Biochemical and Biomechanical Analysis of Tendons of Caged and Penned Chickens

Benevides, Gustavo Pereira; Pimentel, Edson Rosa; Toyama, Marcos H.; Novello, José Camillo; Marangoni, Sérgio; Gomes, Luiz Fernando

doi:10.1080/03008200490522997

Cited by 29 publications

(27 citation statements)

References 64 publications

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“…We have found no information concerning the presence of AR in tendon fibroblasts (tenocytes) in the literature. Nevertheless, inactivity, exercise, or steroid hormones levels have been associated with adaptive changes in the morphology, mechanical properties, and/or molecular biology of tendons (Simonsen et al 1995;Birch et al 1999;Järvinen et al 2002;Benevides et al 2004;See et al 2004;Kjaer et al 2006;Marqueti et al 2006Marqueti et al , 2008 or even with tendon pathologies (Michna 1987;Laseter and Russell 1991;Miles et al 1992;Visuri and Lindholm 1994;Evans et al 1998). Since tendons connect muscles to bones and have a key role in musculoskeletal biomechanics, the augmented muscle power and mass described for AAS users or keen sporting persons will probably be reflected in tendon response to the new loading conditions.…”

Section: Introductionmentioning

confidence: 99%

Effect of high intensity aerobic exercise and mesterolone on remodeling of Achilles tendon of C57BL/6 transgenic mice

et al. 2009

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The effect of mesterolone and intensive treadmill training (6 weeks, 5 days/week, means: 15.82 m/min and 45.8 min/day) in Achilles tendon remodeling was evaluated. Sedentary mice treated with mesterolone (Sed-M) or vehicle (Sed-C, placebo/control) and corresponding exercised (Ex-M and Ex-C) were examined. SDS-polyacrylamide gel electrophoresis was used for determining collagen bands and hydroxyproline concentration. Collagen fibril diameter, the area and number of fibrils contained in an area probe, and the ultrastructure of fibroblasts (tenocytes) were determined. The presence of collagen was notable in the tendons of all groups. Collagen alpha(1/)alpha(2) bands in Sed-M, Ex-C, and Ex-M were higher than in Sed-C, as shown by hydroxyproline content, but collagen beta-chain appeared only in Ex-C. Noticeable bands of non-collagenous proteins were found in Sed-M and Ex-M. The number of fibrils in the area probe increased markedly in Sed-M and Ex-C (12-fold), but their diameter and area were unchanged compared with Sed-C. In Ex-M, the fibril number decreased by three-fold to 3.5-fold compared with Sed-M and Ex-C, whereas diameter and area increased. Sed-C tenocytes appeared quiescent, whereas those in the other groups seemed to be engaged in protein synthesis. The density of tenocytes was smaller in Sed-C than in Ex-C, Sed-M, and Ex-M. Thus, mechanical stimuli and mesterolone alter the morphology of tenocytes and the composition of the tendon, probably through fibrillogenesis and/or increased intermolecular cross-links. The ergogenic effect is evidenced by the activation of collagenous and non-collagenous protein synthesis and the increase in the diameter and area of collagen fibrils. This study might be relevant to clinical sports medicine.

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Section: Introductionmentioning

confidence: 99%

Effect of high intensity aerobic exercise and mesterolone on remodeling of Achilles tendon of C57BL/6 transgenic mice

et al. 2009

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“…With respect to the amount of GAGs, Benevides et al (2004) carried out a comparative study with the superficial flexor tendon from caged and penned chickens. They did not observe any difference between these two groups in the GAG content in the compression region.…”

Section: Discussionmentioning

confidence: 99%

Effects of stretching on morphological and biochemical aspects of the extracellular matrix of the rat calcaneal tendon

et al. 2010

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Several studies have demonstrated the relationship between exercise and the extracellular matrix of muscle tendons, and have described alterations in their structural and biochemical properties when subjected to strenuous exercise. However, little is known about what happens to tendons when they are subjected to stretching. We evaluated the changes in the composition and structure of rat calcaneal tendons subjected to a stretching program. The animals had their muscles stretched for 30 s with 30 s of rest, with 10 repetitions, three and five times a week for 21 days. For morphological analysis, the sections were stained with hematoxylin-eosin and toluidine blue. For biochemical analysis, the tendons were treated with 4 M guanidine hydrochloride and analyzed in SDS-PAGE. The contents of total proteins and glycosaminoglycans were also measured. In the sections stained with toluidine blue, we could observe an increase of rounded cells, especially in the enthesis region. In the region next to the enthesis was a metachromatic region, which was more intensely stained in the stretched groups. In the tension regions, the cells appeared more aligned. Cellularity increased in both regions. The SDS-PAGE analysis showed a larger amount of collagen in the stretched groups and a polydispersed component of 65 kDa in all the groups. The amounts of proteins and glycosaminoglycans were also larger in the stretched tendons. The agarose-gel electrophoresis confirmed the presence of dermatan sulfate in the tension and compression regions, and of chondroitin sulfate only in the latter. Our results showed that the stretching stimulus changed the cellularity and the amount of the extracellular matrix compounds, confirming that tendons are dynamic structures with a capacity to detect alterations in their load.

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“…The structural arrangements of the collagen fibrils and their association to other extracellular matrix components, such as proteoglycans and metalloproteinases, are responsible for the tendon biomechanical properties [10]. With ageing, there is a decrease in the proteoglycans and water content along with reduction in collagen turnover and in the synthesis of collagenolytic enzymes, predisposing the tissue to lesions [11].…”

Section: Introductionmentioning

confidence: 99%