Journal of Exercise & Organ Cross Talk
Journal of Eexercise & Organ Cross Talk

The effect of aerobic exercise and ethanolic extract of bitter orange peel on cardioprotective genes expression in female rats fed a high-fat diet

Document Type : Original Article

Authors

Shahrzad Haji Ali Akbar 1
Mohammad Ali Azarbayjani 1
Shahin Riyahi Malayeri 2
Hoseyn Fatolahi 3

1 Department of Physical Education and Sport Sciences, CT.C., Islamic Azad University, Tehran, Iran.

2 Department of Physical Education and Sport Sciences, ET.C., Islamic Azad University, Tehran, Iran.

3 Department of Physical Education and Sport Sciences, P.C., Islamic Azad University, Pardis Iran.

https://doi.org/10.22122/jeoct.2025.531768.1160
Abstract
The present study evaluates the effects of aerobic exercise and ethanolic bitter orange peel extract on the expression of cardioprotective genes in female rats fed a high-fat diet (HFD). From the Islamic Azad University's Central Tehran Branch animal facility, 30 adult female rats of the Wistar strain were randomly assigned to five groups (six rats per group): 1) normal diet control (ND-C), 2) HFD control (HFD-C), 3) HFD aerobic exercise (HFD-AE), 4) HFD ethanolic bitter orange peel extract (HFD-BP), and 5) HFD aerobic exercise and ethanolic bitter orange peel extract (HFD-AE-BP). A normal diet was supplemented with 20% palm oil, 1.5% cholesterol, and 0.25 cholic acid to induce obesity. Before the intervention, the subjects received a HFD for four weeks, then continued it for another four weeks during the intervention. During the four-week aerobic exercise protocol, treadmill running was performed at a moderate intensity. An ethanol extract of bitter orange peel was administered orally to rats at a dose of 100 milligrams per kilogram of body weight for four weeks. After euthanasia, left ventricle myocardium was collected for real-time PCR analysis of CTRP9, LKB1, and AMPK gene expression. In the HFD-C, CTRP9 (P=0.001), LKB1 (P=0.001), and AMPK (P=0.001) genes were significantly lower than in the ND-C. Aerobic exercise significantly increased their expression compared with the HFD-C (P=0.001). Comparing HFD-C with ethanolic bitter orange peel extract, ethanolic bitter orange peel extract increased gene expression significantly (P=0.001). This indicates that the simultaneous use of these two interventions was able to add up the effects of each and did not have a synergistic effect. However, since the magnitude of change when these two interventions were combined was greater than the effect of each alone, the combination of AE and BP was greater than the effect of each alone, suggesting that these two interventions may be used to mitigate cardiac complications under HFD conditions.

What is already known on this subject?

The presence of obesity is a major risk factor for structural and functional changes in the myocardium, which may lead to cardiovascular complications and increased mortality.

 

What this study adds?

The present study shows that HFD negatively affects myocardial tissue by suppressing the CTRP9, LKB1, and AMPK genes. They play a critical role in energy metabolism, fat accumulation, apoptosis, and myocardial function. Both aerobic exercise and ethanolic bitter orange peel extract significantly reduced the adverse effects of HFD on the expression of these genes. In spite of the fact that these two interventions did not synergistically enhance gene expression, the highest gene expression was observed when they were combined. This indicates the additive effect of these two interventions on gene expression. As a result of reducing inflammation, oxidative stress, and improving metabolic status, aerobic exercise and bitter orange peel extract appear to increase expression of the studied genes. In obese subjects induced by HFD, aerobic exercise and ethanolic bitter orange peel extract exhibit cardioprotective effects and protect myocardial tissue. CTRP9, LKB1, and AMPK genes are upregulated in order to accomplish this. In order to reduce cardiac complications under HFD conditions, these two interventions should be used.

 

Keywords

CTRP9
LKB1
AMPK
Aerobic exercise
Bitter orange peel

Subjects

Acknowledgements

This study is derived from a doctoral thesis in Exercise Physiology. It was approved by the Department of Physical Education and Sport Sciences at the Islamic Azad University, Central Tehran Branch. The authors would like to express their sincere gratitude to the staff of the exercise physiology departments.

Funding

No sources of funding were sought or awarded for this study.

Data availability

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Compliance with ethical standards

Conflict of interest The authors declare that they have no conflict of interest.

Ethical approval the study protocol conformed to the Declaration of Helsinki and was approved by the animal care and use committee of Islamic Azad University Central Tehran branch.

Informed consent Animal study.

Author contributions

Conceptualization: SH.H.A.A, M.A.A, SH.R.M, H.F,; Methodology: SH.H.A.A, M.A.A, SH.R.M, H.F,;  Software: SH.H.A.A, M.A.A, SH.R.M, H.F,; Validation: SH.H.A.A, M.A.A, SH.R.M, H.F,; Formal analysis: SH.H.A.A, M.A.A, SH.R.M, H.F,; Investigation: SH.H.A.A, M.A.A, SH.R.M, H.F,;   Resources: SH.H.A.A, M.A.A, SH.R.M, H.F,; Data curation: SH.H.A.A, M.A.A, SH.R.M, H.F,; Writing - original draft: SH.H.A.A, M.A.A, SH.R.M, H.F,; Writing - review & editing SH.H.A.A, M.A.A, SH.R.M, H.F,; Visualization: SH.H.A.A, M.A.A, SH.R.M, H.F,;  Supervision: SH.H.A.A, M.A.A, SH.R.M, H.F,; Project administration: SH.H.A.A, M.A.A, SH.R.M, H.F,; Funding acquisition: SH.H.A.A, M.A.A, SH.R.M, H.F.

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Journal of Exercise & Organ Cross Talk
Volume 5, Issue 2
Spring 2025
Pages 59-66

  • Receive Date 30 April 2025
  • Revise Date 04 June 2025
  • Accept Date 05 June 2025

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