Exercício na prevenção do diabetes mellitus em modelo experimental com ratos
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Data
2008-04-25
Autores
Ribeiro, Carla [UNESP]
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Editor
Universidade Estadual Paulista (Unesp)
Resumo
O exercício tem sido recomendado na prevenção do diabetes mellitus não insulino dependente (NIDDM), mas os mecanismos envolvidos nessa intervenção ainda não são bem conhecidos. Modelos experimentais oferecem oportunidade para o estudo dessa questão. Ratos induzidos com streptozotocina no período neonatal têm sido empregados como modelo de NIDDM, porém, pouco se sabe sobre o modelo de diabetes neonatal induzido por aloxana. Na busca de um modelo experimental adequado a estudos sobre o papel do exercício na prevenção do diabetes, o presente estudo foi delineado para analisar os efeitos do treinamento físico sobre a evolução do quadro diabético em ratos submetidos à aplicação neonatal com aloxana. Para tanto, ratos recém nascidos (6 dias) receberam aloxana (250 mg/kg de peso corporal) via intraperitoneal. Como controles foram utilizados ratos injetados com veículo (tampão citrato). Metade dos animais foi submetida ao treinamento por natação 1hora/ dia, 5 dias/semana com sobrecarga de 5% do peso corporal, a partir do desmame. Após o desmame ( 28 dias), não foram observadas diferenças entre os grupos em relação à glicemia e a insulinemia de jejum. Aos 60 dias de idade, a glicemia de jejum foi menor no grupo que recebeu aloxana submetido ao treinamento em relação ao sedentário correspondente. A tolerância à glicose dos ratos que receberam aloxana mostrou-se menor do que a dos controles, tanto aos 28 quanto aos 60 dias, visto que a área sob a curva glicêmica durante o teste de tolerância à glicose oral (GTTo) foi maior nos primeiros (aloxana) que nos últimos (controle). O exercício físico atenuou a alteração provocada pela aloxana. Com relação a sensibilidade à insulina (HOMA), não foi encontrada diferença entre os grupos tanto aos 28 quanto aos 60 dias.
Physical exercises have been recommended in the prevention of non-insulin dependent diabetes mellitus (NIDDM), but the mechanisms involved in this intervention are not yet fully understood. Experimental models offer the opportunity for the study of this matter. Induced rats with streptozotocin in the neonatal period have been used as model of NIDDM, however, not much is known about the model of neonatal diabetes induced by alloxan. In search of an appropriate experimental model for studies on the role of exercise in the prevention of diabetes, the present study was designed to analyse the effects of physical exercise on the development of the diabetic condition in rats submitted to neonatal alloxan aplication. For this, newly born rats (6 days old) received alloxan intraperitoneally (A= 250 mg/kg of body weight). Rats injected with vehicle (citrate buffer) were used as controls (C). After weaning, half of the animals was submitted to 1 hour/day, 5 days/week swimming, with an overload equivalent to 5% of their body weight. After weaning (28 days), no significant differences were found among the groups in relation to fasting glycemia and insulinaemia. At 60 days old, the fasting glycemia was lower in the alloxan group submitted to training than in the correspondent sedentary group. The glucose tolerance of the alloxan rats showed to be reduced in comparison to, both at 28 and 60 days old, since that the area under the glicemic curve during an oral glucose tolerance test (GTTo) was higher in the alloxan than in the controls. The exercise atenuated the changes caused by alloxan. No difference was found among the groups both at 28 and 60 days old in the insulin sensitivity (HOMA index). However, a slight reduction was observed in the values of the trained groups suggesting a increased insulin sensitivity in the animals.
Physical exercises have been recommended in the prevention of non-insulin dependent diabetes mellitus (NIDDM), but the mechanisms involved in this intervention are not yet fully understood. Experimental models offer the opportunity for the study of this matter. Induced rats with streptozotocin in the neonatal period have been used as model of NIDDM, however, not much is known about the model of neonatal diabetes induced by alloxan. In search of an appropriate experimental model for studies on the role of exercise in the prevention of diabetes, the present study was designed to analyse the effects of physical exercise on the development of the diabetic condition in rats submitted to neonatal alloxan aplication. For this, newly born rats (6 days old) received alloxan intraperitoneally (A= 250 mg/kg of body weight). Rats injected with vehicle (citrate buffer) were used as controls (C). After weaning, half of the animals was submitted to 1 hour/day, 5 days/week swimming, with an overload equivalent to 5% of their body weight. After weaning (28 days), no significant differences were found among the groups in relation to fasting glycemia and insulinaemia. At 60 days old, the fasting glycemia was lower in the alloxan group submitted to training than in the correspondent sedentary group. The glucose tolerance of the alloxan rats showed to be reduced in comparison to, both at 28 and 60 days old, since that the area under the glicemic curve during an oral glucose tolerance test (GTTo) was higher in the alloxan than in the controls. The exercise atenuated the changes caused by alloxan. No difference was found among the groups both at 28 and 60 days old in the insulin sensitivity (HOMA index). However, a slight reduction was observed in the values of the trained groups suggesting a increased insulin sensitivity in the animals.
Descrição
Palavras-chave
Medicina esportiva, Aloxana, Ratos neonatos, Diabetes, Diabetes mellitus, Exercício físico, Neonatal rats, Physical exercise
Como citar
RIBEIRO, Carla. Exercício na prevenção do diabetes mellitus em modelo experimental com ratos. 2008. 56 f. Dissertação (mestrado) - Universidade Estadual Paulista, Instituto de Biociências de Rio Claro, 2008.