Rat Subcutaneous Tissue Research Articles

A Mineral Trioxide Aggregate Sealer Stimulated Mineralization

The aim of this study was to evaluate the rat subcutaneous tissue response to implanted polyethylene tubes filled with Endo-CPM-Sealer (Portland Cement Modified Sealer) (EGEO S.R.L., Buenos Aires, Argentina) compared with Sealapex (SybronEndo, Glendora, CA) and Angelus MTA (Angelus, Londrina, Brazil). These materials were placed in polyethylene and dentin tubes and implanted into dorsal connective tissue of Wistar rats for 7, 15, 30, 60, and 90 days. The specimens were prepared to be stained with hematoxylin and eosin or Von Kossa or not stained for polarized light. Qualitative and quantitative evaluations of the reaction were performed. Both materials caused mild to moderate reactions at 7 days that decreased with time. The response was similar to the control on the 30th day with Endo-CPM-Sealer and Angelus MTA and on the 60th day with Sealapex. Mineralization and granulations birefringent to the polarized light were observed with all materials. It was possible to conclude that Endo-CPM-Sealer was biocompatible and stimulated mineralization.

Biological Response to Wollastonite Doped α-Tricalcium Phosphate Implants in Hard and Soft Tissues in Rats

The biological response following subcutaneous and bone implantation of β-wollastonite(β-W)-doped α-tricalcium phosphate bioceramics in rats was evaluated. Tested materials were: tricalcium phosphate (TCP), consisting of a mixture of α- and β-polymorphs; TCP doped with 5 wt. % of β-W (TCP5W), composed of α-TCP as only crystalline phase; and TCP doped with 15 wt. % of β-W (TCP15), containing crystalline α-TCP and β-W. Cylinders of 2x1 mm were implanted in tibiae and backs of adult male Rattus norvegicus, Holtzman rats. After 7, 30 and 120 days, animals were sacrificed and the tissue blocks containing the implants were excised, fixed and processed for histological examination. TCP, TCP5W and TCP15W implants were biocompatible but neither bioactive nor biodegradable in rat subcutaneous tissue. They were not osteoinductive in connective tissue either. However, in rat bone tissue β-W-doped α-TCP implants (TCP5W and TCP15W) were bioactive, biodegradable and osteoconductive. The rates of biodegradation and new bone formation observed for TCP5W and TCP15W implants in rat bone tissue were greater than for non-doped TCP.

In vivo rat subcutaneous tissue response of binder-free multi-walled carbon nanotube blocks cross-linked by de-fluorination

Binder-free multi-walled carbon nanotube (MWCNT) blocks from fluorinated MWCNTs were prepared using thermal heating and a compression method in vacuo. The resulting carbon nanotube blocks are lighter than graphite, can be machined and polished, possess average bending strengths of 102.2 MPa, a bending modulus of 15.4 GPa, and moderate wettability. The binder-free MWCNT blocks possess good biocompatibility when tested in the subcutaneous tissue of rats in vivo, which were covered by thin granulation tissue, 40–70 μm in thickness, comprising a few lymphocytes, cell with large cytoplasmic spaces like fibroblasts and foreign-body giant cells. That is indicative of a slight inflammatory response than MWCNT/resin blocks and poly(methyl methacrylate). This material can potentially be employed as an alternative artificial hard tissue or internal bone plate that makes use of the properties of CNTs.

High-resolution electron microscopy of multi-wall carbon nanotubes in the subcutaneous tissue of rats

The atomic structure of multi-wall carbon nanotubes (MWCNTs) implanted in the subcutaneous tissue of rats was examined by means of high-resolution transmission electron microscopy (HRTEM). Clusters of the MWCNTs implanted in the subcutaneous tissue were well recognized by the TEM observations. It was indicated that some nanotubes were taken in phagocytes after the 1-year implantation. The deterioration of crystalline structure of the nanotubes in phagocytes was shown by the HRTEM observation. It was suggested that the deterioration of the nanotubes was due to the peeling of the outer graphene layers in the phagocytes.

