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Cytochemical study of granulation tissue in zinc treated rats.

The effect of zinc administration on cell composition of early granulation tissue has been studied in rats using histological and cytochemical methods. Granulation tissue was obtained by subcutaneous implantation of polyvinyl sponges. The experimental group was given zinc intramuscularly daily beginning preoperatively. Zinc administration does not change the early inflammatory cell infiltration but results in a more rapid disappearance of polymorphonuclear granulocytes from the granulation tissue. No effect can be seen on the mononuclear cell population. The observations are related to alterations in repair processes following zinc administration.

Acid Phosphatase↗

Growth hormone stimulates granulation tissue formation and insulin-like growth factor-I gene expression in wound chambers in the rat.

It has been reported that GH stimulates fibroblast growth and wound healing. In the present study we measured the effect of locally applied GH on insulin-like growth factor (IGF-I) mRNA concentrations and granulation tissue formation in wound cylinders, implanted s.c. Four stainless-steel wiremesh cylinders were implanted s.c. in the back of male rats (280 g). Each cylinder was then injected every day with either 0.014 or 0.14 U human GH, or vehicle only. Ingrown granulation tissue and wound fluid was obtained on day 17 after implantation. The wet weight of granulation tissue was determined and concentrations of IGF-I mRNA in the tissue were measured by solution hybridization/RNAase protection assay. Similar assays were used to measure the levels of IGF-I receptor mRNA and GH receptor mRNA, while the IGF-I concentration in wound fluid and serum was determined by radioimmunoassay (RIA) after acid-ethanol extraction. The concentrations of IGF-I mRNA in ingrown granulation tissue as well as the wet weight of this tissue were significantly higher in the GH-treated cylinders. There was no significant effect of GH on IGF-I receptor mRNA and GH receptor mRNA levels. Consistent with the results of previous studies, wound fluid IGF-I levels were lower than serum IGF-I levels, but no significant difference was found between the GH-treated cylinders and the control cylinders. The results of the present study show that GH stimulates granulation tissue formation and increases the concentration of IGF-I mRNA in the ingrown granulation tissue.

Animals↗

Type V collagen in experimental granulation tissue.

To evaluate the spatial and temporal expression of type V collagen in a wound healing model, subcutaneously implanted viscose cellulose sponges in rats were used to induce granulation tissue formation. Analyses on granulation tissue were carried out on days 3, 5, 8, 14, 21, 30, 59 and 84. Acid soluble collagens were extracted and the relative amount of type V collagen was quantified by SDS-PAGE. Specific antibodies to type I, III and V collagens were used in immunohistochemistry and specific RNA probes to proalpha1(I), proalpha1(III) and proalpha1(V) collagen in in situ hybridization. Type V collagen content increased relative to type I and III collagens up to day 8 and remained at the same level for up to the three months. Type V collagen was expressed strongly in blood vessel walls as seen in immunohistochemistry. In situ hybridization showed that all of the three types of collagen were expressed mostly in fibroblast-like cells and also in rounded cells, especially type V collagen. In conclusion, type V collagen was seen in the wound healing model in increasing amounts from day 3 onwards, its localization being highly associated with blood vessels in granulation tissue and it was synthesized by fibroblast-like and rounded cells.

Animals↗

Isolation and characterization of type V collagen from human post-burn granulation tissues.

Sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis of pepsin-solubilized collagens from post-burn granulation tissues revealed that type V collagen consisted of 3 alpha chains: alpha 1(V), alpha 2(V), and alpha 3(V). The mean value (0.12 +/- 0.01 SD) of the type V/type I ratio in the granulation tissues was significantly higher (p less than 0.001) than that (0.03 +/- 0.01 SD) of the ratio in normal skin. The average ratio of alpha 1(V):alpha 2(V):alpha 3(V) of type V collagen purified from the granulation tissues was determined to be about 5:3:1. SDS-polyacrylamide gel electrophoresis patterns of 3 alpha chains were not affected in the presence or absence of 2-mercaptoethanol. Purified type V collagen was degraded by bacterial collagenase, but remained intact after tadpole collagenase digestion, in contrast to type I and type III collagens. Amino acid analyses of each alpha chain separated on SDS-gel electrophoresis of type V collagen revealed that all 3 alpha chains of type V collagen were poor in alanine, rich in hydroxylysine, and had high ratios of hydroxylysine/lysine, which are typical features of type V collagen. The purified type V collagen was further fractionated by ammonium sulfate into 2 molecular species, [alpha 1(V)]2 alpha 2(V) and alpha 1(V)alpha 2(V)alpha 3(V). Our data demonstrate that type V collagen in preparations from human post-burn granulation tissues consists of 3 alpha chains and can be resolved into 2 distinct heterotrimers.

