نوع مقاله : مقاله پژوهشی
نویسندگان
1 دکتری فیزیولوژی ورزشی، دانشکده علوم ورزشی، دانشگاه بیرجند، بیرجند، ایران.
2 استاد گروه فیزیولوژی ورزشی، دانشکده علوم ورزشی، دانشگاه بیرجند، بیرجند، ایران.
3 دانشیار فیزیولوژِی ورزشی، گروه واحدهای عمومی، دانشکده پزشکی، دانشگاه علوم پزشکی مشهد، مشهد، ایران.
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Extended Abstract
Background and Aim: Nonalcoholic fatty liver disease (NAFLD) encompasses a spectrum of liver disorders, histologically classified into nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH). Although there is substantial evidence supporting the beneficial effects of aerobic exercise on NAFLD, the relative superiority of high-intensity interval training (HIIT) versus moderate-intensity continuous exercise remains inconclusive. Given the scarcity of comparative studies using animal models of diet-induced NAFLD, investigating the response of relevant markers to distinct training modalities may help elucidate non-pharmacological treatment pathways. The aim of this study was to compare the effects of HIIT and continuous aerobic training on serum levels of glucagon-like peptide-1 receptor (GLP-1R) and Fetuin A and insulin sensitivity in male rats with high-fat diet-induced NAFLD.
Materials and Methods: This study employed an experimental design. The statistical population of this study was male Wistar rats aged six to eight weeks with an average weight of 150 to 180 grams, which were randomly divided into four groups (each group of seven rats) including HIIT, moderate intensity continuous training (MICT), control (fatty liver disease), and healthy control (standard food). Except for the healthy control group, all rats received a high-fat diet for 12 weeks following a one-week acclimatization period. After the 12-week induction phase, seven rats were anesthetized for histopathological confirmation of hepatic steatosis; cardiac blood samples were collected for biochemical analyses and liver tissue was excised for histological assessment.
The training protocols were implemented according to Nunes et al. (2015). During the first week, rats in the training groups underwent a familiarization phase involving intermittent or continuous running for 10–30 min/day, five days/week, at 10–15 m/min. Fatigue was defined as remaining motionless on the electric grid at the end of the treadmill for 10–15 s.
Serum GLP1-R and Fetuin A concentrations were measured using a German Zelbio kit specific for rat samples (Padgin Teb). The sensitivity of the GLP1-R kit was 0.02 ng/ml, with an internal coefficient of variation of less than 10% and an external coefficient of variation of less than 12%. The sensitivity of the Fetuin A kit was 0.9 ng/ml, with an internal coefficient of variation of less than 10% and an external coefficient of variation of less than 12%. Serum insulin concentrations were measured using an Italian Mercodia kit using the ELISA method with a sensitivity of 0.15 μg/ml, and serum glucose concentrations was assessed using a Pars Azmoun Iran kit with a sensitivity of five mg/dl by calorimetry. Normality was examined using the Shapiro–Wilk test, and homogeneity of variances using Levene’s test. A one-way analysis of variance (ANOVA) was used to compare dependent variables among the four groups, followed by Tukey post hoc test when significant differences were detected. Statistical analyses were performed using SPSS version 21, with the significance level set at p≤0.05.
Findings: A descriptive summary and between-group comparison of GLP-1R, Fetuin-A, and insulin sensitivity indices in rats are presented in Table 1.
One-way ANOVA revealed significant differences in serum GLP-1R, Fetuin-A, and insulin sensitivity among the four experimental groups (Table 1). Accordingly to Tukey’s post hoc test, serum GLP-1R levels in both the HIIT and MICT groups were significantly higher than those in the NAFLD control group (p=0.008 and p=0.03, respectively): whereas no significant difference was found between the two training groups (p=0.95). Serum Fetuin-A levels were significantly lower in the HIIT and MICT groups compared to the NAFLD control group (p=0.01 and p=0.03, respectively), with no significant difference between the exercise groups (p=0.97). Similarly, insulin sensitivity was significantly higher in both HIIT and MICT groups than in the NAFLD control group (p=0.007 and p=0.01, respectively), while no significant difference was observed between these two exercise modalities (p=0.99).
Conclusion: According to the findings of the present study, fatty liver disease significantly increased serum levels of Fetuin A in rats, but both MICT and HIIT significantly decreased serum levels of Fetuin A to a level close to that of a healthy rat. Fatty liver disease significantly decreased insulin sensitivity in rats, but both trainings significantly increased insulin sensitivity to a level close to that of a healthy rat. Indeed fatty liver disease significantly decreased serum levels of GLP-1R in rats, but both trainings significantly increased this index to a level close to that of a healthy rat. No significant differences were observed between the effects of the two exercise training modalities on the investigated variables, highlighting the need for further studies in this area. Moreover, as this study was conducted on rats with diet-induced NAFLD, extrapolation of the results to humans should be performed cautiously and supported by future clinical research.
Ethical Considerations: Standard protocols and ethical principles of animal research were applied and controlled, and were reviewed and approved by the research committee of the Faculty of Sport Sciences, University of Birjand.
Funding: This article was produced without financial support.
Conflicts of interest: The authors declare that there are no conflicts of interest in this study.
کلیدواژهها [English]
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