A análise dos dados foi realizada através do software SigmaStat (versão 3.1, SigmaStat, SYSTAT, Point Richmond, CA). A média aritmética e o erro padrão da média (EPM) foram calculados para todas as variáveis estudadas. A primeira observação indica que os resultados apresentam distribuição normal, após realização do teste de Kolmogorov-Smirnov e que não há diferença na variância entre as amostras dos grupos (heterocedasticidade), após realização do teste de igualdade de variância. Após a período experimental os valores das diferentes análises foram analisados pela Analise de variância (ANOVA) a 1 fator. Quando o valor de F foi significantemente detectado pela ANOVA a 1 fator, teste post-hoc de Holm-Sidak foi aplicado para a múltipla comparação entre as médias dos grupos avaliados. O nível de significância utilizado em todas as análises foi inferior a 5%, ou seja, p<0,05.
24 5.Resultados
Os resultados desta tese estão apresentados na forma de 3 trabalhos científicos:
1. Exhaustive exercise causes an anti-inflammatory effect in skeletal muscle and a pro- inflammatory effect in adipose tissue in rats. José C Rosa Neto, Fábio S Lira, Lila M Oyama, Nelo E Zanchi, Alex S Yamashita, Miguel l Batista Jr, Cláudia M Oller do Nascimento, Marília Seelaender. Publicado no European Journal Applied Physiology, 2009.
2. Acute exhaustive exercise regulated protein levels of IL-2, IL-4 and Myod in skeletal muscle, but not in adipose tissue in rats. José C Rosa Neto, Fábio S Lira, Alex S Yamashita, Nelo E Zanchi, Lila M Oyama, Ronaldo V T dos Santos, Marco Túlio de Mello, Sérgio Tufik, Ana R Dâmaso, Marília Seelaender, Cláudia M Oller do Nascimento (submetido).
3. Exhaustive exercise increased inflammatory response via Toll Like Receptor 4 and NF-kBp65 pathway in adipose tissue in rats. José C Rosa Neto, Fábio S Lira, Ricardo Eguchi, Gustavo D Pimentel, Daniel P Venâncio, Cláudio A Cunha, Lila M Oyama, Marco Túlio de Mello, Sérgio Tufik, Ana R Dâmaso, Marília Seelaender, Cláudia M Oller do Nascimento (submetido).
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Exhaustive exercise causes an anti-inflammatory effect in skeletal muscle and a pro-inflammatory effect in adipose tissue in rats
José C Rosa Neto1, Fábio S Lira1,2,Lila M Oyama1, Nelo E Zanchi3, Alex S Yamashita2, Miguel L Batista
Jr2, Cláudia M Oller do Nascimento1, Marília Seelaender2 .
1Department of Physiology of Nutrition – Federal University of São Paulo – São Paulo, Brazil. 2Molecular Cell Biology Study Group – Department of Cell Biology and Development – Institute o
Biomedical Sciences I - University of São Paulo, Brazil. 3School of Physical Education and Sports -
University of São Paulo – São Paulo, Brazil. Corresponding Author:
Cláudia Maria Oller do Nascimento
Department of Physiology of Nutrition – Federal University of São Paulo – São Paulo, Brazil. Address: Rua Botucatu 862, 2º andar, São Paulo, SP, Brazil. CEP: 04023-060.
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Abstract
It is well known that exhaustive exercise increases serum and skeletal muscle IL-6 concentrations. However, the effect of exhaustive exercise on the concentrations of other cytokines in the muscle and in the adipose tissue is controversial. The purpose of this study was to evaluate the effect of exhaustive exercise on mRNA and protein expression of IL-10, TNF-α and IL-6 in different types of skeletal muscle (EDL, soleus) and in two different depots of white adipose tissue (mesenteric - MEAT and retroperitoneal - RPAT). Rats were killed by decapitation immediately (E0 group, n=6), 2 (E2 group, n=6) and 6 (E6 group, n=6) hours after the exhaustion protocol, which consisted of running on a treadmill (approximately 70% VO2max for fifty minutes and then subsequently at an elevated rate that increased at one m/min every
minute, until exhaustion). The control group (C group, n=6) was not subjected to exercise. Cytokine protein expression increased in EDL, soleus, MEAT and RPAT from all exercised groups, as detected by ELISA. EDL IL-10 and TNF-α expression was higher than that of the soleus. The IL-10/TNF-α ratio was increased in the skeletal muscle, especially in EDL, but it was found to be decreased in the adipose tissue. These results show that exhaustive exercise presents a different effect depending on the tissue which is analysed: in the muscle, it induces an anti-inflammatory effect, especially in type 2 fibres, while the pro- inflammatory effect prevails in adipose tissue, possibly contributing to increased lipolysis to provide energy for the exercising muscle.