Amino Acids↗

Presence of IFN-gamma and IL-4 in human periapical granulation tissues and regeneration tissues.

To study mediators associated with the progression of disease and the process of bone regeneration in human apical periodontitis, we examined samples of periapical granulation tissues and regeneration tissues obtained from five patients by use of immunohistochemical methods. Periapical granulation tissues were found to contain a large number of CD4-positive T cells and CD68-positive monocytes/macrophages (CD4: 35.2%, CD68: 32.7%). The CD4-positive T cells and CD68-positive monocytes/macrophages were predominantly present in regeneration tissues (CD4: 62.1%, CD68: 16.0%). In these the percentages of CD4-positive T cells were higher as compared with periapical granulation tissues (from 35.2% to 62.1%). In periapical granulation tissues, CD4-positive T cells stained positively for interferon-gamma (IFN-gamma) and negatively for interleukin-4 (IL-4). In regeneration tissues, IL-4-producing cells could be detected. However, IFN-gamma-producing cells could not be detected. These results suggest that IFN-gamma and IL-4 may modulate the pathogenesis of infectious disease and the process of bone regeneration in local inflammation sites such as human apical periodontitis.

Adolescent↗

Effect of a hexosylceramide fraction of the hemodialysate Solcoseryl on experimental granulation tissue.

This work was carried out to study the effects of a hexosylceramide fraction (Hex-Cer) of the hemodialysate Solcoseryl on developing granulation tissue in rats. Subcutaneously implanted cylindrical hollow viscose-cellulose sponges were used as an inductive matrix for the growth of granulation tissue. In the control animals, the implants were treated daily by withdrawing 1 ml of wound fluid from the central dead space of the implant and by injecting back 1 ml of physiological saline. In the experimental animals, the aspirated wound fluid was replaced by a corresponding volume of a solution containing 0.08 microgram of Hex-Cer in physiological saline. Analyses of the wound fluid and granulation tissue were carried out 4, 10 and 21 days after the implantation. Statistically significant increases in the mean amounts of granulation tissue DNA and RNA were observed in the Hex-Cer group as compared with the controls, indicating an augmented cellularity. Concurrently, the mean amounts of collagen hydroxyproline in the Hex-Cer group were significantly higher than the respective control values. Similarly, on days 4 and 10, the amounts of uronic acids were higher in the Hex-Cer group than in the controls, reflecting an enhanced accumulation of glycosaminoglycans. The tissue hemoglobin reflecting the degree of vascularization rose gradually as the healing progressed, the mean amounts being generally higher in the Hex-Cer group than in the controls. Wound fluid pO2, pCO2 and pH as well as wound fluid hemoglobin and lactate concentrations showed no essential differences between the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Actihaemyl↗

The effect of 2,5-hexanedione on newly formed collagen in granulation tissue.

The mechanical strength of newly formed collagen in granulation tissue was investigated by implantation of cellulose sponges into rats intoxicated with 2,5-hexanedione (2,5-HD) and control rats. Intoxication with 2,5-HD caused a significant decrease in mechanical strength after 20 days of implantation. No differences were found between 2,5-HD intoxicated and control groups in the amount of collagen formed in the sponges. The mechanical strength of granulation tissue depends on formation and cross-linking of the newly formed collagen fibrils. 2,5-HD is known to react with epsilon-amino groups of lysine and it is therefore able to interfere with both fibril aggregation and cross-linking of the collagen. On the other hand, 2,5-HD induces the formation of cross-links in intact tendon collagen. Therefore, we stress that it is essential to distinguish between intact and newly formed fibrils when evaluating the effect of 2,5-HD on fibillary proteins.