Properties of Camphorated Paramonochlorophenol and Camphorated Paramonochlorophenol Associated to Calcium Hydroxide

Objetivo: Avaliar a biocompatibilidade do paramonoclorofenol canforado na proporcao 3,5:6,5 (PMCC) e do paramonoclorofenol canforado associado ao hidroxido de calcio (PMCC+Ca(OH)2) no tecido subcutâneo de ratos, e o potencial antimicrobiano desses medicamentos frente a alguns microrganismos. Metodo: Dez ratos Wistar receberam, apos a anestesia, administracao endovenosa de corante Evan’s Blue, seguida de inoculacao de 0,1mL dos respectivos farmacos na regiao dorsal. A quantidade de corante extravasada, ligadas as proteinas do plasma foi avaliada por meio de espectrofotometria. A atividade antimicrobiana foi realizada atraves do teste de difusao em agar, (foi avaliada pela medida dos halos de inibicao) contra os microrganismos: S. aureus, S. mutans, B. subtilis e C. albicans. Resultados: Os valores medios de densidade optica para o PMCC foram de 0,325±0,025 (reacao moderada) e para o PMCC+Ca (OH)2 0,211±0,040 (discreta). Os halos de inibicao detectados foram de: PMCC – 7,29mm e PMCC+Ca(OH)2 – 7,29mm para S. aureus; PMCC – 8,57mm e PMCC+Ca(OH)2 – 7,0mm para S. mutans; PMCC – 8,57mm e PMCC+Ca(OH)2 – 7,43mm para B. subtilis e de PMCC – 8,71mm e PMCC+Ca(OH)2 – 8,29mm para C. albicans. Conclusao: Os dados obtidos indicaram que o PMCC mostrou-se mais irritante que o PMCC+Ca (OH)2, enquanto que a atividade antimicrobiana nao apresentou resultados estatisticamente diferentes (ANOVA) entre as substâncias testadas.

Assessment of the biocompatibility of Epiphany root canal sealer in rat subcutaneous tissues

The aim of this study was to evaluate the biocompatibility of the root canal sealer Epiphany in rat subcutaneous tissues. Polyethylene tubes were filled with the sealer (I: Epiphany; II: photoactivated Epiphany; III: Epiphany associated with self-etch primer; IV: photoactivated Epiphany associated with primer; and V: control group) and later implanted into 4 different regions of the dorsum of 15 adult male rats (Rattus novergicus, Albinus Wistar). After 7, 21, and 42 days, 5 animals were killed, obtaining 4 samples per group, in addition to the control group, at each analyzed time. In all periods, Epiphany induced a mild inflammatory reaction. However, in group II, in which the primer was not used, extensive necrosis and a moderate to intense inflammatory reaction were observed, mainly after 7 and 21 days. Epiphany sealer appears biocompatible when tested on rat subcutaneous tissues.

Comparison of the biocompatibility of different root canal irrigants

The purpose of this study was to compare the reaction of rat subcutaneous connective tissue to 0.9% sterile saline, 2.5% sodium hypochlorite (NaOCl), 5.25% NaOCl and 2% chlorhexidine gluconate solution or gel. Six circles were demarcated on the dorsal skin of 24 male Wistar rats, leaving 2 cm between each circle. Using a syringe, 0.1 mL of each root canal irrigant was injected subcutaneously into 5 circles. In the 6th circle, the needle of an empty syringe was introduced into the skin, but no irrigant was injected (control group). Evaluations were undertaken at 2 h, 48 h, 14 days and 30 days post-procedure. Tissue samples were excised, embedded in paraffin blocks and 3-μm-thick sections were obtained and stained with hematoxylin and eosin. The areas of inflammatory reaction were evaluated and analyzed statistically by ANOVA and Tukey's test. The control group showed few or no inflammatory reaction areas in the subcutaneous tissue. 0.9% saline solution, 2.0% chlorhexidine solution and 2.5% NaOCl showed a good biocompatibility, as very mild inflammatory reaction was detected at 14 days and tissue repair occurred at 30 days. 5.25% NaOCl was the most toxic irrigant, as the number of inflammatory cells remained elevated at 14 and 30 days. The group treated with 2.0% chlorhexidine gluconate gel presented a moderate inflammatory response at 14 days, which decreased at 30 days, being considered similar to that of the control group, 0.9% saline solution, 2.0% chlorhexidine solution and 2.5% NaOCl at this experimental period.

