en بهداشت Health تحقیقی Original article <span style="font-size:12px;"><span style="font-family:Times New Roman;"><b>Background:</b> Non-alcoholic steatohepatitis (NASH) is one of the prevalent metabolic diseases, and knowing its treatment methods is very important. This study investigates the effect of eight weeks of combined high-intensity interval training on intrahepatic FNDC5 protein and irisin in male rats with non-alcoholic steatohepatitis.<br> <b>Methods:</b> In this study, 40 rats aged 6 to 8 weeks were divided into two groups: healthy (n=20) and high-fat diet (HFD) (n=20). After eight weeks and assurance of disease induction, the HFD group was randomly divided into control-patient (n=9) and training-patient (n=9). Also, the healthy group was divided into control-healthy (n=9) and training-healthy (n=9). The training group rats performed HIIT in aquatic and land environments (Saturdays and Wednesdays in aquatic environments and Mondays on a treadmill). Western blot method was used to measure FNDC5 and irisin proteins, and the spectrophotometric method was used to measure liver enzymes (ALT and AST). One-way ANOVA and Bonferroni&#39;s post hoc test (P<0.05) were used to determine the difference between groups.<br> <b>Results:</b> After eight weeks of combined high-intensity interval training, there was no significant difference in intrahepatic FNDC5 protein levels between the groups (P=0.125). Intrahepatic irisin protein levels significantly increased in the training-healthy group compared to the control-healthy group (P=0.046). Additionally, there was a significant increase in the training-patient group compared to the control-patient group (P=0.036) and a significant increase in the training-healthy group compared to the control-patient group (P=0.011).<br> <b>Conclusion</b>: In general, combined high-intensity interval training (aquatic + land) can increase intrahepatic irisin. Thus, this type of training can be considered one of the potential non-pharmacological options for treating NAS. However, more research is needed to reach definitive results.</span></span> High-intensity interval training, Non-alcoholic steatohepatitis, High-fat diet, FNDC5 protein, rat, Lipid metabolism, FNDC5 3 7 http://goums.ac.ir/jorjanijournal/browse.php?a_code=A-10-968-1&slc_lang=en&sid=1 rahil Shahriari rahilshhryri@gmail.com 100319475328460010659 0009000607269653 No Department of Sports Sciences, Zand Institution of Higher Education, Shiraz, Iran homa sheikhani shahin hsheikhani@yahoo.com 100319475328460010660 0000000169339043 Yes Department of Sports Sciences, Zand Institution of Higher Education, Shiraz, Iran mehrzad Moghaddasi mehrzad.moghadasi@gmail.com 100319475328460010661 0000000182262570 No Department of Sports Sciences, Shiraz Branch, Islamic Azad University, Shiraz, Iran Alireza Jowhari afjf2020@gmail.com 100319475328460010662 0000000333441745 No Department of Sports Sciences, Faculty of Educational Sciences and Psychology, Shiraz University, Shiraz, Iran