Animals↗

Plasma membranes from experimental granulation tissue.

1. A procedure was developed for the preparation of plasma membranes from experimental granulation tissue of the rat without the addition of enzymes. The yield is better than 20% and the purification at least tenfold. 2. Values are given for the activities of 5'-nucleotidase, Na-+, k-+-activated Mg-2+dependent adenosine triphosphatase and leucine beta-naphthylamidase, for lipid composition, and for the gel-electrophoretic patterns of proteins and glycoporteins in the membrane preparations. 3. The plasma membranes from the mature granulation tissue contain proportionally more protein in the lipid phase, but the specific activities of 5'-nucleotidase and Na-+,K-+-activated Mg-2+-dependent adenosine triphosphatase are smaller than in the proliferating tissue. Certain differences were repeatedly observed in the gel-electrophoretic patterns of the developmental phases. 4. The plasma membranes from the granulation tissue were compared with those from rat peritoneal macrophages and from embryonic-chick tendon cells.

Adenosine Triphosphatases↗

Proliferation activity and apoptosis in granulation tissue and cholesteatoma in middle ear reoperations.

The aim of the study was to find out the potential prognostic value of proliferation activity and apoptosis in cholesteatoma and granulation tissue removed during middle ear reoperation in recurrent middle ear inflammation. Granulation tissues and recurrent cholesteatoma were analysed after being surgically removed from the middle ear in a group of 25 patients qualified for middle ear reoperation procedure. Paraffin sections were stained with haematoxylin and eosin according to Mallory's method. Immunohistochemical reaction Anti-PCNA was performed. Apoptosis was evaluated using the TUNEL method. The percentage of PCNA-positive cells was 42-95% in the matrix of the cholesteatoma and 29-81% in the perimatrix. In the granulation tissue it was 35-75%. The percentage of apoptotic cells was 12-73% in the matrix of the cholesteatoma, 5-72% in the perimatrix and 1-65 % in the granulation tissue. The prognostic value of the parameters studied in the recurrent middle ear inflammatory process is questionable, probably due to the small number of cases under examination.

Adult↗

Osseous drill holes to promote granulation tissue: radiologic appearance.

Skin grafting following extensive soft-tissue loss is often delayed until adequate granulation tissue can be generated. Surgical drill holes into the marrow cavity promote development of granulation tissue. This article illustrates the radiology appearance of these drill holes in four patients.

Adult↗

Effect of epidermal growth factor (EGF) on experimental granulation tissue.

Subcutaneously implanted cylindrical hollow viscose cellulose sponges were used to study the effects of locally applied epidermal growth factor (EGF) on developing granulation tissue in rats. In the first set of experiments the test implants were treated with a single injection of a solution containing 5 micrograms of EGF in 0.5% albumin while the control implants were treated correspondingly with the carrier solution only. In the second set of experiments the injections of both test and control implants were repeated daily. Analyses of wound fluid and granulation tissue in the sponge cylinders were carried out 10 days after implantation. After single application of EGF no essential differences were detected in wound fluid prostaglandin E2 levels or various components of granulation tissue between the groups. After daily application, however, a stimulatory effect of EGF on granulation tissue formation was observed: cellularity increased, as evidenced by the elevated amounts of nucleic acids, and accumulation of collagen and glycosaminoglycans was enhanced.

Animals↗

Calcitonin and granulation tissue formation in the rat. An experimental study.