Expression of lymphatic vessel endothelial hyaluronan receptor‐1 (LYVE‐1) on macrophages in rat subcutaneous connective tissue

Lymphatic vessel endothelial hyaluronan receptor‐1 (LYVE‐1) was thought to be expressed exclusively on the lymphatic endothelium Recent evidence also suggests expression of LYVE‐1 on some monocytes and macrophages in malignant tumors, inflamed cornea and in wound healing tissue. To date, there are not any reports about the expression of LYVE‐1 on subcutaneous connective tissue cells. The goal of this study was to examine LYVE‐1 expression in normal connective tissue of the rats and determine phenotype of LYVE‐1+ cells by using an immunohistochemistry. Staining of thick sections of rat skin with anti‐LYVE‐1 clearly revealed both lymphatic vessels in dermal layer and a large population of LYVE‐1+ nonvascular cells in subcutaneous connective tissue. Phenotype analysis showed that LYVE‐1+ cells uniformly expressed CD45, F4/80 and CD11b, but not CD11c, CD3 and HIS48 indicating these cells to be tissue macrophages. Immunoelectron microscopy also confirmed that LYVE‐1+ cells are macrophages, and that abundant expression of LYVE‐1 was predominantly observed on the microvilli. LYVE‐1+ macrophages were distributed as single cells but some of them formed tight cell contact with each other as well as cord‐ and tubular‐like structures. Taken together, these results demonstrate, for first time, that tissue macrophages express LYVE‐1 and can form cord‐ and tubular like structures in normal subcutaneous connective tissue, implicating that LYVE‐1+ macrophages may be involved in the formation of subcutaneous lymphatic vessels in rats.

PIKfyve Negatively Regulates Exocytosis in Neurosecretory Cells

Regulated secretion depends upon a highly coordinated series of protein-protein and protein-lipid interactions. Two phosphoinositides, phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol 3-phosphate, are important for the ATP-dependent priming of the secretory apparatus prior to Ca(2+)-dependent exocytosis. Mechanisms that control phosphoinositide levels are likely to play an important role in priming fine tuning. Here we have investigated the involvement of PIKfyve, a phosphoinositide 5-kinase that can phosphorylate phosphatidylinositol 3-phosphate to produce phosphatidylinositol 3,5-bisphosphate on large dense core vesicle exocytosis from neuroendocrine cells. PIKfyve localizes to a subpopulation of secretory granules in chromaffin and PC12 cells. Nicotine stimulation promoted recruitment of PIKfyve-EGFP onto secretory vesicles in PC12 cells. YM-201636, a selective inhibitor of PIKfyve activity, and PIKfyve knockdown by small interfering RNA potentiated secretory granule exocytosis. Overexpression of PIKfyve or its yeast orthologue Fab1p inhibited regulated secretion in PC12 cells, whereas a catalytically inactive PIKfyve mutant had no effect. These results demonstrate a novel inhibitory role for PIKfyve catalytic activity in regulated secretion and provide further evidence for a fine tuning of exocytosis by 3-phosphorylated phosphoinositides.

