) enzymes. Activity of oxidation-reduction enzymes is less expressed in fibroblasts (succinatedehydrogenases, cytochrome oxydases, etc.). Their cytoplasm contains a large number of a glycogen and ribonucleoproteins. The autoradio graphic research demonstrates intensive synthesis of RNA in G.'s fibroblasts of t. (fig. 2). Concerning an origin of fibroblasts of G. of t. there are various points of view. One researchers consider more probable their local origin from adventitious cells, others believe that fibroblasts get to G. of t. in the hematogenous way; there is also an opinion allowing existence of both of these sources. The signs of high biosynthetic activity noted at fibroblasts equally are observed also in other cells of G. of t. — corpulent, macrophages, endotheliocytes. Mast cells take part in formation of interstitial substance of connecting fabric. Believe that, on the other hand, they regulate composition of intercellular substance, absorbing excess of the mucopolysaccharides which are laid in their cytoplasm in the form of granules. Emergence and activation of mast cells is almost exclusive in the ripening layer of granulations, in Krom there is a constant decrease of acid mucopolysaccharides, do this assumption quite reasonable. Degrowth of amorphous substance in the ripening G. of t. happens synchronously to increase in the number of fibrous structures in it. About the fibroblasts lying lengthways vertically located vessels gentle collagenic fibers appear. In the same time in G. of t. find in a large number and argyrophil fibers. High activity of enzyme of a collagenase in cytoplasm of fibroblasts demonstrates that these cells, apparently, provide not only synthesis of collagenic fibers, but also their partial lysis thanks to what regulation of quantity of new growths of fibrous fabric is reached. At early stages of a new growth of G. of t. processes of a rassasyvaniye are expressed poorly. Intensive they become during maturing of granulations when there is an increase of mass of collagenic fibers which part is exposed to a rassasyvaniye. During the closing of wound defect and formation of a hem process of a rassasyvaniye of collagenic fibers abates. In process of G.'s maturing t. the amount of interstitial amorphous substance, mast cells, histiocytes, leukocytes and other its cellular elements decreases, and the amount of the growing coarse collagenic fibers increases. In development of a hem also biosynthetic activity of fibroblasts which turn into the «based» fibrocytes gradually abates. During this period euzymatic activity of fibroblasts decreases, in their cytoplasm the maintenance of a glycogen and RNA (fig. 3) decreases, the number of cytoplasmatic structures decreases. In the final of a wound process the cicatricial fabric representing bunches of coarse collagenic fibers with not numerous fibrocytes and vessels located between them forms. Ability of fibrocytes of cicatricial fabric to repeated active synthesis of collagen, i.e. turning into fibroblasts, is not studied. Later in a hem elastic fibers can appear.
G.'s development by t. characterizes process of a wound repair by second intention. If the wound is small and its edges are pulled most together, their accretion happens quickly, without development of considerable granulations, and in these cases speak about healing by first intention. In both cases cellular reaction and dynamics collagenose are essentially identical, and it is only about quantitative distinctions.
All development cycle and G.'s maturing t. borrows apprx. 2 — 3 weeks, however various stages of this process can drag on or proceed more intensively depending on the sizes of a wound, specific features of an organism and various conditions of the environment. At disturbances of blood circulation, an innervation, avitaminosis With various deviations from the described process of G. of t are observed. in the form of inertly current granulations, emergence of excess granulations (e.g., «wild meat» on gingivas at caries of teeth and paradentita, at long suppuration of a wound, hron, osteomyelitis) or bystry and excessive coarsening of connecting fabric with a hyalinosis of fibrous bunches and formation of so-called keloid cicatrixes. These deviations are caused by high-quality and quantitative disturbances of a kollagenoobrazovaniye in fibroblasts and surrounding their interstitial substance.
Children have a development of G. of t. proceeds more intensively, than at adults. Reduction of terms of healing of wounds is promoted also by some pharmakol, drugs, napr, pentoxyl, methyluracil, orotat potassium.
See also Wounds, wounds .
Bibliography Anichkov H. N, Volkova K. G. and Garshin V. G. Morphology of healing of wounds, M., 1951; Davydovsky I. V. Bullet wound of the person, t. 1, M., 1950; Hrushchovn. G. Problema of an origin of fibroblasts in post-natal ontogenesis of mammals, Ontogenesis, t. 5, No. 1, page 3, 1974, bibliogr.; Rae k. allio J. Enzyme histochemistry of wound healing, Progr. histochem. cyto-chem., v. 1, p. 51, 1970, bibliogr.; Repair and regeneration, ed. by J. E. Dunphy a. W. V. Winkle, p. 151, N. Y. a. o., 1969; Whitting H. The tissue mast cell and wound healing, Int. Rev. Gen. Exp. Zool., v. 4, p. 131, 1969, bibliogr.
D. S. Sarkisov.