Plasma microbiome in COVID-19 subjects: an indicator of gut barrier defects and dysbiosis.

The gut is a well-established route of infection and target for viral damage by SARS-CoV-2. This is supported by the clinical observation that about half of COVID-19 patients exhibit gastrointestinal ( GI ) symptoms. We asked whether the analysis of plasma could provide insight into gut barrier dysfunction in patients with COVID-19 infection. Plasma samples of COVID-19 patients (n=30) and healthy control (n=16) were collected during hospitalization. Plasma microbiome was analyzed using 16S rRNA sequencing, metatranscriptomic analysis, and gut permeability markers including FABP-2, PGN and LPS in both patient cohorts. Almost 65% (9 out 14) COVID-19 patients showed abnormal presence of gut microbes in their bloodstream. Plasma samples contained predominately Proteobacteria, Firmicutes, and Actinobacteria . The abundance of gram-negative bacteria ( Acinetobacter, Nitrospirillum, Cupriavidus, Pseudomonas, Aquabacterium, Burkholderia, Caballeronia, Parabhurkholderia, Bravibacterium, and Sphingomonas ) was higher than the gram-positive bacteria ( Staphylococcus and Lactobacillus ) in COVID-19 subjects. The levels of plasma gut permeability markers FABP2 (1282±199.6 vs 838.1±91.33; p=0.0757), PGN (34.64±3.178 vs 17.53±2.12; p<0.0001), and LPS (405.5±48.37 vs 249.6±17.06; p=0.0049) were higher in COVID-19 patients compared to healthy subjects. These findings support that the intestine may represent a source for bacteremia and may contribute to worsening COVID-19 outcomes. Therapies targeting the gut and prevention of gut barrier defects may represent a strategy to improve outcomes in COVID-19 patients.

Role of metalloproteinases and TNF-α in obesity-associated asthma in mice.

Numerous population studies conducted worldwide indicate that the prevalence of asthma is higher in obese versus lean individuals. It has been reported that sensitized lean mice has a better recovery of lung inflammation in asthma. Extracellular matrix (ECM) plays an essential role in the structural support of the lungs regulating the airways diameter, thus preventing its collapse during expiration. ECM renewal by metalloproteinase (MMPs) enzymes is critical for pulmonary biology. There seems to be an imbalance of MMPs activity in asthma and obesity, which can impair the lung remodeling process. In this study, we characterized the pulmonary ECM of obese and lean mice, non-sensitized and sensitized with ovalbumin (OVA). Pharmacological intervention was performed by using anti-TNF-α, and MMP-8 and MMP-9 inhibitors in obese and lean sensitized mice. Activity of MMPs was assessed by gelatinase electrophorese, western blotting and zymogram in situ. Unbalance of MMP-2, MMP-8, MMP-9 and MMP-12 was detected in lung tissue of OVA-sensitized obese mice, which was accompanied by high degradation, corroborating an excessive deposition of types I and III collagen in pulmonary matrix of obese animals. Inhibitions of TNF-α and MMP-9 reduced this MMP imbalance, clearly suggesting a positive effect on pulmonary ECM. Obese and lean mice presented diverse phenotype of asthma regarding the ECM compounds and the inhibition of MMPs pathway could be a good alternative to regulate the activity in ECM lungs of asthmatic obese individuals.

Chronical treatment with sildenafil causes Achilles tendinopathy in rats.

AIMS: The primary goal was to assess the effects of chronic sildenafil treatment over the Achilles tendons in rats. MAIN METHODS: Animals were divided into two groups, control and sildenafil administration (n = 5). After 60 days, the tendons were subject to biochemical and image analysis to compare tendons between the groups: collagen I and decorin content, polarisation microscopy and birefringence analysis, and tissue zymography. KEY FINDINGS: The animals exposed to sildenafil presented a much less organised tendon matrix, with reduced collagen I and non-collagenous protein content and a much higher decorin content. SIGNIFICANCE: The results observed in the animals can be characterised as tendinopathy, a condition not yet described as a sildenafil side effect.