Polyethylene Gel in the Subcutaneous Tissue of Rats: Histopathologic and Systemic Evaluation

Purpose: To evaluate the histological and systemic response to subcutaneous injection of polyethylene gel in rats. Methods: Twenty-one white male rats were divided into 3 groups (G): G1 and G2 received subcutaneous polyethylene gel injection in the dorsal midline and were sacrificed at 30 and 60 postoperative days, respectively. G3 was not exposed to the polyethylene gel and was sacrificed after 60 days. Blood levels of lactate dehydrogenase (LDH), creatine kinase (CK), and alkaline phosphatase (ALP) were evaluated. The heart, kidney, liver, adrenal gland, injection site, and adjacent tissues were histologically examined. The results were submitted to statistical analysis. Results: There was no clinical evidence of extrusion, reduction of the injected volume, or abnormalities in the adjacent tissues. Blood levels of CK and LDH were normal and similar in all groups. ALP levels were significantly lower in G2 than in G1 and G3. The systemic organs were normal on histological examination in the 3 groups evaluated. Microscopically, the polyethylene gel was surrounded by a thin pseudocapsule formation and minimal inflammatory cell response, which decreased from G1 to G2. Conclusion: The subcutaneous injection of polyethylene gel in rats elicited minimal local inflammatory response and no systemic side effects.

RhBMP-2 using biphasic calcium phosphate block as a carrier induces new bone formation in a rat subcutaneous tissue

Purpose: The carrier for the delivery of bone morphogenetic proteins(BMPs) should also serve as a scaffold for new bone growth. In addition, predictable bone formation in terms of the volume and shape should be guaranteed. This study evaluated the ectopic bone formation of recombinant human BMP-2(rhBMP-2) using a micro macroporous biphasic calcium phosphate (MBCP: mixture of β-TCP and HA) block as a carrier in a rat subcutaneous assay model. Materials and Methods: Subcutaneous pockets were created on the back of 40 male Sprague-Dawley rats. In the pockets, rhBMP-2/MBCP and MBCP alone were implanted. The blocks were evaluated by histological and histometric parameters after a healing interval of 2 weeks (each 10 rats; MBCP and rhBMP-2/MBCP) or 8 weeks (each 10 rats; MBCP and rhBMP-2/MBCP). Results: The shape and volume of the block was maintained stable over the healing period. No histological bone forming activity was observed in the MBCP alone sites after 2 weeks and there was minimal new bone formation at 8 weeks. In the rhBMP-2/MBCP sites, new bone formation was evident in the macropores of the block. The new bone area at 8 weeks was greater than at 2 weeks. There was a further increase in the quantity of new bone with the more advanced stage of remodeling. Conclusions: A MBCP block could serve as a carrier system for predictable bone tissue engineering using rhBMPs. (J Korean Acad Periodontol 2008;38:355-362)

In Vivo Behavior of Poly(∈-Caprolactone-co-DL-Lactide)/Bioactive Glass Composites in Rat Subcutaneous Tissue

In this study, tissue reactions and possible toxicological responses of two different bioactive and degradable composite materials consisting of poly( ∈-caprolactone-co-DL-lactide) and bioactive glass (S53P4) granules were evaluated. The chosen materials were implanted subcutaneously in the back of rats for six months. The glass granules retained their bioactivity within the polymer matrices. A fibrous capsule formed around all tested materials and around the materials containing bioactive glass the fibrous capsules appeared to be thicker. Tissue growth into these materials was observed during the healing period while no growth was noticed into the plain polymer matrices. No adverse reactions were seen with any of the evaluated materials.