The effects of systemically administered calcitonin (CT) on granulation tissue development were compared using viscose cellulose sponges as wound model in the rat. The ingrowth of new granulation tissue was analyzed for the contents of various connective tissue components (total nitrogen, hydroxyproline, DNA, and RNA) and for the differential counts of the cells infiltrating the sponges. The results indicate that up to 4 weeks postoperatively (p.o.) CT did not affect the net amount of collagen, measured as hydroxyproline, total nitrogen, aminosugars nor the dynamics of differentiation and viability of the invading cells. The present observation that CT has negligible effects, if any, on the early stages of connective tissue formation and on the cell population indicates that surgical procedures could be carried out safely during systemic CT therapy without an increased risk of wound complications.

Animals↗

GM-CSF-induced granulation tissue formation: relationships between macrophage and myofibroblast accumulation.

We have studied the formation of granulation tissue around osmotic minipumps delivering granulocyte macrophage-colony stimulating factor (GM-CSF) chronologically in the rat using electron microscopy and immunohistochemistry at the light and electron microscopic levels, with specific antibodies against alpha-smooth muscle (SM) actin and rat macrophages. At 2 and 3 days after pump implantation, GM-CSF application produced an extensive inflammatory reaction characterized by edema and the accumulation of polymorphonuclear cells and macrophages. Gradually, polymorphonuclear cells decreased in number and macrophages became arranged in large clusters. The expression of alpha-SM actin in fibroblastic cells of the granulation tissue started from the 4th day after pump implantation and progressed up to the 7th day. Double immunofluorescence staining showed macrophage clusters in relation to alpha-SM actin-rich fibroblastic cells. Electron microscopic examination confirmed that the fibroblasts containing alpha-SM actin-positive stress fibers were found initially in close proximity to clustered macrophages. The delivery of platelet-derived growth factor (PDGF) and tumor necrosis factor-alpha (TNF-alpha) by the osmotic minipump induced an accumulation of macrophages, but in a much smaller number compared with those seen after GM-CSF application; these macrophages were never assembled in clusters and, furthermore, TNF-alpha and PDGF did not stimulate alpha-SM actin expression in fibroblastic cells. Our results suggest that after GM-CSF administration, the cluster-like accumulation of macrophages plays an important role in stimulating alpha-SM actin expression in myofibroblasts. Our results may be relevant to the understanding of the processes leading to granulation tissue formation in this and other experimental models.

Actins↗

Fibroepithelial polyps of the vagina: are they old granulation tissue polyps?

AIMS: To study the nature of fibroepithelial polyps of the vagina. METHODS: Sixty five fibroepithelial polyps of the vagina and 64 granulation tissue polyps diagnosed over 15 years were reviewed histologically. RESULTS: Cytologically benign multinucleated stromal cells were present in large numbers in 19 of the fibroepithelial polyps of the vagina (FEPV). Only one polyp contained atypical stromal cells, a high mitotic count, and abnormal mitoses and was indistinguishable from a malignant tumour. Immunostaining showed the presence of vimentin and desmin positive mono- and multinucleated stromal cells in FEPV and occasional oestrogen receptor positive nuclei. Desmin positive cells could not be shown in granulation tissue polyps. CONCLUSIONS: FEPV are common lesions with benign mono- and multinucleated fibroblastic stromal cells in which myoid differentiation is often present. FEPV may develop as a result of a granulation tissue reaction after some local injury of the vaginal mucosa. Hormonal factors may modulate the growth of FEPVs. Delayed differentiation of myofibroblastic cells may explain why granulation tissue sometimes does not contract properly but turns into polyps.

Adolescent↗

Myofibroblasts in cotton-induced granulation tissue and the bovine adrenal capsule: morphological aspects.

Ultrastructural studies of one week old cotton-induced granulation tissue revealed the presence of polymorphonuclear neutrophils (PMN), macrophages and mast cells, whilst the granulation tissue from two week old cotton implants contained fibroblasts, myofibroblasts and abundant collagen fibres. Similarly, the bovine adrenal capsule contained both fibroblasts and myofibroblasts. It is proposed that the bovine adrenal capsule and two week cotton-induced granulation tissue could be utilized as in-vitro models to study the mechanism(s) involved in myofibroblast contraction.

Adrenal Glands↗

[Regulative effects and significance of substance P on the expression of basic fibroblast growth factor of granulation tissue fibroblasts in vitro].