Glycine improves the remodeling process of tenocytes in vitro.

Tendinitis changes the biochemical and morphological properties of the tendon, promoting an increase of activity of metalloproteinases and disorganization of collagen bundles. Tenocytes, the primary cells in tendon, are scattered throughout the collagenic fibers, and are responsible of tendon remodeling and tissue repair in pathological condition. In vivo, glycine, component of the typical Gly-X-Y collagen tripeptide, showed beneficial effects in biochemical and biomechanical properties of Achilles tendon with tendinitis. In this study, we analyzed the effect of glycine in tenocytes subjected to inflammation. Tenocytes from Achilles tendon of rats were treated with TNF-α (10 ng/mL) with and without previous treatment with glycine (20 mM). Cell proliferation and migration were evaluated, as well as the expression of matrix molecules such as glycosaminoglycans, metalloproteinases (MMPs), TIMPs, and collagen I. Glycine can revert the inflammation due to the action of TNF-α by controlling the MMPs quantity and activity. These data indicated that the molecules involved to remodeling process of extracellular matrix are modulated both by TNF-α and the availability of collagen precursors; in fact, this study indicates the glycine can be useful for treatment of inflammation and for modulating tenocytes metabolism in tendons.

Low level laser therapy accelerates the extracellular matrix reorganization of inflamed tendon.

In tendon lesions, inflammation indicates the beginning of tissue repair and influences cell proliferation and the remodeling of the extracellular matrix (ECM). Low level laser (LLL) therapy has been an important method to induce tissue repair, and several studies have sought to better understand the therapeutic possibilities of this modality. This study analyzed the effect of LLL on the ECM of rat tendons during the early phase of the inflammatory process. Wistar rats received an intratendinous application of carrageenan adjacent to the osteotendinous region in the right paw. The animals were divided into the following groups: G1-intact, G2-animals with no treatment after the inflammation induction, G3-animals treated with LLL 1 and 3h after induction of inflammation (4J/cm2 continuous). After 4h of application, the animals of the two groups were euthanized with isoflurane overdose. Our results demonstrate that LLL therapy can promote decrease in non-collagenous protein and glycosaminoglycans content, as well as an increase in metalloproteinases -9, which proved, for the first time, that LLL therapy promotes alterations in the inflamed tendons even when analyzed only four hours after this process occur and could be a useful tool to improve the balance in inflamed tissues.

Green Tea and Glycine Modulate the Activity of Metalloproteinases and Collagen in the Tendinitis of the Myotendinous Junction of the Achilles Tendon.

The myotendinous junction (MTJ) is the weakest element in the muscle-tendon unit of the heel, and thus the most susceptible to injuries. The scarcity of adequate treatments means that tendinitis is a major concern to athletes and other groups who depend on their physical fitness, although green tea and glycine have both been shown to have beneficial effects on the inflammation. The present study investigated the remodeling effects of green tea and glycine in the MTJ of rats with tendinitis. For this, male Wistar rats were divided into five groups: animals without tendinitis and animals with tendinitis; animals with tendinitis supplied with green tea; animals with tendinitis supplied with a glycine diet; animals with tendinitis supplied with a green tea and glycine diet. Tendinitis was induced and the treatment with green tea (700 mg/kg/day) and a 5% glycine diet lasted 7 days. The treatments regulated the activity of metalloproteinases (MMP)-2, -8, and -9, and induced the synthesis of type I collagen, glycosaminoglycans, and non-collagenous proteins. Changes were also noted in the compaction of the collagen molecules and the amount of tenocytes. When combined, green tea and glycine modulated the inflammatory process and induced the synthesis of the elements involved in the post-lesion recovery of the tissue. The data from the MTJ were different when compared with results already published using the whole Achilles tendon. These data indicate that each region of the inflamed tendon can exhibit different responses during the treatment and therefore, modify its extracellular matrix components to facilitate recovery and repair. Anat Rec, 299:918-928, 2016. © 2016 Wiley Periodicals, Inc.