Tesaglitazar, a PPARα/γ Agonist, Induces Interstitial Mesenchymal Cell DNA Synthesis and Fibrosarcomas in Subcutaneous Tissues in Rats

The development of the dual peroxisome proliferator-activated receptor (PPAR) alpha/gamma agonist tesaglitazar as an oral antidiabetic was recently discontinued. Here we present tumor data from a 2-year carcinogenicity study in rats given 0.3, 1, 3, and 10 micromol/kg tesaglitazar is presented with focus on the findings of subcutaneous fibrosarcomas. To investigate the mechanism for induction of fibrosarcomas, replicative DNA synthesis (immunohistochemical detection of BrdU-labeled cells) and expression of PPARgamma (immunohistochemistry and reverse transcription-polymerase chain reaction) in subcutaneous adipose tissues was assessed in rats administered 1 or 10 micromol/kg for 2 weeks or 3 months. Poorly differentiated subcutaneous mesenchymal sarcomas with a predominant spindle cell appearance occurred at the highest dose level of 10 micromol/kg in both sexes, and these tumors were diagnosed as fibrosarcomas. The 10-micromol/kg dose was at or above the maximum tolerated dose and caused considerable cardiovascular mortality. Tesaglitazar stimulated DNA synthesis mainly in subcutaneous interstitial mesenchymal cells. The percentage of BrdU-labeled interstitial cells was increased at 1 and 10 micromol/kg after 2 weeks. The increase in DNA synthesis was still significant at the end of the 12-week treatment at 10 mumol/kg, the dose producing fibrosarcoma. However, at 1 micromol/kg, a dose below the no-observed-effect level for fibrosarcoma, the level of DNA synthesis was similar to control levels at 12 weeks. Immunohistochemical analyses showed no detectable PPARgamma protein in the majority of BrdU-labeled interstitial mesenchymal cells in white and brown fat. This indicates that stimulation of DNA synthesis is not mediated via direct activation of PPARgamma in these cells. The results suggest that the induction of rat fibrosarcoma by tesaglitazar, at exposures 100-fold above the human therapeutic exposure, may involve proliferation of undifferentiated mesenchymal cells in subcutaneous tissues.

Assessment of in vitro and in vivo recovery of sinomenine using microdialysis

For microdialysis studies in the skin, laboratory-made linear probes are often used. The application of the microdialysis technique to the investigation of pharmacokinetics and pharmacodynamics of drugs requires careful assessment of the linear probes' performance to ensure validity of the data obtained using this technique. The aim of this study was to establish and validate the microdialysis technique for investigation of the pharmacokinetics and pharmacodynamics of sinomenine. Using different lengths of the dialysis membrance and different perfusion flow rates, a flow rate of 2 microL/min with 20-min sampling intervals was selected for the subsequent studies, based on the analysis of sinomenine from the microdialysis probe. In vitro recovery of sinomenine from the microdialysis probe was independent of concentration, stable over an 8-h period. Comparable in vitro recoveries were obtained by different established approaches including recovery estimation by gain, loss and the zero-net flux (ZNF) method. Recovery by loss was used to study the in vivo recovery of sinomenine from rat subcutaneous tissue. The performance of the microdialysis system was stable over an 8-h study, resulting in a mean in vitro recovery of 51.91+/-1.29%. Recovery obtained using the ZNF plot was 52.43%. In vivo recovery of sinomenine was 34.46+/-0.76% and was stable over the 7-h study period. The in vitro and in vivo performance of the microdialysis technique was established for the study of sinomenine. It would prove to be a useful and reliable tool to study the pharmacokinetics and pharmacodynamics of sinomenine. The data obtained in our study highlight the importance of a systematic examination of microdialysis linear probe validation.

Novel Method of Decellularization of Porcine Valves Using Polyethylene Glycol and Gamma Irradiation

