Tehran University Medical Journal (Mar 2020)
Effect of interval and continuous training exercises after high-fat diet on liver X receptor alpha gene expression
Abstract
Background: A group of adenosine triphosphate binding cassette transporter (ABCs) including ABCA1, ABCG1, ABCG4, ABCG5 and, ABCG8 induce cholesterol efflux from the cell and thereby are target genes in prevention and treatment of atherosclerosis. ABCA1, ABCG5 and, ABCG8 genes are activated by liver X receptor (LXR) and liver receptor homolog-1 (LRH-1) that play essential roles in metabolic processes related to cholesterol metabolism. Oxysterols that are derivatives of cholesterol, or by-products of cholesterol biosynthesis that contain additional oxygen functions as hydroxyl, carbonyl, or epoxide groups, are LXR ligands; thus, LXR and LRH-1 are cell cholesterol sensors. LXRs are ligand-activated transcription factors that regulate the metabolism of several genes related to lipids, cholesterol, and bile acids and their activity is effective in the prevention of atherosclerosis. The aim of this study was to investigate the effects of 12 weeks high-intensity interval training (HIT) and low-intensity continuous training (LIT) after high-fat diet on LXRα gene expression in male Wistar rats. Methods: This experimental study was done in two phases of obesity induction and training exercises. The rats after 13 weeks of high-fat diet (40% lipid) assigned in 3 groups of control (with high-fat diet) (N=5), HIT training (with high-fat diet) (N=5) and LIT training (with high fat diet) (N=5). For statistical analysis, the one-way ANOVA and the least significant difference (LSD) post-hoc tests were used for comparison of groups. The duration of exercises was 12 weeks (5 sessions per week). The research was done in the Sport Sciences Research Institute of Shahid Mirghani, Gorgan City, Iran, from December 2018 to July 2019. Results: Results showed significant differences of LXRα gene expression between groups (P≤0.05), as highest levels of LXRα gene expression were in HIT group and its lowest levels were in control group. Conclusion: In summary, results showed that 12 weeks high-intensity interval training (HIT) and low-intensity continuous training after 13 weeks high-fat diet increased LXRα gene expression that may be a predictive mechanism for atherosclerosis especially in obese persons. Also, HIT training was more effective in elevation of LXRα gene expression.