Low-level laser therapy modulates pro-inflammatory cytokines after partial tenotomy.

Tendon injuries give rise to substantial morbidity, and current understanding of the mechanisms involved in tendon injury and repair is limited. This lesion remains a clinical issue because the injury site becomes a region with a high incidence of recurrent rupture and has drawn the attention of researchers. We already demonstrated that low-level laser therapy (LLLT) stimulates the synthesis and organization of collagen I, MMP-9, and MMP-2 and improved the gait recovery of the treated animals. The aim of this study was to evaluate the effects of LLLT in the nitric oxide and cytokines profile during the inflammatory and remodeling phases. Adult male rats were divided into the following groups: G1--intact, G2-- injured, G3--injured + LLLT (4 J/cm(2) continuous), G4--injured + LLLT (4 J/cm(2)-20 Hz--pulsed laser). According to the analysis, the animals were euthanized on different dates (1, 4, 8, or 15 days after injury). ELISA assay of TNF-α, IL-1ß, IL-10, and TGF-ß was performed. Western blotting of isoform of nitric oxide synthase (i-NOS) and nitric oxide dosage experiments was conducted. Our results showed that the pulsed LLLT seems to exert an anti-inflammatory effect over injured tendons, with reduction of the release of proinflammatory cytokines, such as TNF-α and the decrease in the i-NOS activity. Thanks to the pain reduction and the facilitation of movement, there was a stimulation in the TGF-ß and IL-1ß release. In conclusion, we believe that pulsed LLLT worked effectively as a therapy to reestablish the tendon integrity after rupture.

Birefringence of collagen fibres in rat calcaneal tendons treated with acupuncture during three phases of healing.

BACKGROUND: Birefringence is an optical anisotropy that is investigated by polarisation microscopy, and has been valuable for the study of the oriented organisation of collagen fibres in tendons. However, the application of this technology to evaluate the effect of different acupuncture points during tendon healing has not yet been described. OBJECTIVES: To evaluate the concentration of non-collagenous proteins (NCP) and birefringence in rat calcaneal tendons following injury during the three different phases of healing: inflammatory (7th day), proliferative (14th day), and remodelling (21st day). METHODS: Tendons of 120 Wistar rats were tenotomised and left untreated (teno group, n=24), treated with manual acupuncture at ST36 (ST36 group, n=24), BL57 (BL57 group, n=24) or ST36+BL57 (SB group, n=24), or treated with electroacupuncture at ST36+BL57 (EA group, n=24). Tendon samples were collected at 7, 14 and 21 days after injury (n=8 per group). NCP concentrations were measured using the Bradford method (n=4 each) and birefringence was examined using polarisation microscopy and image analysis (n=4 each). Comparison was also made with healthy (non-tenotomised) tendons in a subgroup of rats (n=4 each). RESULTS: Manual acupuncture at ST36 and BL57 increased molecular organisation of collagen fibres on day 14 and 21 after injury. Isolated use of BL57 and ST36 also increased collagen fibre organisation when examined on day 14 and 21, respectively. No significant increase in NCP concentration was observed in any of the treated tenotomised groups. CONCLUSIONS: Acupuncture, through putative anti-inflammatory and mechanotransductor effects, may have a role in strengthening tendons and increasing resistance to re-rupture.

Glycine improves biochemical and biomechanical properties following inflammation of the achilles tendon.

Tendinopathy of the Achilles tendon is a clinical problem that motivates the scientific community to search for treatments that assist in restoring its functional properties. Glycine has broad biological effects, acting as a modulator of the inflammatory cascade, and is the predominant amino acid in collagen. A 5% glycine diet provided beneficial effects against toxicity and inflammation since glycine may restructure the collagen molecules faster due to its broad anti-inflammatory effects. The purpose was analyze the effects of a 5% glycine diet in rats as a treatment for the inflammatory process. The experimental groups were as follows: C (control group), G1 and G3 (inflammatory group), and G2 and G4 (glycine+inflammatory group). G1 and G2 were euthanized 8 days following injury, and G3 and G4 were euthanized 22 days following injury. The concentrations of hydroxyproline, non-collagenous proteins, and glycosaminoglycans, as well as the activity of MMP-2 and -9 were analyzed. Biomechanical and morphological tests were employed. Higher concentrations of hydroxyproline and glycosaminoglycans were found in G4 and an increased activity of MMP-2 was found in G2. Higher birefringence was noted in group G2. The biomechanical results indicated that the tendon was more resistant to loading to rupture upon treatment with a glycine diet in group G4. Glycine induced the synthesis of important components of the tendon. A rapid remodeling was noted when compared with the inflamed-only groups. These data suggest that glycine may be a beneficial supplement for individuals with inflammation of the Achilles tendon.