Recent tissue-engineered valves are in need of a breakthrough to overcome several limitations against clinical applications. We have developed a new method of decellularization using polyethylene glycol and gamma irradiation. Fresh porcine aortic valves were decellularized using polyethylene glycol and gamma irradiation. These were evaluated by histologic, biochemical (DNA, solubilized protein and collagen content), mechanical (strength test, transmission electron microscopy) and immunologic (porcine endogenous retrovirus and the alpha-1.3 galactosyl epitope) analyses. Implantations into the subcutaneous tissue of rats (1 week, n = 10; 2 months, n = 10) and into the descending aorta of dogs (2 months, n = 6; 6 months, n = 3) were used as in vivo studies. Complete decellularization was confirmed by histologic examination and by determining the DNA and solubilized protein content. The decellularized valve showed no significant differences in its mechanical strength or collagen content compared with native porcine tissues. The ultrastructure was well preserved in transmission electron microscope images. The DNA sequence of a porcine endogenous retrovirus and the alpha-1.3 galactosyl epitope were eliminated after the decellularizing process. No acute rejection and little calcification was noted in the rat model. In the dog model at 2 months, the surface of the graft was completely covered with a monolayer of endothelial cells. In addition, several layers of vimentin-positive cells lay under the endothelial cells. At 6 months after implantation, many smooth muscle cells, monolayer endothelial cells, and some vasculogenesis were seen. The decellularizing method provided low immunogenicity, low risk of unknown infections, and was little subject to calcification. The decellularized tissues showed acceptable durability and recellularization.

Changes in the rat subcutaneous connective tissue after saline and histamine injection in relation to fluid storage and excretion

An experimental design was developed for morphometric analysis of the subcutaneous connective tissue after the subcutaneous injection of 0.1 ml of saline or a histamine solution (0.01, 0.1 or 1% histamine dihydrochloride in saline). The subcutaneous connective tissue of 4-week-old rats, originally 170.0 +/- 13.6 mum in thickness, swelled 5.2-fold at 15 min, 3.0-fold at 2 h, and 1.2-fold at 6 h after the injection of saline. The total cross sectional area of both blood and lymphatic vessels increased when compared to that at pre-injection (0.0186 +/- 0.0030 mm(2) in 6-mm-long specimen), 1.4-fold at 15 min, 2.2-fold at 2 h, and 1.1-fold at 6 h post-injection, while the total number of these vessels increased 1.1-fold at 2 h. The total cross sectional area of lymphatic vessels (0.0006 +/- 0.0002 mm(2) in 6-mm-long specimen) alone surged 7.7-fold at 15 min, 4.8-fold at 2 h, and 7.3-fold at 6 h. Collagen fibers were respectively highly, moderately, and mildly disorganized in arrangement at 15 min, 2 h, and 6 h after the saline injection. Histamine elicited an earlier, longer, and more pronounced vasodilatation, particularly at high concentrations. The transvascular permeability of Evans blue increased depending on the concentration of histamine. These findings indicate that the subcutaneous connective tissue has the ability to expand and store a considerable amount of fluid and reversibly returns to normal steady-state conditions by increasing fluid excretion into the blood and lymphatic vessels. It was also strongly suggested that the blood vessels are deeply involved in the excretion and volume regulation of the tissue fluid.

Reactions of Connective Tissue to Amalgam, Intermediate Restorative Material, Mineral Trioxide Aggregate, and Mineral Trioxide Aggregate Mixed With Chlorhexidine

The aim of this study was to histopathologically examine the biocompatibility of the high-copper amalgam, intermediate restorative material (IRM), mineral trioxide aggregate (MTA), and MTA mixed with chlorhexidine (CHX). This study was conducted to observe the rat subcutaneous connective tissue reaction to the implanted tubes filled with amalgam, IRM, MTA, and MTA mixed with CHX. The animals were sacrificed 15, 30, and 60 days after the implantation procedure. The implant sites were excised and prepared for histological evaluation. Sections of 5 to 6 μm thickness were cut by a microtome and stained with hemotoxylin eosin and examined under a light microscope. The inflammatory reactions were categorized as weak (none or few inflammatory cells ≤25 cells), moderate (>25 cells), and severe (a lot of inflammatory cells not to be counted, giant cells, and granulation tissue). Thickness of fibrous capsules measured five different areas by the digital imaging and the mean values were scored. Amalgam, IRM, and MTA mixed with CHX caused a weak inflammatory response on days 15, 30, and 60. MTA provoked an initial severe inflammatory response that subsided at the 30 and 60 day study period. A clear fibrous capsule was observed beginning from the 15 days in all of the groups. Within the limits of this study, amalgam, IRM, MTA, and MTA mixed with CHX materials were surrounded by fibrous connective tissue indicated that they were well tolerated by the tissues, therefore, MTA/CHX seemed to be biocompatible.

