BackgroundThe aim of the present study was to evaluate the protective effect of concurrent exercise in the degree of the insulin resistance in mice fed with a high-fat diet, and assess adiponectin receptors (ADIPOR1 and ADIPOR2) and endosomal adaptor protein APPL1 in different tissues.MethodsTwenty-four mice were randomized into four groups (n = 6): chow standard diet and sedentary (C); chow standard diet and simultaneous exercise training (C-T); fed on a high-fat diet and sedentary (DIO); and fed on a high-fat diet and simultaneous exercise training (DIO-T). Simultaneously to starting high-fat diet feeding, the mice were submitted to a swimming exercise training protocol (2 x 30 minutes, with 5 minutes of interval/day), five days per week, for twelve weeks (90 days). Animals were then euthanized 48 hours after the last exercise training session, and adipose, liver, and skeletal muscle tissue were extracted for an immunoblotting analysis.ResultsIR, IRs, and Akt phosphorylation decreased in the DIO group in the three analyzed tissues. In addition, the DIO group exhibited ADIPOR1 (skeletal muscle and adipose tissue), ADIPOR2 (liver), and APPL1 reduced when compared with the C group. However, it was reverted when exercise training was simultaneously performed. In parallel, ADIPOR1 and 2 and APPL1 protein levels significantly increase in exercised mice.ConclusionsOur findings demonstrate that exercise training performed concomitantly to a high-fat diet reduces the degree of insulin resistance and improves adipoR1-2/APPL1 protein levels in the hepatic, adipose, and skeletal muscle tissue.

This study aimed to compare the effects of three different resistance exercise models on the quadriceps muscle crosssectional area, as well as on mTOR phosphorylation and other pivotal molecules involved in the upstream regulation of mTOR.Twenty-four male Wistar rats were divided into untrained (control), endurance resistance training, strength resistance training, and hypertrophy resistance training (HRT) groups (n=6). After 12 weeks of training, the red portion of the quadriceps was removed for histological and Western blot analyses. The results showed that the quadriceps weight and cross-sectional areas in the exercised groups were higher than those of the untrained rats. However, the HRT group presented better results than the other two experimental groups. This same pattern was observed for mTOR phosphorylation and for the most pivotal molecules involved in the upstream control of mTOR (increase of PKB, 14-3-3, ERK, p38 MAPK, and 4E-BP1 phosphorylation, and reduction of tuberin, sestrin 2, REDD1, and phospho AMPK). In summary, our study showed that HRT leads to high levels of mTOR phosphorylation as well as of other proteins involved in the upstream regulation of mTOR.

The present study investigated the effects of running at 0.8 or 1.2 km/h on inflammatory proteins (i.e., protein levels of TNF-α, IL-1β, and NF-κB) and metabolic proteins (i.e., protein levels of SIRT-1 and PGC-1α, and AMPK phosphorylation) in quadriceps of rats. Male Wistar rats at 3 (young) and 18 months (middle-aged rats) of age were divided into nonexercised (NE) and exercised at 0.8 or 1.2 km/h. The rats were trained on treadmill, 50 min per day, 5 days per week, during 8 weeks. Forty-eight hours after the last training session, muscles were removed, homogenized, and analyzed using biochemical and western blot techniques. Our results showed that: (a) running at 0.8 km/h decreased the inflammatory proteins and increased the metabolic proteins compared with NE rats; (b) these responses were lower for the inflammatory proteins and higher for the metabolic proteins in young rats compared with middle-aged rats; (c) running at 1.2 km/h decreased the inflammatory proteins and increased the metabolic proteins compared with 0.8 km/h; (d) these responses were similar between young and middle-aged rats when trained at 1.2 km. In summary, the age-related increases in inflammatory proteins, and the age-related declines in metabolic proteins can be reversed and largely improved by treadmill training.

mone-sensitive lipase (HSL) have the capacity for TG degradation by cleaving the ester bond, governing the lipolysis pathway in adipose tissue [ 6 ]. Adipose tissue lipolysis has received much attention over the past 10 years because of its altered regulation in obesity. Studies have suggested that obesity is associated with changes in gene expression in adipocytes with diff erent metabolic pathways and in diff erent organs and tissues, resulting in various metabolic actions and molecular signals [ 7 ] , and is closely associated with the low-grade chronic infl ammatory response [ 2 ]. These biochemical and molecular changes involve the participation of a number of molecules as transcription factors, infl ammatory mediators, and the formation of reactive oxygen species (ROS). ROS are chemically reactive molecules that are produced during normal metabolism of oxygen and play important roles in cell signaling and Authors J. M.

Our results indicate that ROS induced by acute exercise play the important role of activating eNOS, a process apparently mediated by Akt and AMPK.

Obesity is associated with myocardial insulin resistance and impairment of the mammalian target of rapamycin (mTOR) signaling pathway. The activation of the mTOR cascade by exercise has been largely shown in skeletal muscle, but insufficiently analyzed in myocardial tissue. In addition, little is known regarding the mTOR upstream molecules in the hearts of obese animals and even less about the role of exercise in this process. Thus, the present study was aimed to evaluate the effects of physical exercise on P38 Mitogen-Activated Protein Kinase (P38MAPK) phosphorylation and the REDD1 (regulated in development and DNA damage responses 1) and 14-3-3 protein levels in the myocardium of diet-induced obesity (DIO) rats. After achievement of DIO and insulin resistance, Wistar rats were divided in 2 groups: sedentary obese rats and obese rats performed treadmill running (50-min/day, 5 days per week velocity of 1.0 km/h for 2 months). Forty-eight hours after the final physical exercise, the rats were killed, and the myocardial tissue was removed for Western blot analysis. DIO increased the REDD1 protein levels and reduced the 14-3-3 protein levels and P38MAPK, mTOR, P70S6k (p70 ribosomal S6 protein kinase), and 4EBP1 (4E-binding protein-1) phosphorylation. Interestingly, physical exercise reduced the REDD1 protein levels and increased the 14-3-3 protein levels and P38MAPK, mTOR, P70S6k, and 4EBP1 phosphorylation. Moreover, exercise increased the REDD1/14-3-3 association in the heart. Our results indicate that the phospho-P38MAPK, REDD1, and 14-3-3 protein levels were reduced in the myocardium of obese rats and that physical exercise increased the protein levels of these molecules.

Our study allows concluding that the reduction in SREBP-1c protein levels is associated with steatosis reversion induced by exercise training.

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