Acupuncture increases the diameter and reorganisation of collagen fibrils during rat tendon healing.

BACKGROUND: Our previous study showed that electroacupuncture (EA) increases the concentration and reorganisation of collagen in a rat model of tendon healing. However, the ultrastructure of collagen fibrils after acupuncture is unknown. OBJECTIVES: To assess the effect of acupuncture protocols on the ultrastructure of collagen fibrils during tendon healing. METHODS: Sixty-four rats were divided into the following groups: non-tenotomised (normal group), tenotomised (teno group), tenotomised and subjected to manual acupuncture at ST36 (ST36 group), BL57 (BL57 group) and ST36+BL57 (SB group) and EA at ST36+BL57 (EA group). The mass-average diameter (MAD) and the reorganisation of collagen fibril diameters were determined during the three phases of tendon healing (at 7, 14 and 21 days). RESULTS: The MAD increased during the three phases of healing in the SB group. In the EA group, MAD increased initially but was reduced at day 21. The reorganisation of collagen fibrils was improved in the EA and SB groups at days 14 and 21, respectively. EA at day 21 appeared to reduce the reorganisation. CONCLUSIONS: These results indicate that the use of EA up to day 14 and manual acupuncture at ST36+BL57 up to day 21 improve the ultrastructure of collagen fibrils, indicating strengthening of the tendon structure. These data suggest a potential role for acupuncture in rehabilitation protocols.

A hypothesis for the anti-inflammatory and mechanotransduction molecular mechanisms underlying acupuncture tendon healing.

A previous study demonstrated that acupuncture increases the synthesis and reorganisation of collagen molecules in rat tendons after injury. Clinical studies have shown that acupuncture improves pain and functional activity in patients with tendinopathy. However, the molecular mechanisms underlying these effects are unknown. Recent studies have shown that acupuncture can modulate both anti-inflammatory (AI) and mechanotransduction (MT) molecular pathways. Moreover, the modulation of these pathways can increase type I collagen synthesis, which is the main factor that influences tendon biomechanical properties. Our hypothesis is that acupuncture increases synthesis and subsequent reorganisation of type I collagen during tendon healing by concomitant modulation of the Toll-like receptor-nuclear factor-κB AI pathway, the mitogen-activated protein kinases pathway and the Rho/Rac-F-actin MT pathway. Increased collagen synthesis and reorganisation requires that at least one acupoint is anatomically connected with the site of the injury because of the local tenoblast MT mechanism. Confirmation of this hypothesis will increase the knowledge of acupuncture modulation of the previously mentioned molecular pathways, and such confirmation may also help to establish the relationships between the different types of acupuncture needle stimulation and the influence of acupuncture stimuli on pathway activity levels. In addition, the downstream therapeutic effects of acupuncture therapy may be established. This hypothesis can be verified in a rat tendon healing model, and subsequent clinical protocols for tendon healing can be developed and evaluated as standalone therapies or as a component of a combination therapy.

Pulsed LLLT improves tendon healing in rats: a biochemical, organizational, and functional evaluation.

