Statins induce biochemical changes in the Achilles tendon after chronic treatment

AbstractStatins 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

Effect of inflammation in rat paw induced by carrageenan on the deep digital flexor tendon

Orientador: Edson Rosa PimentelDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de BiologiaResumo: Os tendões podem ser acometidos por lesões, infecções e inflamações, seguidas ou não de ruptura, podendo ser decorrentes de atividades desportivas, como exercícios e alongamentos, ou de atividades diárias de muitos trabalhadores. Em situações patológicas a matriz extracelular (MEC) do tendão passa por um processo de reorganização de seus componentes, visando à regeneração e homeostasia do tecido. A inflamação pode ser desencadeada por diferentes fatores, entre os principais causadores desse processo estão injúrias mecânicas e químicas, agentes infecciosos, queimadura, radiação e supressão de oxigênio. Pouco é conhecido na literatura sobre as possíveis alterações que a inflamação instalada em tecidos próximos pode ocasionar em tendões. Desse modo, o presente estudo teve por objetivo analisar as alterações bioquímicas e morfológicas do tendão flexor digital profundo (TFDP) após indução da inflamação aguda em pata. Os períodos de análises foram 4 horas, período em que ocorre o pico da inflamação, 12 e 24 horas. Ratos Wistar (140-160g) foram separados em três grupos experimentais: os que receberam aplicação da carragenina (1%), os que receberam NaCl (0,9%), e os que não receberam nada, sendo utilizados como controle. O TFDP foi dividido conforme suas diferentes regiões (distal, intermediária, proximal). Para análises bioquímicas, os tendões foram processados e analisados de acordo com as seguintes técnicas: SDS-PAGE, para observação do perfil de proteínas, eletroforese em gel de agarose para análise de glicosaminoglicanos sulfatados; zimografia para detecção de metaloproteínase (MMP) 2 e 9; e dosagem de proteínas não colagênicas e hidroxiprolina. Para análises morfológicas, os cortes foram corados com hematoxilina-eosina, azul de toluidina e ponceau SS. De acordo com nossos resultados, no pico da inflamação aguda foi observada menor quantidade de proteínas e glicosaminoglicanos nas três regiões do TFDP dos animais tratados com carragenina. A concentração de hidroxiprolina foi maior nas duas regiões de tensão do tendão do grupo inflamado. A presença da MMP-9 foi detectada na região distal e foi evidenciado o epitendão mais espesso com células inflamatórias nas três regiões do TFDP no grupo com carragenina. Uma melhor organização dos feixes de colágeno foi observada nas duas regiões de tensão desse mesmo grupo. Após o período de pico da inflamação foi evidenciado a presença da isoforma latente e ativa da MMP-9 em 12 horas após a indução da inflamação. Houve maior quantidade de hidroxiprolina na região intermediária e proximal no grupo de 12 horas e, na região distal no grupo de 24 horas no grupo tratado com carragenina. A concentração de proteínas foi menor na região distal do grupo tratado com carragenina em 12 horas e maior em 24 horas nessa mesma região e grupo. A presença de um epitendão mais espesso com infiltrado de células foi observado nas regiões do TFDP dos animais com carragenina em 24 horas e, a organização dos feixes de colágeno foi menor na região proximal em 12 e 24 horas foram mostradas nos animais que receberam o veículo e a carragenina. Nenhuma diferença foi encontrada durante 4, 12 e 24 horas nos géis de SDS-PAGE. Nossos resultados mostram que embora o tendão não esteja inflamado, durante o pico do processo inflamatório agudo na pata de rato, alterações marcantes são evidenciadas. Contudo, podem ser ressaltados que o período posterior ao pico da inflamação também desencadeia alterações nos elementos estruturais e bioquímicos da MEC do TFDPAbstract: The tendons are often affected by injuries, infections and inflammations, followed or not by rupture, which may occur during sport activities such as exercise and stretching, or during other daily activities. In pathological situations the extracellular matrix of tendons undergoes a reorganization process of their components, aimed at the improvement, regeneration and tissue homeostasis. Inflammation can be triggered by different factors, among the main causes of this process are mechanical and chemical injuries, infectious agents, burns, radiation and suppression of oxygen. Little is known in the literature on possible changes that the inflammation may trigger in near tissues where it is installed. This study aims to examine biochemically and morphologically the deep digital flexor tendon (DDFT) after induction of acute inflammation in rat paw (140-160g). The analysis was performed in the peak of inflammation (4 hours) and after that period (12 and 24 hours). Rats Wistar were divided into three groups: those who received application of (1%) carrageenan, those receiving 0.9% NaCl, and those who received nothing and were used as control. The DDFT was analyzed according to their regions (distal, intermediate and proximal). The DDFT was analyzed according to its different regions (distal, intermediate, proximal). For biochemical analysis, the tendons were processed and analyzed in accordance with the following techniques: SDS-PAGE, to observe the profile of proteins, agarose gel electrophoresis to analysis of sulfated glycosaminoglycans; zymography for detection of metalloproteinases 2 and 9, and dosage of non collagenous proteins and hydroxyproline. For morphological analysis, sections were stained with hematoxylin-eosin, toluidine blue and Ponceau SS. At the peak of acute inflammation was observed lower amount of proteins and glycosaminoglycans in the three regions of animals tendons with carrageenan. The hydroxyproline concentration was higher in the two tension regions of tendon of inflamed group. The presence of MMP-9 was detected in the distal region and was shown a thicker epitendon with inflammatory cells in the three regions of the DDFT in the group with carrageenan. Better organization of collagen bundles were observed within two regions of tension in the mentioned group. After the peak of inflammation was evidenced the presence of the latent and active isoform of the MMP-9 in 12 hours after induction of inflammation. A higher amount of hydroxyproline was detected in the intermediate and proximal region in the 12 hours and in the distal region in 24 hours in group treated with carrageenan. The protein concentration was lower in the distal region of the inflamed group at 12 hours and higher in 24 hours on the same region in the group treated with carrageenan. The presence of a thicker epitendon with cell infiltration was observed in the animals with DDFT of carrageenan animals as well as, a smaller organization of collagen bundles in the proximal region in 12 and 24 hours were shown in rats treated with vehicle and carrageenan. No difference was found for 4, 12 and 24 hours in SDS-PAGE gels. Our results show that although the tendon is not inflamed, during the peak of acute inflammation in rat paw, the most marked changes are evident. However, it can be emphasized that the period after the inflammation also triggers changes in the structural and biochemical components of the extracellular matrix of the deep digital flexor tendonMestradoBiologia CelularMestre em Biologia Celular e Estrutura

Green Tea And Glycine Modulate The Activity Of Metalloproteinases And Collagen In The Tendinitis Of The Myotendinous Junction Of The Achilles Tendon

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)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. (C) 2016 Wiley Periodicals, Inc.2997918928National Council for Scientific and Technological Development (CNPq - Brazil)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Glycine Improves Biochemical And Biomechanical Properties Following Inflammation Of The Achilles Tendon

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)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. (C) 2014 Wiley Periodicals, Inc.2983538545Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq

Birefringence Of Collagen Fibres In Rat Calcaneal Tendons Treated With Acupuncture During Three Phases Of Healing.

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. 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). 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). 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. Acupuncture, through putative anti-inflammatory and mechanotransductor effects, may have a role in strengthening tendons and increasing resistance to re-rupture.3427-3

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 repair2997918928CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICO - CNP

Alterations In The Achilles Tendon After Inflammation In Surrounding Tissue.

To analyze the characteristics of the Achilles tendon of rats after induction of localized inflammation in the rat paw. 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. 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. 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.20266-