Extended Abstract

1.   Introduction and Objective

Type 2 diabetes mellitus (T2DM) is one of the most prevalent metabolic disorders worldwide. Its incidence has increased dramatically in recent decades, positioning it as a major risk factor for cardiovascular disease. T2DM is characterized by chronic hyperglycemia which, through mechanisms such as exacerbated oxidative stress, chronic inflammation, and mitochondrial dysfunction, can lead to structural and functional damage in vital organs, particularly the heart. Indeed, many diabetes-related cardiovascular complications result from an imbalance between the production of reactive oxygen species (ROS) and the capacity of antioxidant defense systems—a state defined as oxidative stress. Oxidative stress is a primary driver of diabetic cardiomyopathy, especially in the aging population. Regular physical activity is recognized as a non-pharmacological strategy to bolster antioxidant defenses and mitigate oxidative damage. This study aimed to compare the effects of eight weeks of aerobic and concurrent training on the activity of antioxidant enzymes and lipid peroxidation in the cardiac tissue of elderly, overweight, diabetic male rats.

2.   Materials and Methods

This experimental study was conducted on 30 elderly male Wistar rats (aged 24–28 months; mean weight approximately 320 g). Animals were housed under standardized laboratory conditions: temperature 20–22°C, humidity 55–65%, and a 12:12-hour light-dark cycle. They had ad libitum access to water and standard pellet feed, sourced from Khallaghan-e Teb Pouya (Tehran, Iran). The feed was verified for chemical and microbial quality and formulated with high-quality proteins, essential fatty acids, vitamins, and minerals, without synthetic preservatives. After diabetes induction, the rats were randomly assigned to three groups: Control, Aerobic Training (AT), and Concurrent Training (CT). The AT protocol consisted of running at an intensity of 60–75% of Vmax, five sessions per week for eight weeks. The CT protocol combined aerobic running with resistance training (ladder climbing at 60–80% of one-repetition maximum). Forty-eight hours after the final training session, cardiac tissue samples were collected. The levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX), and malondialdehyde (MDA) were measured using ELISA kits. Data were analyzed using one-way ANOVA followed by Tukey's post hoc test (P ≤ 0.05).

3.   Findings

Significant differences in SOD, CAT, GPX, and MDA levels were observed among the groups (P<0.001). Both training modalities increased antioxidant enzyme activity and decreased MDA levels compared to the control group (P<0.001). Furthermore, concurrent training induced greater improvements than aerobic training alone (P < 0.001).

4.   Conclusions

Comparing the two training modalities, improvements in all measured indices were significantly more pronounced in the concurrent training group than in the aerobic training group. This finding suggests that integrating resistance training into an aerobic exercise program provides significant added value in promoting anti-inflammatory and antioxidant adaptations in cardiac tissue. The observed changes, supported by physiological principles, may be attributed to several cellular and molecular mechanisms: Activation of the Nrf2/ARE pathway: Exercise enhances the phosphorylation and nuclear translocation of the Nrf2 transcription factor, upregulating antioxidant genes such as SOD2, CAT, and GPX in cardiomyocytes. Enhanced mitochondrial biogenesis: Activation of the AMPK/PGC-1α signaling pathway promotes mitochondrial biogenesis in cardiomyocytes, thereby reducing electron leakage from the respiratory chain and subsequent reactive oxygen species (ROS) production. Reduction of oxidative stress and lipid peroxidation: The coordinated upregulation of SOD, CAT, and GPX leads to more effective neutralization of ROS, preventing lipid peroxidation of cell membranes, as evidenced by reduced MDA levels. In conclusion, eight weeks of exercise training, particularly concurrent training, enhances the antioxidant capacity and attenuates oxidative stress in the cardiac tissue of elderly diabetic rats. Concurrent training appears to be an effective strategy for mitigating oxidative damage and improving cardiac health in the context of diabetes and aging.

5.      Acknowledgment & Funding

This article is not sponsored

6.   Ethical Considerations

This research was approved by the ethics committee

with the ethical code of IR.IA.AEC.1404.087.

7.   Authors' Contributions

All authors have actively participated in the process of the study and writing the article.

8.   Conflict of Interest

The authors declare no conflict of interest.