Dynamics of Subcutaneous Tissue Response to the Implantation of Tetracycline-Treated or Untreated Membrane of Demineralized Bovine Cortical Bone in Rats

This study aims to conduct a histological evaluation of tissue response to a membrane obtained from demineralized bovine cortical bone, associated or not, to tetracycline (TTC). TTC treated and untreated bovine membranes were implanted in the subcutaneous tissue of rats (n = 120). The animals were killed 1, 3, 7, 15, 30, and 60 days after surgery. The tissue around the material was fixed in 10% buffered formalin for 24 h. Sections of 6 mm were stained with hematoxylin and eosin. In general, moderate to intense inflammatory response was observed in the initial periods (1 and 3 days), moderate response in the 7- and 15-day periods, and that was remarkably reduced at 30 and 60 days. Resorptions of the membranes by mononuclear cells (fibroblasts and macrophages) and multinucleated giant cells were observed 15 days after implantation. Only the remnants of the material could be detected in some animals in 60 days. Both membranes were tolerated by the tissue and were completely resorbed after 30-60 days. While the association of TTC apparently accelerated the biodegradability of the membrane substrate, no significant differences were found in the tissue response behavior between the two groups tested.

Histological analysis of the biocompatibility of three different calcium hydroxide-based root canal sealers

Objective:To histologically evaluate the behavior of the subcutaneous tissue of rats after placement of polyethylene tubes filled with calcium hydroxide-based root canal sealers (Sealapex™, Apexit™ e Sealer 26™).Study design:The study employed 60 rats, which were divided into eight groups, being four experimental groups with 10 rats each, and four control groups with five rats. Analysis was conducted at 48 hours, 7, 21 and 60 days. Results: Histological analysis revealed that all sealers were irritant; however, the intensity varied between each sealer and as a function of time. At the initial periods (48 hours and seven days), all materials demonstrated similar outcomes, with inflammatory reaction from severe to moderate, respectively. At the final periods (21 and 60 days), the tissue reactions to the implants containing Sealapex™ displayed an active status yet with regression, compared to the Apexit™ and Sealer 26™. The control groups exhibited less inflammatory cells than the experimental groups, keeping a reaction status with regression.Conclusions:The results achieved in this study revealed that the Sealapex™ sealer was the most compatible, followed by Apexit™ and Sealer 26™

Tissue reaction and surface morphology of absorbable sutures after in vivo exposure

Tissue reaction to suture materials depends mainly on how the polymer they are composed of interacts with the tissues. There are few in vivo studies evaluating the suture material modifications resulting from its interaction with tissues. This paper aimed to study rat subcutaneous tissue reaction to irradiated polyglactin 910, polydioxanone, poliglecaprone 25 and chromic gut and its correlation with the ultra-structural alterations the materials undergo. The histological alterations were studied on the 1st, 2nd, 3rd, 7th and 14th day after suture implantations. In these periods, the materials were removed from the tissues and their surfaces were analyzed by scanning electron microscopy. Irradiated polyglactin 910 stimulated the formation of multinucleated giant cells and its filaments underwent cleavage and dissolution. In potydioxanone, a few inflammatory cells and scar fibrosis was observed, and triangular cracks appeared on its surface. Around the poliglecaprone 25, a diffused infiltration of a few mononuclear cells and fibrosis was recorded and formation of craters was observed on its surface. Chromic gut induced necrosis and granulation tissue and underwent dissolution in the tissues during the studied periods. In this study, it was observed that suture materials induced differentiated tissue reactions and morphologic surface changes, suggesting that indications should be individualized.