Made available in DSpace on 2016-06-02T19:22:50Z (GMT). No. of bitstreams: 1 2009.pdf: 1332211 bytes, checksum: 8cbbbf935b4f4e81409c0c7f26786e9a (MD5) Previous issue date: 2008-08-11 / Universidade Federal de Sao Carlos / Androgenic-anabolic steroids have been used both for performance improvement and aesthetic reasons. It is well know that high doses of AAS can raise serious adverse effects such as skeletal muscle injuries including increase in the rate of muscle strains/ruptures. The aim of this study was to investigate VEGF mRNA expression in the rat soleus muscle after jumping training associated with androgenic-anabolic steroids (AAS) administration. Wistar rats were grouped into: sedentary (S); trained without AAS (T); nandrolone decanoate (ND)-treated sedentary (AAS); and trained with AAS (AAST). The trained groups have carried out jumps in water at 32°C.: 4 series of 10 jumps each, with a 30-second interval among series, for 7 weeks, with 50- 80% overload of the animal corporal mass. The AAS (Decadurabolin® - 5mg/kg) was injected via subcutaneous in animal back twice a week. Real-time PCR analyses have shown that training significantly increased VEGF mRNA expression in comparison with the S, AAS groups. When training exercise was associated with nandrolone decanoate, the VEGF mRNA expression was inhibit compared with T group. The inhibited expression of VEGF by AAS administration could cause diminished angiogenesis in skeletal muscle. These results suggest that the AAS may be strongly prejudicial to muscle remodeling and performance. / Muitos estudos vêm mostrando os efeitos nocivos para o organismo do abuso de esteróides anabólicos androgênicos (EAA) por atletas e freqüentadores de academia. Entretanto há poucas pesquisas relatando os efeitos prejudiciais dessas substâncias no músculo esquelético. O objetivo desse trabalho foi analisar a expressão do fator de crescimento de endotélio vascular (VEGF) no músculo sóleo de ratos submetidos ao tratamento com EAA e ao exercício de carga. Os animais foram divididos em quatro grupos: S (sedentário controle), T (treinado controle), EAA (sedentário com administração de decanoato de nandrolona) e EAAT (treinado com administração de decanoato de nandrolona). O treinamento foi constituído por saltos em meio líquido à 32°C: 4 séries de 10 saltos cada, com intervalo de 30 segundos entre as séries, em 5 dias da semana, durante 7 semanas, com carga variando de 50 80% da massa corporal do animal. O decanoato de nandrolona (Decadurabolin® - mg/kg) foi injetado via subcutânea no dorso dos animais, duas vezes por semana. A análise da expressão de mRNA de VEGF, por PCR em tempo real mostrou que no grupo que treinou e que não recebeu a injeção de EAA houve aumento significante na expressão desse fator em relação aos grupos que não treinaram (S e EAA). Por outro lado, quando o treino foi associado com a administração de EAA houve inibição da expressão de VEGF em relação ao grupo treinado controle. VEGF é um fator chave na indução da angiogênese, processo de formação de novos vasos sangüíneos a partir de vasos pré-existentes e essa é uma das primeiras adaptações do músculo ao exercício. Em conclusão a diminuição da expressão de VEGF com o uso de EAA poderia provocar uma redução na formação desses novos vasos, promovendo possivelmente uma redução na performance.

Sehnenverletzungen machen ca. 30 % der muskuloskelettalen Beschwerden aus. Repetitive Überlastung wird häufig als Ursache diskutiert. Dabei entstehende strukturelle Schäden können die Kapazität der Sehne, mechanische Belastung zu tolerieren, reduzieren. Das exzentrische Protokoll nach Alfredson sowie das „heavy slow resistance training“ sind häufig genutzte Formen der Trainingstherapie. Jedoch zeigen diese Protokolle bisher kaum Nachweise für strukturelle Anpassung. Eine trainingsinduzierte Zunahme der Sehnensteifigkeit könnte die Sehne widerstandsfähiger machen und vor Überlastung schützen, da die Beanspruchung (Sehnendehnung) bei gegebener Belastung reduziert wird. Bei gesunden Probanden führte das „high-loading“ Protokoll, das mit einer hohen Dehnungsmagnitude arbeitet, ausgelöst durch ca. 90 % der maximal willkürlichen Kontraktionskraft der Plantarflexoren, sowie einer Dauer von 3 Sek., zu positiven strukturellen Anpassungen. Die vorliegende Arbeit zeigt erstmals, dass sich tendinopathische Achillessehnen bei ausreichend hohem mechanischen Stimulus ähnlich gesunden Sehnen anpassen. Im Vergleich zum exzentrischen Training sowie passiver Therapie führte nur das high-loading Protokoll zu einer Hypertrophie der Sehne sowie einer Zunahme der Sehnensteifigkeit, während es in allen drei Gruppen gleichermaßen zu klinisch-funktionellen Verbesserungen kam. Das dabei angewandte mobile Trainingsgerät bewies in einer separaten Studie exzellente Reliabilität sowie Effektivität (Kraft/Sprunghöhe). Weiters wurden Asymmetrien zwischen der betroffenen/nicht-betroffenen Seite untersucht. Größtenteils zeigten sich im Vergleich zu Gesunden ähnlich ausgeprägte Asymmetrien. Die Effekte auf diese Asymmetrien durch Training waren eher gering. Eine Reduzierung der Asymmetrien ging nicht notwendigerweise einher mit einer klinisch-funktionellen Verbesserung. Insgesamt liefern die Ergebnisse wichtige Erkenntnisse bezüglich einer neuartigen Behandlungsmethode der Achillestendinopathie, die durch die hervorgerufene Verbesserung von Sehneneigenschaften sowohl für die Rehabilitation als auch Prävention zu empfehlen ist. / Tendon injuries account for approximately 30 % of musculoskeletal consultations. Repetitive overload is identified commonly as initial cause implicating structural impairments. Hence, the capacity of the tendon to tolerate mechanical load might be attenuated. In Achilles tendinopathy, Alfredsons ´eccentric exercise protocol and heavy slow resistance training are frequently applied exercise interventions both leading to clinical and functional improvements. However, evidence for eliciting structural adaptation is lacking. An exercise-induced increase in tendon stiffness might improve the tendon `s capacity to tolerate loading and thus reduce future damage as tendon strain at a given force is reduced. In healthy subjects, the high-loading protocol applying high tendon strain induced by highly intensive muscle contractions (i.e., at 90 % of maximum voluntary isometric contraction) with 3 seconds time-under-tension has led to positive adaptations (i.e., increased cross-sectional area and stiffness). This thesis first provides evidence that tendinopathic Achilles tendons do adapt comparable to healthy tendons given that an adequate mechanical stimulus was applied. High-loading led to tendon hypertrophy and an increase in tendon stiffness compared to eccentric exercise or passive therapy, while clinical/functional improvements have been detected in all the three groups. In a separate trial, the applied mobile training device showed excellent reliability and effectiveness (strength/jump height). Further, inter-limb asymmetries have been investigated showing comparable levels except for vascularization compared to healthy subjects. Therapeutic interventions had only small effects regarding pronounced asymmetry reductions whereas a reduction in asymmetry did not necessarily correlate with an improvement in tendon health. In conclusion, the findings of the present thesis provide valuable evidence for high-loading as a novel exercise treatment in Achilles tendinopathy.