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Previous issue date: 2015-07-14 / Telomeres are composed of complex deoxyribonucleic acid and proteins located at the ends of chromosomes, formed by a short sequence of nitrogenous bases (5'-TTAGGGn -3 ') repeated several times. Are connected to a multiprotein complex called "shelterin" consists of six proteins (TRF1, TRF2, POT1, TIN2, RAP1 and TPP1) which maintains telomere homeostasis, preventing degradation. Telomeres are affected by the DNA polymerase inability fully replicate the tape 5' end of the chromosome. The results of such failure are successors shortenings with each cell division, which leads to extremely short telomeres at the end of cell division, resulting in cell senescence. Therefore telomeres are considered a potential biomarker of aging at the cellular level. The shortening of telomeres has been associated with an increased risk of developing age-related diseases such as diabetes, cardiovascular disease and obesity. In contrast, it is believed that physical exercise can attenuate the shortening rate of telomeres, even in the elderly. However, it is possible that there is a 'dose' ideal of physical exercise that can enhance this beneficial effect. The objective of this study was to analyze and compare the effects of aerobic training intensity swimming conducted in two intensity domains (high and low) on the expression of genes encoding the protective telomeric proteins (trf1 and trf2), associated proteins cellular senescence (p53 and Chek2), in addition to measuring telomere length in gastrocnemius and myocardium old mice. Sixteen animals were divided into four groups: two groups submitted to twelve weeks of physical training of swimming at low intensity (BI) and high intensity (AI) and two who remained sedentary for the same period, with a group of young animals (CONTj) and elderly animals (CONTi). Training consisted of swimming exercise three times a week, 20 minutes per session for the group AI and 40 minutes for BI with load corresponding to 3% body weight (%PC) (BI) and 6%PC (AI). An incremental test for functional evaluation was performed every four weeks to measure the maximum load (Gm??x). After the training period, animals were sacrificed for removal of tissue samples for analysis of genes expression related to telomeres. The results suggest that high intensity exercise is "teloprotetor" in the gastrocnemius tissue, since telomere length of the elderly animals did not differ from each other, however, the animals in this group (AI) had a lower expression of genes of proteins protective (trf1 and trf2) and cellular senescence (p53). These results suggest that the intensity at which the exercise is performed interfere with telomere length and that this response is tissue dependent, since the same results were not observed in cardiac tissue of animals. / Tel??meros s??o complexos compostos por ??cido desoxirribonucleico e prote??nas, localizados nas extremidades dos cromossomos, formados por uma pequena sequ??ncia de bases nitrogenadas (5???-TTAGGGn -3???) repetida diversas vezes. Encontram-se ligados a um complexo multiprot??ico denominado ???shelterin??? composto por seis prote??nas (TRF1, TRF2, POT1, TIN2, RAP1 e TPP1) que mant??m a homeostase telom??rica, prevenindo sua degrada????o. Os tel??meros s??o afetados pela incapacidade da DNA polimerase replicar completamente o final da fita 5??? do cromossomo. Os resultados de tal falha s??o sucess??veis encurtamentos a cada divis??o celular, o que leva ?? tel??meros extremamente curtos ao t??rmino das divis??es celulares, resultando na senesc??ncia celular. Sendo assim, considerados um potencial biomarcador do envelhecimento a n??vel celular. O encurtamento dos tel??meros tem sido associado a um maior risco de desenvolvimento de doen??as associadas ao envelhecimento, tais como, diabetes mellitus, doen??as cardiovasculares e obesidade. Em contrapartida, acredita-se que o exerc??cio f??sico possa atenuar a taxa de encurtamento dos tel??meros, mesmo em indiv??duos idosos. Contudo, ?? poss??vel que exista uma ???dose??? ideal de exerc??cio f??sico que possa potencializar este efeito ben??fico. Assim, o objetivo do presente estudo foi analisar e comparar os efeitos do treinamento aer??bio de nata????o realizado em dois dom??nios de intensidade (alta e baixa) sobre a express??o dos genes que codificam as prote??nas de prote????o telom??rica (trf1 e trf2), prote??nas associadas ?? senesc??ncia celular (p53 e Chek2), al??m de mensurar o comprimento do tel??mero no gastrocn??mio e no mioc??rdio de camundongos idosos. Dezesseis animais foram divididos em quatro grupos: dois grupos submetidos a doze semanas de treinamento f??sico de nata????o em baixa intensidade (BI) ou alta intensidade (AI) e dois que permaneceram sedent??rios pelo mesmo per??odo, sendo um grupo de animais jovens (CONTj) e um de animais idosos (CONTi). O treinamento consistiu do exerc??cio de nata????o, tr??s vezes por semana, 20 minutos por sess??o para o grupo AI e 40 minutos para o BI, com carga correspondente a 3% do peso corporal (%PC) (BI) e 6%PC (AI). Um teste incremental para avalia????o funcional fora realizado a cada quatro semanas para mensura????o da carga m??xima (Gm??x). Ap??s o t??rmino do per??odo de treinamento, os animais foram sacrificados para retirada de amostras de tecido para an??lise da express??o dos genes relacionados aos tel??meros. Os resultados obtidos sugerem que o exerc??cio de alta intensidade seja ???teloprotetor??? no tecido gastrocn??mio, uma vez que o comprimento do tel??mero dos animais idosos n??o diferiu entre si, embora, os animais desse grupo (AI) apresentaram uma menor express??o dos genes das prote??nas protetoras (trf1 e trf2) e da senesc??ncia celular (p53). Esses resultados sugerem que a intensidade na qual o exerc??cio ?? realizado interfere no comprimento dos tel??meros e que tal resposta ?? tecido dependente, uma vez que os mesmos resultados n??o foram observados no tecido card??aco dos animais.
| Identifer | oai:union.ndltd.org:IBICT/oai:bdtd.ucb.br:tede/2042 |
| Date | 14 July 2015 |
| Creators | Cunha, Verusca Najara de Carvalho |
| Contributors | Sim??es, Herbert Gustavo, Andrade, Ros??ngela Vieira de |
| Publisher | Universidade Cat??lica de Bras??lia, Programa Strictu Sensu em Educa????o F??sica, UCB, Brasil, Escola de Sa??de e Medicina |
| Source Sets | IBICT Brazilian ETDs |
| Language | Portuguese |
| Detected Language | Portuguese |
| Type | info:eu-repo/semantics/publishedVersion, info:eu-repo/semantics/doctoralThesis |
| Format | application/pdf |
| Source | reponame:Biblioteca Digital de Teses e Dissertações da UCB, instname:Universidade Católica de Brasília, instacron:UCB |
| Rights | info:eu-repo/semantics/openAccess |
| Relation | 6095716513072507778, 500, 500, 600, 3870802503144686128, 5178284805913411594 |
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