Eccentric exercise and dietary restriction inhibits M1 macrophage polarization activated by high-fat diet-induced obesity

Abstract

Aims: Obesity induce low-grade inflammation and elicit insulin resistance (IR), exercise training accompanied by a low-fat diet has been prescribed as part of the treatment for managing obesity and IR. The purpose of this study is to evaluate the effect of eccentric exercise accompanied by a low-fat diet on glycolipid metabolism, exercise capacity, and macrophage polarization in obesity-induced IR mice.

Materials and methods: Mice were fed with 60% high fat diet (HFD) for 12 weeks and subsequently treated with eccentric exercise or/and dietary restriction for 8 weeks. Related biochemical index were examined both before and during intervention to evaluate the ability of glycolipid metabolism. Exercise capacity was measured to verify the results of biochemical index. At 12 weeks and 12 + 8 weeks, infiltration was observed by H&E staining in adipose tissue, and macrophage polarization was detected by Immunofluorescence staining and ELISA.

Key finding: 1) obesity-induced IR model was established by HFD fed for 12 weeks accompanied by impaired exercise ability and increased M1 macrophage, 2) eccentric exercise accompanied by a low-fat diet markedly rescued obesity-induced IR and improved exercise capacity, 3) eccentric exercise accompanied by a low-fat diet markedly inhibited M1 macrophage polarization and activated M2 macrophage.

Significance: Eccentric exercise accompanied by a low-fat diet rescued obesity-induced IR and improved exercise capacity, which were associated with the inhibition of M1 macrophage polarization and the activation of M2 macrophage. These indicate that macrophage polarization provides the potential target of intervention for inflammation and IR in obesity.

Keywords: Diet-induced obesity; Dietary restriction; Eccentric exercise; Insulin resistance; Macrophage polarization.