In the last decades, the tendon injuries have increased substantially. Previous results suggested that low-level laser treatment (LLLT) promotes synthesis of extracellular matrix and improves the functional properties of the tendon. The aim of this study was to evaluate the effects of different protocols of LLLT on partially tenotomized tendons. Adult male rats were divided into the following: G1-intact, G2-injured, G3-injured + LLLT (4 J/cm(2) continuous), G4-injured + LLLT (4 J/cm(2) at 20 Hz). G2, G3, and G4 were euthanized 8 days after injury. G5-injured, G6-injured + LLLT (4 J/cm(2) continuous), and G7-injured + LLL (4 J/cm(2) at 20 Hz until the seventh day and 2 kHz from 8 to 14 days). G5, G6, and G7 were euthanized on the 15th day. Glycosaminoglycan (GAG) level was quantified by dimethylmethylene blue method and analyzed on agarose gel. Toluidine blue (TB) stain was used to observe metachromasy. CatWalk system was used to evaluate gait recovery. Collagen organization was analyzed by polarization microscopy. The GAG level increased in all transected groups, except G5. In G6 and G7, there was a significant increase in GAG in relation to G5. In G3 and G4, the presence of dermatan sulfate band was more prominent than G2. TB stains showed intense metachromasy in the treated groups. Birefringence analysis showed improvement in collagen organization in G7. The gait was significantly improved in G7. In conclusion, pulsed LLLT leads to increased organization of collagen bundles and improved gait recovery.

Statins induce biochemical changes in the Achilles tendon after chronic treatment.

Statins have been widely prescribed as lipid-lowering drugs and are associated with tendon rupture. Therefore, this study aimed to evaluate the possible biochemical changes in the Achilles tendon of rats after chronic treatment with statins. Dosages of statins were calculated using allometric scaling with reference to the 80mg/day and 20mg/day, doses recommended for humans. The rats were divided into the following groups: treated with simvastatin (S-20 and S-80), treated with atorvastatin (A-20 and A-80), and the control group that received no treatment (C). Measurements of low-density lipoprotein (LDL) in the plasma were performed. The levels of non-collagenous proteins, glycosaminoglycans (GAGs) and hydroxyproline were quantified. Western blotting for collagen I was performed, and the presence of metalloproteinases (MMPs)-2 and -9 was investigated through zymography. The concentration of non-collagenous proteins in S-20 was less than the C group. There was a significant increase in pro-MMP-2 activity in A-80 group and in active MMP-2 in S-20 group compared to the C group. A significant increase in latent MMP-9 activity was observed in both the A-80 and S-20 groups when compared to C group. In the A-20 group, there was a lower amount of collagen I in relation to C group. In addition, a higher concentration of hydroxyproline was found in the S-20 group than the C group. The analysis of GAGs showed a significant increase in the A-20 group when compared to C group. The treatment induced remarkable alterations in the Achilles tendon and the response of the tissue seems to depend of the used statin dosage. The presence of MMP-2 and MMP-9 is evidence of the degradation and remodeling processes in the extracellular matrix of the tendons. Our results show that statins induce imbalance of extracellular matrix components and possibly induce microdamage in tendons.

Inflammatory process induced by carrageenan in adjacent tissue triggers the acute inflammation in deep digital flexor tendon of rats.

Tendinopathy is a pathology found mainly in the rotator cuff, patellar, Achilles and flexor tendons. Tendinopathy is a significant impediment to performance in athletes and in workers in the labor market. Some studies have indicated that inflammation in adjacent tissues may affect the rotator cuff and Achilles tendon. In this study alterations were verified in the extracellular matrix (ECM) of the deep digital flexor tendon after two periods (12 and 24 hr) of induction inflammation in rat paw. Wistar rats were divided into three groups: those that received injection of 1% carrageenan; those that received 0.9% NaCl; and those that received no application. The tendon was divided into distal (d), proximal (p), and intermediate (i) regions. Biochemical analyses were performed and included non-collagenous proteins (NCP), glycosaminoglycans (GAGs), hydroxyproline (HoPro) and metalloproteinases 2 and 9. Tissue sections were stained with toluidine blue, hematoxylin-eosin, and Ponceau SS and observed under polarization microscopy. Remarkable results were detected that included the presence of MMP-9, degradation of NCP and GAG and the presence of cellular infiltrate closer to digits in d region. The different concentrations of HoPro, as well as alterations in the organization of the collagen fibers showed the collagenous matrix undergoing some alterations. The results indicated that the induced inflammation in rat paw exhibited characteristics similar to the typical acute inflammatory process observed in tendons.

