| High-fat diet and inactivity are the bad even harmful habit to human health, which makes fatty acid supply in organizations continued to increase,this continuing high fat status will cause the body to be lower insulin sensitivity,even is more likely to result in insulin resistance(IR)phenomenon,induced other metabolic syndrome. The effects of long-term physical training on preventing metabolic disorders are well known.Fat is the major energe material during endurance exercise training,which can effectively alleviate the negative effects that high-fat diet induced;on the other hand,endurance training have an significant effect in improving mitochondrial function,enhancing the activity of mitochondrial lipid oxidation and related gene expression.In human body,stored fat is richer than carbohydrate,but the capacity of fatty acid oxidation is limited,the reasons for this restriction on the use of stored fat have not yet been fully explained.Mitochondrial lipid oxidation as the rate-limiting step in fat metabolism,which affect fatty acid oxidation from many aspects,such as the existence of mitochondrial membrane carnitine acyltransferase(CPT)system,various of mitochondrial membrane-binding proteins,phosphoric acid AMP-activated protein kinase(AMPK),and so on.In addition,peroxisome proliferator-activated receptory coactivator 1(PGC-1)has drawn greater attention in recent years,PGC-lαhas a variety of physiological functions and plays an important role in mitochondrial biosynthesis,transformation of muscle fiber types,glucose metabolism,fatty acid oxidation,etc.Thus,the aim of this study was to investigate the effects of 8-week endurance training on mitochondrial lipid oxidation-related enzymes and genes expression in high-fat diet Sprague-Dawley rats,discuss the mechanism of endurance training role on improving the lipid oxidation level and reducing the IRI in high-fat diet rats. Methods:24 four-week-old male Sprague-Dawley rats,with a body weight of 100±5g were randomly assigned to standard diet control group(C,n=6),standard diet endurance training group(E,n=6),high-fat diet control group(H,n=6),high-fat diet endurance training group(R,n=6).Endurance training group rats were accustomed to 8-week treadmill training with a speed of 0.8km/h-1.2km/h at an 0%incline,for 40min/d during the first 4-week time,then maintained for 60min/d for the following four weeks.After all Rats were sacrificed,plasma insulin concentration was measured using Enzyme-Linked ImmunoSorbant Assay(ELISA)method;blood glucose concentration and mitochondrial acyl-coenzyme A hydroxybutyrate dehydro-genase (β-HAD)activity,citrate synthase(CS)activity were measured using Colori-metry method.Detected CPT-1β,PGC-lαgene transcription and protein expression level with real-time quantitative PCR(RT-Q-PCR)and Western Blotting respectively. Results:1)Endurance training reduced high IR index in the high-fat diet rats.(IR index=Fasting blood glucose concentrations×fasting insulin concentration)/22.5); 2)Endurance training significantly increased the activity ofβ-HAD,CS in skeletal muscle mitochondrial of high-fat diet rats;3)Endurance training increased CPT-1βgene transcription level in high-fat diet rats,but had no apparent effect on CPT-1βprotein expression;4)Endurance training decreased PGC-lαgene transcription level in high-fat diet rats,but up-regulated PGC-lαprotein expression.Conclusion:1)Endurance training can significantly control the gain in weight in high-fat diet rats;2)Endurance training would help the high-fat diet rats maintain a normal level in insulin resistance index;3)Endurance training upregulated CPT-1βgene transcription,Enhance the activity of mitochondrial fat oxidation,alleviate the negative effects of high-fat diet rats;4)Endurance training significantly increased mitochondrial fat oxidation level in high-fat diet rats by regulating PGC-lαprotein expression,which may be played a key role in the coordination between mitochondrialβ-oxidation and TCA.
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