More resistant tendons obtained from the association of Heteropterys aphrodisiaca and endurance training

<p>Abstract</p> <p>Background</p> <p>Popular Brazilian medicine uses <it>Heteropterys aphrodisiaca </it>infusion as a tonic or stimulant, for the treatment of nervous debility and breakdown and for muscle and bone weakness. This study investigated the effects of <it>Heteropterys aphrodisiaca </it>infusion on the tendon properties and extracellular matrix of rats under endurance training.</p> <p>Methods</p> <p>Wistar rats were grouped as follows: CS- control sedentary, HS- <it>H. aphrodisiaca </it>sedentary, CT-control trained, HT- <it>H. aphrodisiaca </it>trained. The training protocol consisted in running on a motorized treadmill, five times a week, with weekly increase in treadmill speed and duration. Control groups received water while the HS and HT groups received <it>H. aphrodisiaca </it>infusion, daily, by gavage for the 8 weeks of training. Achilles tendons were frozen for biochemical and biomechanical analysis or preserved in Karnovsky's fixative, then processed for histomorphological analysis with light microscopy.</p> <p>Results</p> <p>Biomechanical analysis showed significant increase in maximum load, maximum stress, modulus of elasticity and stiffness of the HT animals' tendons. The metalloproteinase-2 activity was reduced in the HT group. The compression region of HT animals' tendons had a stronger and more intense metachromasy, which suggests an increase in glycosaminoglycan concentration in this region of the tendon. The most intense birefringence was observed in both compression and tension regions of HT animals' tendons, which may indicate a higher organizational level of collagen bundles. The hydroxyproline content increased in the HT group.</p> <p>Conclusions</p> <p>The association of endurance training with <it>H. aphrodisiaca </it>resulted in more organized collagen bundles and more resistant tendons to support higher loads from intense muscle contraction. Despite the clear anabolic effects of <it>Heteropterys aphrodisiaca </it>and the endurance exercise association, no side effects were observed, such as those found for synthetic anabolic androgenic steroids.</p

Matrix metallopeptidase 2 activity in tendon regions: effects of mechanical loading exercise associated to anabolic-androgenic steroids

Matrix metallopeptidases (MMPs) are responsible for degradation of the extracellular matrix components and tissue remodeling. To achieve a better understanding of AAS effects in rat tendon, MMP-2 activity in the proximal and distal regions of the calcanear tendon (CT) and proximal, intermediate and distal region of superficial (SFT) and deep flexor tendons (DFT) after mechanical load exercise associated with AAS was investigated. Animals were grouped into four groups: sedentary animals (S); sedentary animals with ASS supplementation (S + A); trained animals (T) and trained animals with AAS supplementation (T + A). Analysis of MMP activity in tendon extracts was done by gelatin zymography. Both proximal and distal regions of the calcanear tendon showed the lowest MMP-2 concentration and the highest proportion in MMP-2 active form. The intermediate region of the SFT differed (P < 0.01) from the proximal and distal regions with higher % of active MMP-2 in the sedentary group. The proportion of active MMP-2 decreased in the proximal region of the CT. AAS treatment strongly decreased both MMP-2 concentration and active form in the three regions of the SFT and on the proximal region of the CT, but not on the DFT. The differences in the response to exercise and AAS treatment are a result of distinct metabolism and recruitment of these tendon regions in the exercise program employed in this study.10461087109

Biomechanical responses of different rat tendons to nandrolone decanoate and load exercise

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Androgenic-anabolic steroids (AAS) have been associated with an increased incidence of tendon rupture. The aim of this study was to compare the biomechanical properties of the rat calcaneal tendon (CT), superficial flexor tendon (SFT), and deep flexor tendon (DFT), and to determine the effect of jump training in association with AAS. Animals were separated into four groups: sedentary, trained, AAS-treated sedentary rats (AAS), and AAS-treated and trained animals. Mechanical testing showed that the CT differed from the DFT and SFT, which showed similar mechanical properties. Jump caused the CT to exhibit an extended toe region, an increased resistance to tensional load, and a decreased elastic modulus, characteristics of an elastic tendon capable of storing energy. AAS caused the tendons to be less compliant, and the effects were reinforced by simultaneous training. The DFT was the most affected by training, AAS, and the interaction of both, likely because of its involvement in the toe-off step of jumping, which we suggest is related to the rapid transmission of force as opposed to energy storage. In conclusion, tendons are differently adapted to exercise, but responded equally to AAS, showing reduced flexibility, which is suggested to increase the risk of tendon rupture in AAS consumers.216E91E99Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)FAPESP [06/50986-6

Natação e aspectos morfológicos do músculo esquelético em processo de reparo após criolesão Swimming and morphology of skeletal muscle repair process after cryoinjury

O objetivo do estudo foi investigar a influência da natação sobre as alterações morfológicas do músculo esquelético em processo de reparo após criolesão. Foram usados 45 ratos divididos em cinco grupos: controle (n=5); sham (n=5), adaptação (n=5), criolesionados e tratados com natação sacrificados após 7, 14 e 21 dias (n=15); criolesionados e sem tratamento aquático sacrificados após 7, 14 e 21 dias (n=15). As sessões de natação foram realizadas 6 vezes por semana com 90 min de duração cada. Ao término do protocolo os animais foram sacrificados e a análise morfológica da área da lesão foi realizada. A análise morfológica semiquantitativa demonstrou que os músculos do grupo controle apresentaram aspecto histológico normal. O grupo sham apresentou edema, mionecrose e infiltrado inflamatório em grau 1. Nos grupos 7, 14 e 21 dias, não existiram diferenças estatisticamente significativas nas 4 etapas de remodelamento tecidual avaliadas (infiltrado inflamatório, edema, necrose e fibras musculares imaturas) entre os grupos lesionados quando comparados aos grupos com lesão e tratamento aquático. Em conclusão, foi possível verificar que a natação não causou alterações morfológicas durante o reparo do músculo esquelético após criolesão.<br>The aim of study was investigate the influence of swimming on the morphological changes in skeletal muscle repair process following cryoinjury. There were used 45 rats divided into 5 groups: control (n=5), sham (n=5), adaptation (n=5), cryolesioned treated with swimming and sacrificed after 7, 14 and 21 days (n=15), untreated and cryolesioned sacrificed after 7, 14, and 21 days (n=15). Animals swan for 90 min/ each session and 6 times a week. At the end of the protocol, the animals were sacrificed and morphological analysis of the lesion area was performed. The semi-quantitative morphological analysis showed that the muscles in the control group exhibited normal histological aspects while the sham group exhibited edema, myonecrosis and inflammatory infiltrate grade 1. In groups 7, 14, and 21 days, the results indicated that there were no statistically significant differences in four stages of tissue remodeling evaluated (inflammatory infiltration, edema, necrosis, and immature muscle fibers) between the injured groups compared to groups with lesion and treated with swimming. In conclusion, it was verified that swimming did not alter morphological aspects of skeletal muscle during the repair process following cryoinjury