Proteomics-Based Identification of the Molecular Signatures of Liver Tissues from Aged Rats following Eight Weeks of Medium-Intensity Exercise.

Fanghui Li,Yanying Liu,Tao Li

doi:10.1155/2016/3269405

Abstract

Physical activity has emerged as a powerful intervention that promotes healthy aging by maintaining the functional capacity of critical organ systems. Here, by combining functional and proteomics analyses, we examined how hepatic phenotypes might respond to exercise treatment in aged rats. 16 male aged (20 months old) SD rats were divided into exercise and parallel control groups at random; the exercise group had 8 weeks of treadmill training with medium intensity. Whole protein samples of the liver were extracted from both groups and separated by two-dimensional gel electrophoresis. Alternatively objective protein spots with >2-fold difference in expression were selected for enzymological extraction and MS/MS identification. Results show increased activity of the manganese superoxide dismutase and elevated glutathione levels in the livers of exercise-treated animals, but malondialdehyde contents obviously decreased in the liver of the exercise group. Proteomics-based identification of differentially expressed proteins provided an integrated view of the metabolic adaptations occurring in the liver proteome during exercise, which significantly altered the expression of several proteins involved in key liver metabolic pathways including mitochondrial sulfur, glycolysis, methionine, and protein metabolism. These findings indicate that exercise may be beneficial to aged rats through modulation of hepatic protein expression profiles.

Highlights

Sedentary habits are associated with low levels of physical fitness and a high risk of mortality [1], whereas physical activity has emerged as a powerful intervention that promotes successful aging by maintaining general physical fitness [2]
Liver weight and liver weight/body weight ratio were higher for the livers of EXE animals than for those of the CON group (P < 0.05)
The liver is the primary organ required for processing of nutrients, hormones, and drugs; to evaluate exercise-dependent antiaging effects and adaptive alterations in the proteome of the livers of aged rats after 8 weeks of moderate-intensity training exercise, total liver tissue extracts from sedentary aged rats (22 months, control) and aged rats that were provided exercise training were resolved by 2DGE. 2DGE with medium-range immobilized pH gradient (IPG) revealed 3839 protein spots in the liver that were matched among all rats

Summary

Introduction

Sedentary habits are associated with low levels of physical fitness and a high risk of mortality [1], whereas physical activity has emerged as a powerful intervention that promotes successful aging by maintaining general physical fitness [2]. Exercise-induced oxygen consumption increases associated with energy metabolism adaptation might be involved in physical fitness [3]. The first direct evidence of this was provided by Davies et al [4] through the demonstration that high-intensity exercise enhances reactive oxygen species (ROS) production. High concentrations of ROS can damage proteins, lipids, and nucleic acids, further evidence suggests that exercise promotes the formation of ROS, which participate in redox regulation. Moderate concentrations of ROS function as regulatory mediators to reestablish “redox homeostasis” in signaling processes [5, 6]. In this context, exercise-induced ROS may be involved in the establishment of physical fitness [7]

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Results

Conclusion