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Introduction:
Exercise represents a physical stress that challenges homeostasis (Mastorakos and Pavlatou 2005). Therefore, a single bout of exercise is a mild physical stressor that exerts an array of effects on immune parameters (Sprenger et al. 1992; Schulz et al. 2004). The body reacts to physical activity as it does during an acute, subclinical inflammatory response to a perceived pathological insult (Bury et al. 1996; Camus et al. 1998).
Most studies in humans indicate that during and following prolonged exercise, plasma cytokine concentrations (e.g., IL-6, IL-10, CSF, MIP, TNF) peak at the end of exercise (Starkie et al. 2000; Suzuki et al. 2003; Chan et al. 2004), with the exception of IL-1ra, which peaks 1-2 hours post-exercise (Ostrowski et al 1999). IL-6 is generally considered to be inflammation-responsive and to induce anti- inflammatory effects (via its actions in stimulating cortisol, secreting IL-10 and IL-1ra, and inhibiting TNF- production) rather than pro-inflammatory effects (Steensberg et al, 2003; Pedersen and Fischer 2007).
During the past few years, it has been demonstrated that the contraction of human and rat skeletal muscle produces and releases IL-6 into the circulatory system (Jonsdottir et al. 2000; Febbraio et al. 2003). Myofibres can, per se, be a source of IL-6 production during exercise (Penkowa et al. 2003; Hiscock et al. 2004). A few studies examined which specific fibre type is involved in IL-6 production under the stimulus of exercise, from which some showed a marked increase in production from type 1 fibres (Plomgaard et al. 2005; Banzet et al. 2005). However, Hiscock et al (2004) reported a higher increase in mRNA and protein expression of IL-6 in type 2 fibres.
Several studies have shown an increase in serum TNF-α concentration after strenuous exercise (Hirose et al. 2004; Zaldivar et al. 2006). However, this concentration increase during exercise is very small compared to the magnitude of increases in IL-6, IL-10 and IL-1ra. It has been shown that skeletal muscle is able to express this protein (Plomgaard et al. 2005; Meador et al. 2008) in a process that is enhanced by resistance exercise (Raue et al. 2007). Plomgaard et al. (2005) demonstrated with immunohistochemistry that TNF-α is only expressed by type 2 fibres in resting human muscle.
Exhaustive exercise is capable of raising the concentration of anti-inflammatory cytokines in serum, such as IL-10 (Ostrowski et al. 1999; Suzuki et al. 2006). The IL-10/TNF-α ratio has been adopted as an indicator of inflammatory status and disease-associated morbidity, with lower values associated with poorer prognoses (Kaur et al. 2006; Leonidou et al. 2007). However, to our knowledge, no study has
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evaluated TNF-α and IL-10 production in different muscle fibre types after strenuous exercise in healthy rats.
The adipose tissue actively secretes various bioactive peptides, termed ―adipokines‖, which act both locally and distally and have autocrine, paracrine, and endocrine effects (Pond 1999). The physiology, metabolism, and function of white adipose tissue vary in a depot-specific manner, as reviewed by Lafontan and Berlan (2003). Therefore, marked differences in gene expression amongst depots are reported both for rodents (Gesta et al. 2006) and humans (Vohl et al. 2004), and cytokine secretion is also heterogeneous (Lafontan et al. 2003). Recently, increases in TNF-α, IL-10 and the IL-
10/TNF-α ratio have been shown in white adipose tissue after a rest period of 24 hours following an endurance exercise training protocol (Lira et al. 2009). However, Gomez-Merino et al (2007) did not find a significant increase in IL-10 from white adipose tissue following endurance training.
The aim of this study was to examine the effects of acute exhaustive exercise on the time course of IL-6, TNF-α, and IL-10 protein expression in rodent soleus and extensor digitorum longus (EDL) muscles, as well as in retroperitoneal and mesenteric white adipose tissue depots.
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MATERIALS AND METHODS: