The purpose of this study was to verify the effects of short periods of exercise of different intensity on lymphocyte function and cytokines. Thirty Wistar rats, 2 months old, were used. They were divided into five groups of six rats: a sedentary control group; a group exercised for 5 minutes at low intensity (5 L); a group exercised for 15 minutes at low intensity (15 L); and groups exercised at moderate intensity (additional load of 5 % of body weight) for 5 minutes (5 M) or for 15 minutes (15 M). The parameters measured were: total leukocytes, neutrophils, lymphocytes, monocytes, lymphocytes from lymph nodes, serum cytokines (IL-2, IL-6 and TNF-alpha), lymphocyte mitochondrial transmembrane potential, viability and DNA fragmentation. ANOVA two way followed by Tukey's post hoc test (p

OBJECTIVE:To analyze the effects of exhausting long‐duration physical exercise (swimming) sessions of different durations and intensities on the number and phagocytic capacity of macrophages and neutrophils in sedentary rats.INTRODUCTION:Exercise intensity, duration and frequency are important factors in determining immune response to physical effort. Thus, the effects of exhausting long‐duration exercise are unclear.METHODS:Wistar rats were divided into two groups: an untreated group (macrophage study) and oyster glycogen‐treated rats (neutrophil study). In each group, the animals were subdivided into five groups (10 rats per group): unexercised controls, an unadapted low‐intensity exercise group, an unadapted moderate‐intensity exercise group, a preadapted low‐intensity exercise group and a preadapted moderate‐intensity exercise group. All exercises were performed to exhaustion, and preadaptation consisted of 5, 15, 30 and 45 min sessions.RESULTS:Macrophage study: the number of peritoneal macrophages significantly decreased (9.22 ± 1.78 × 106) after unadapted exercise but increased (21.50 ± 0.63 × 106) after preadapted low‐intensity exercise, with no changes in the moderate‐intensity exercise group. Phagocytic capacity, however, increased by more than 80% in all exercise groups (low/moderate, unadapted/preadapted). Neutrophil study: the number of peritoneal neutrophils significantly decreased after unadapted (29.20 ± 3.34 × 106) and preadapted (50.00 ± 3.53 × 106) low‐intensity exercise but increased after unadapted (127.60 ± 5.14 × 106) and preadapted (221.80 ± 14.85 × 106) moderate exercise. Neutrophil phagocytic capacity decreased by 63% after unadapted moderate exercise but increased by 90% after corresponding preadapted sessions, with no changes in the low‐intensity exercise groups.CONCLUSION:Neutrophils and macrophages of sedentary rats respond differently to exercise‐induced stress. Adaptation sessions reduce exercise‐induced stress on the immune system.

A intensidade, volume, modalidade de exercício, assim como o nível de aptidão e fatores nutricionais podem alterar a reposta imunológica. O objetivo deste estudo foi avaliar o efeito da suplementação crônica de farelo de aveia (fonte de fibras solúveis) sobre as células do sistema imunológico em ratos treinados, frente a um teste de exaustão. Foram utilizados ratos Wistar, + dois meses, peso + 200g, divididos em três grupos (n = 9, cada um): 1) controle sedentário (C); 2) treinado oito semanas submetido ao teste de exaustão (EX); e 3) treinado oito semanas submetido ao teste de exaustão com suplementação de 30% de farelo de aveia (EXA). O treinamento consistiu de 60 minutos de natação diários, cinco dias por semana durante oito semanas. As análises realizadas foram: contagem total de leucócitos, linfócitos dos linfonodos mesentéricos, macrófagos peritoneais e capacidade fagocitária de macrófagos peritoneais. Aplicou-se o teste estatístico ANOVA two way, seguido do post hoc de Tukey com p ≤ 0,05. O grupo EX apresentou leucocitose quando comparado com o controle, o que não ocorreu no grupo EXA, porém, na comparação entre os grupos exercitados EXA, mostrou menor leucocitose em relação a EX. Não houve alteração significativa nos linfócitos teciduais em nenhum dos grupos exercitados. Tanto o número de macrófagos peritoneais como a capacidade fagocitária desta célula foram maiores nos grupos exercitados. Porém, no grupo suplementado a capacidade fagocitária foi maior em relação ao grupo exaustão sem farelo de aveia. A suplementação de fibras solúveis demonstrou resultados benéficos com relação às alterações imunológicas induzidas pelo exercício extenuante, além de aumentar a capacidade fagocitária de macrófagos peritoniais em ratos treinados durante oito semanas submetidos ao teste de exaustão.Palavras-chave: exercício físico, sistema imune, fibras solúveis, capacidade fagocitária. ABSTRACTExercise modality, volume, intensity, as well as physical fitness and nutritional factors may modulate the immune response. The purpose of this investigation was to verify the effects of chronic oat bran supplementation on immune cells in trained rats submitted to an extenuating test. Wistar rats (two months old), +200g weight, divided into three groups (n = 9, per group) were used: 1) a sedentary control (C) 2) trained for eight weeks submitted to an exhaustion test (EX), and 3) trained for eight weeks submitted to an exhaustion test with 30% oat bran supplementation (EXA). Training consisted of 60 daily minutes of swimming, five days a week, during eight weeks. The analyses conducted were: total leukocytes, lymphocytes from lymph nodes, peritoneal macrophages and peritoneal macrophages phagocytic capacity. Statistical analyses were done by the two-way ANOVA test, followed by Tukey's post hoc test (p ≤ 0.05). EX group presented leukocytosis when compared to control; however, EXA group did not. In exercised group, comparison with EXA has shown lower leukocytosis in relation to EX. No significant alteration was observed for tissue ly...