LLLT improves tendon healing through increase of MMP activity and collagen synthesis.

The Achilles tendon has a high incidence of rupture, and the healing process leads to a disorganized extracellular matrix (ECM) with a high rate of injury recurrence. To evaluate the effects of different conditions of low-level laser (LLL) application on partially tenotomized tendons, adult male rats were divided into the following groups: G1, intact; G2, injured; G3, injured + LLL therapy (LLLT; 4 J/cm(2) continuous); G4, injured + LLLT (4 J/cm(2), 20 Hz); G5, injured; G6, injured + LLLT (4 J/cm(2) continuous); and G7, injured + LLLT (4 J/cm(2), 20 Hz until the 7th day and 2 kHz from 8 to 14 days). G2, G3, and G4 were euthanized 8 days after injury, and G5, G6, and G7 were euthanized on the 15th day. The quantification of hydroxyproline (HOPro) and non-collagenous protein (NCP), zymography for matrix metalloproteinase (MMP)-2 and MMP-9, and Western blotting (WB) for collagen types I and III were performed. HOPro levels showed a significant decrease in all groups (except G7) when compared with G1. The NCP level increased in all transected groups. WB for collagen type I showed an increase in G4 and G7. For collagen type III, G4 presented a higher value than G2. Zymography for MMP-2 indicated high values in G4 and G7. MMP-9 increased in both treatment groups euthanized at 8 days, especially in G4. Our results indicate that the pulsed LLLT improved the remodeling of the ECM during the healing process in tendons through activation of MMP-2 and stimulation of collagen synthesis.

Electroacupuncture increases the concentration and organization of collagen in a tendon healing model in rats.

The aim of this study was to investigate the effect of electroacupuncture (EA) on the composition and organization of the extracellular matrix of the rat Achilles tendon after a partial transection during the proliferative phase of healing. Wistar rats were divided into three groups: rats that were not tenotomized (G1), tenotomized rats (G2), and rats that were tenotomized and submitted to EA (G3). EA was applied 15 days after injury at the ST36 and BL57 acupoints for 20 min, three times per week on alternate days for a total of six sessions. Biochemical analyses were performed using non-collagenous proteins, glycosaminoglycans, and hydroxyproline quantifications. An analysis of metalloproteinase-2 was carried out by zymography. The general organization of the extracellular matrix and the metachromasy of the tendons were analyzed under light microscopy. The organization of the bundles of collagen fibers was analyzed by birefringence analysis. The results showed that EA did not alter the concentration of non-collagenous proteins or glycosaminoglycans or the enzymatic activity of metalloproteinase-2 in the transected tendons. However, the concentration of hydroxyproline was significantly increased when these tendons were treated by EA. The analysis of birefringence showed a higher organization of collagen fibers in the group treated by EA. These results indicate, for the first time, that EA may offer therapeutic benefits for the treatment of tendon injuries by increasing the concentration of collagen and by inducing a better molecular organization of the collagen fibers, which may improve the mechanical strength of the tendon after injury.

Alterations in the Achilles tendon after inflammation in surrounding tissue.

OBJECTIVE: To analyze the characteristics of the Achilles tendon of rats after induction of localized inflammation in the rat paw. METHODS: IN OUR STUDY THREE GROUPS WERE USED: inflamed group with carrageenan in rat paw (G1); saline group (G2) and control group (G3). After 4 hours the animals were euthanized and the Achilles tendon removed. RESULTS: No significant differences were observed in the analysis of non-collagenous proteins, glycosaminoglycans and hydroxyproline in the groups but a tendency of reduction was verified in G1. As regards the organization of collagen molecules, no differences were observed between groups. With respect to MMPs activity, a stronger presence of the active isoform of MMP-2 in G1 was observed, suggesting that the remodeling was occurring. CONCLUSION: Thus, we conclude that the inflammatory process in rat paw may affect the remodeling of tendons located near the inflamed site. Level of Evidence I, Prognostic Studies - Investigating the Effect of a Patient Characteristic on the Outcome of Disease.