OBJECTIVE: To explore the regulative effects and significance of neuropeptide substance P (SP) on the expression of basic fibroblast growth factor (bFGF) of granulation tissue fibroblasts in vitro. METHODS: A local aseptic inflammation was induced by injection of formaldehyde in rats, and its granulation tissue was cultured. RT-PCR was employed to observe expression of bFGF mRNA after inducement of SP at different concentrations and time points in the granulation tissue, and western blot to assay expression of bFGF protein. RESULTS: The expression of bFGF mRNA was markedly increased significantly 3 and 6 hours after inducement with SP in 10(-7) mol/L, compared with control group (P < 0.01). The expression of bFGF protein was markedly higher than the control group after 12 hours, and it reached the peak at the 24th hour and declined gradually after 48 hours. SP at concentrations of 10(-9) - 10(-5) mol/L could significantly promote the expression of bFGF mRNA, and that at 10(-8) - 10(-5) mol/L induce the expression of bFGF protein. Both expressions reached the peak when SP concentration was 10(-7) mol/L (P < 0.01). CONCLUSION: SP can induce the expressions of bFGF mRNA and bFGF protein of granulation tissue fibroblasts in vitro, which may possess an important significance in wound healing.

Animals↗

Basement membrane-type heparan sulfate proteoglycan (perlecan) and low-density lipoprotein (LDL) are co-localized in granulation tissues: a possible pathogenesis of cholesterol granulomas in jaw cysts.

BACKGROUND: As perlecan contains a low-density lipoprotein (LDL) receptor-like repeats in the second domain of its core protein, LDL may be bound to perlecan, which is rich in granulation tissues. We wanted to study if this is the case in the cyst wall of radicular cysts, which are often associated with cholesterol granuloma. METHODS: Thirty-three specimens of radicular cyst with cholesterol granulomas were immunohistochemically examined for comparative localizations of perlecan, apoprotein B (apo B), and oxidized LDL (Ox-LDL), and for mRNA expression levels for perlecan. RESULTS: Myxoid or edematous stroma of immature granulation tissues was strongly positive for perlecan and simultaneously for apo B and Ox-LDL. Macrophages including foamy cells scattered in the granulation tissues were also immunopositive for Ox-LDL and occasionally for apo B. In situ hybridization showed that fibroblasts, endothelial cells, and pericytes had strong signals for perlecan, which was also confirmed by RT-PCR. CONCLUSION: These results suggest that perlecan, which is abundantly produced and accumulated in the cyst wall of immature granulation tissue, traps Ox-LDL locally, and that Ox-LDL is phagocytosed by macrophages. Thus, LDL-laden foamy macrophages are aggregated in the granulation tissue, and free cholesterol from ruptured macrophages may be concentrated locally to be crystallized, which may induce foreign body granulomas in the cyst wall.

Animals↗

Are excessive granulation tissue formation and retarded wound contraction due to decreased collagenase activity in wounds in tight-skin mice?

Wound contraction is delayed in tight-skin mice but the mechanism(s) are unknown. The purpose of this study was to investigate collagenase levels and the formation of granulation tissue in experimental wounds in tight-skin mice. One full-thickness skin excision (20 x 20 mm) was made on the back of nine tight-skin and eight normal mice. Granulation tissue analyses were performed 7 days post-operatively. The collagenase activity was determined by the use of a radiolabelled telopeptide-free collagen substrate, and the amount of granulation tissue was determined gravimetrically. Wound contraction was delayed (P < 0.001) in tight-skin mice (mean 22%) compared with normal mice (mean 46%). The collagenase activity was decreased (P < 0.05) by 40%, whereas the quantity of granulation tissue was increased (P < 0.001) by 60% in the wounds of tight-skin mice. Decreased collagenase content may provide one explanation for the delayed contraction of full-thickness wounds in tight-skin mice. Furthermore, this animal would model may prove useful in the understanding of the pathogenesis, and in exploration of treatment, of excessive granulation tissue formation during wound healing.

Animals↗