Swimming Exercise Alleviated Insulin Resistance by Regulating Tripartite Motif Family Protein 72 Expression and AKT Signal Pathway in Sprague-Dawley Rats Fed with High-Fat Diet.

Jie Qi,Cailing Ren,Jian Fu,Bo Yang,Jun Zhang

doi:10.1155/2016/1564386

Abstract

We aimed to investigate whether swimming exercise could improve insulin resistance (IR) by regulating tripartite motif family protein 72 (TRIM72) expression and AKT signal pathway in rats fed with high-fat diet. Five-week-old rats were classified into 3 groups: standard diet as control (CON), high-fat diet (HFD), and HFD plus swimming exercise (Ex-HFD). After 8 weeks, glucose infusion rate (GIR), markers of oxidative stress, mRNA and protein expression of TRIM72, protein of IRS, p-AKTSer473, and AKT were determined in quadriceps muscles. Compared with HFD, the GIR, muscle SOD, and GSH-Px were significantly increased (p < 0.05, resp.), whereas muscle MDA and 8-OHdG levels were significantly decreased (p < 0.05 and p < 0.01) in Ex-HFD. Expression levels of TRIM72 mRNA and protein in muscles were significantly reduced (p < 0.05 and p < 0.01), whereas protein expression levels of IRS-1, p-AKTSer473, and AKT were significantly increased in Ex-HFD compared with HFD (p < 0.01, p < 0.01, and p < 0.05). These results suggest that an 8-week swimming exercise improves HFD-induced insulin resistance maybe through a reduction of TRIM72 in skeletal muscle and enhancement of AKT signal transduction.

Highlights

Insulin resistance (IR) is the important pathophysiological basis of diseases such as type 2 diabetes mellitus (T2DM), hypertension, hyperlipidemia, and obesity [1, 2]
Euglycemic clamp was firstly performed; the results showed that the glucose infusion rate (GIR) of group high-fat diet (HFD) considerably decreased (p < 0.01) compared with that in group CON, while the GIR in rats of group Ex-HFD significantly increased (p < 0.01) compared with that in group HFD (Figure 2(a))
The Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) was greatly decreased (p < 0.01) compared with that in group HFD (Figure 2(d)). These results proved that the animal model prepared using high-fat diet is suitable for the current study, and an 8-week swimming exercise can improve IR in rats induced by high-fat diet

Summary

Introduction

Insulin resistance (IR) is the important pathophysiological basis of diseases such as type 2 diabetes mellitus (T2DM), hypertension, hyperlipidemia, and obesity [1, 2]. During IR pathogenesis, abnormally high TRIM72 expression in skeletal muscles was higher than that in other organs, which was the important originating mechanism leading to systemic metabolic disorders [10,11,12]; it suggests that TRIM72 may be a specific muscle factor in early stage of IR pathological genesis. TRIM72 expression is increased under the condition of oxidative stress induced with high-fat diet [5]. These findings suggest that regulation of TRIM72 to AKT signal pathway is involved in the IR pathogenesis

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