Effects of acute inflammation induced in the rat paw on the deep digital flexor tendon.

The tendon is commonly affected by inflammation, and in such situations, the tissue undergoes a process of reorganization of the extracellular matrix to improve and regenerate the affected region. Little is known about the mechanisms that trigger inflammation in the tissues surrounding the affected area. The objective of this study was to biochemically and morphologically analyze the deep digital flexor tendon at the peak of acute inflammation in the rat paw. Wistar rats were divided into the following three groups: those that received injection of 1% carrageenan, those that received 0.9% NaCl, and those that received nothing. The deep digital flexor tendon was divided into the distal, proximal, and intermediate regions. For biochemical analysis, the tendons were treated with guanidine hydrochloride and analyzed by sodium dodecyl sulfate-polyacrilamide gel electrophoresis. Proteins, glycosaminoglycans (GAGs), and hydroxyproline were quantified, and metalloproteinases were analyzed. The GAGs were analyzed by agarose gel electrophoresis. Tissue sections were stained with hematoxylin-eosin, toluidine blue, and Ponceau SS. The content of proteins and GAGs was smaller in the group receiving the application of carrageenan. The concentration of hydroxyproline in the two tendon regions that respond to tension forces was higher in the inflammation group. The metalloproteinase-9 was detected in the distal region, and a thicker epitenon with cellular infiltrate was observed in the groups with inflamed paws. Meanwhile, a better organization of collagen bundles was observed in the two tension regions of that same group. Our results show that although the tendon was not directly inflamed, changes in the surrounding structural and biochemical parameters were observed.

Alterações no tendão de Aquiles após inflamação em tecido adjacente / Alterations in the Achilles tendon after inflammation in surrounding tissue

OBJETIVO: Analisar as características de tendões de Aquiles de ratos após indução de processo inflamatório localizado na pata. MÉTODOS: Foram utilizados três grupos experimentais: grupo inflamado com carragenina na pata de rato (G1); grupo salina (G2) e grupo controle (G3). Após 4 horas os animais foram eutanaziados e o tendão de Aquiles foi removido. RESULTADOS:Não foram observadas diferenças significativas nas análises de proteínas não colagênicas, glicosaminoglicanos e hidroxiprolina, mas uma tendência a diminuição foi verificada em G1. Em organização de moléculas de colágeno não foram observadas diferenças entre os grupos. Com respeito à atividade de MMPs, foi observada uma presença maior da isoforma ativa da MMP-2 em G1, sugerindo que a remodelação do tecido está ocorrendo. CONCLUSÃO: Desta forma, nós concluímos que o processo inflamatório desencadeado em pata de rato pode afetar o remodelamento de tendões situados próximo ao local inflamado. Nível de Evidência I, Estudos Prognósticos - Investigação do Efeito de Característica de um Paciente Sobre o Desfecho da Doença.

OBJECTIVE: To analyze the characteristics of the Achilles tendon of rats after induction of localized inflammation in the rat paw. METHODS: In our study three groups were used: inflamed group with carrageenan in rat paw (G1); saline group (G2) and control group (G3). After 4 hours the animals were euthanized and the Achilles tendon removed. RESULTS: No significant differences were observed in the analysis of non-collagenous proteins, glycosaminoglycans and hydroxyproline in the groups but a tendency of reduction was verified in G1. About the organization of collagen molecules, no differences were observed between groups. With respect to MMPs activity, a stronger presence of the active isoform of MMP-2 in G1 was observed, suggesting that the remodeling was occurring. CONCLUSION: Thus, we conclude that the inflammatory process in rat paw may affect the remodeling of tendons located near the inflamed site. Level of Evidence I, Prognostic Studies - Investigating the Effect of a Patient Characteristic on the Outcome of Disease.