نوع مقاله : مقاله پژوهشی
نویسندگان
1 کارشناس ارشد فیزیولوژی ورزشی، گروه تربیت بدنی و علوم ورزشی، واحد بجنورد، دانشگاه آزاد اسلامی، بجنورد، ایران.
2 استادیار گروه تربیت بدنی و علوم ورزشی، واحد بجنورد، دانشگاه آزاد اسلامی، بجنورد، ایران.
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Extended Abstract
Background and Aim: Aging is a complex and gradual process that leads to a decline in physiological function and an increased the chronic diseases. Obesity, as a chronic inflammatory condition, is an accelerator of aging and could affects metabolism, appetite, insulin sensitivity, and fat distribution through the secretion of adipokines. Among adipokines, Semaphorin C3 (Sema3C) and Lipocalin 2 (LCN2) play an important roles in the pathophysiology of obesity and metabolic disorders. Studies have reported increased expression of these two proteins in conditions of obesity and aging. Despite nutritional and pharmacological treatments, exercise—particularly resistance training (RT), endurance training, and high-intensity interval training (HIIT)—has been identified as the most effective strategy for reducing the negative effects of obesity in old age. These exercises play a key role in improving metabolism and preventing premature aging by enhancing body composition, reducing inflammation, and regulating adipokines, including Sema3C and LCN2. The present study aims to to investigate the effects of RT and HIIT on the expression of these adipokines in the adipose tissue of obese aged mice.
Materials and Methods: This experimental study was conducted on 30 elderly male Wistar rats (aged 20–22 months) at the Islamic Azad University, Bojnourd branch. The animals were maintained under controlled conditions: temperature of 25±3 C, humidity of 55–60%, and a 12:12 hour light-dark cycle for one week of acclimation. Following acclimation, to induce obesity, the rats were fed a high-fat diet (HFD) consisting of 40% fat, 13% protein, and 47% carbohydrate for eight weeks. Rats with a Lee index greater than 310 were designated as obese and randomly divided into three groups of 10: obese control (OC), RT, and HIIT. The RT protocol involved ladder climbing with a tail attachment, starting at 30% of body weight and progressively increasing up to 200% of body weight. The HIIT protocol consisted of short-duration sprints at 85–90% of maximal velocity interspersed with active recovery periods. Moreover, the control group underwent no exercise but was exposed to the sound of the treadmill motor only. Forty-eight hours after the final training session, and after an eight-hour of fasting, the rats were anesthetized, and subcutaneous fat samples were collected for RNA extraction and cDNA synthesis. The gene expression of Sema3C and LCN2 was quantified using Real-time-PCR, with β-Actin serving as the reference gene for normalization. The data were entered into SPSS version 25 and analyzed using descriptive statistics, Shapiro‑Wilk test (for normality), Levene’s test (for homogeneity of variances), one‑way analysis of variance (ANOVA), and Tukey’s post‑hoc test, with the significance level set at p≤0.05.
Findings: The ANOVA test showed the expression of Sema3C (p=0.001), LCN2 (p=0.01), and the Lee index (p=0.001) were significant differences between the RT, HIIT, and OC groups. Moreover, the results of Tukey’s post hoc test indicated a significant difference between the RT and HIIT groups compared to the OC group in the dependent variables. Specifically, the expression of Sema3C (p=0.001), LCN2 (p=0.003), and the Lee index (p=0.001) were significantly decreased in the training groups compared to the OC group. However, no significant differences were observed between the RT and HIIT groups in the expression of Sema3C (p=0.12), LCN2 (p=0.08), and the Lee index (p=0.10).
Conclusion: The results of this study demonstrated that eight weeks of both RT and HIIT led to a significant down regulation in the gene expression of Sema3C and LCN2, alongside a meaningful reduction in the Lee index in obese aged male rats. The Sema3C gene, a member of the Class 3 semaphorin family, is recognized as a novel adipokine that is implicated in body weight alterations, insulin resistance, and adipose tissue structure. Limited research has previously explored the direct effect of exercise on Sema3C. The current findings align with reports from Supriya et al. (2023) and Saeedi et al. (2023), who documented a significant decrease in Sema3C expression following twelve weeks of CrossFit or high-intensity functional training in obese human subjects. Furthermore, other existing literature indicates that endurance and HIIT exercise protocols are associated with reduced levels of related Semaphorins, such as Sema3A, Sema3B, and Sema3G, in laboratory animals, contributing to improved metabolic parameters (Liu et al., 2020; Ghadiri Haramati et al., 2017). Therefore, it is hypothesized that the reduction observed in Sema3C and other semaphorins primarily results from the decrease in overall fat mass, given that adipose tissue serves as the main secretory source for these adipokines. Conversely, the LCN2 gene is recognized as a key inflammatory marker and an oxidative stress response factor whose levels typically escalate in conditions of obesity, aging, and metabolic diseases. The observation in this research of a decrease in LCN2 expression is consistent with reports by Esmaeili et al. (2018) and Fattahpour Marandi et al. (2023), also noted a significant reduction following aerobic and RT protocols. A potential mechanism for this downregulation involves the suppression of the inflammatory nuclear factor-kappa B (NF-kB ) pathway, which is activated under oxidative conditions and drives LCN2 expression; conversely, physical activity suppresses this pathway, consequently reducing inflammation and enhancing insulin sensitivity. In line with these molecular changes, the significant decrease in the Lee index observed in this study indicates reduced body fat mass and improved metabolic status in elderly obese rats. In conclusion, consistent, structured regular exercise, whether RT or HIIT, can substantially improve the metabolic function of adipose tissue during senescence by downregulating genes associated with inflammation and insulin resistance, thereby potentially preventing the onset of obesity-related metabolic disorders.
Compliance with Ethical Guidelines: All experimental procedures were conducted in accordance with ethical guidelines for animal research and were approved by the Ethics Committee of Bojnourd Azad University (Approval Code: IR.IAU.BOJNOURD.REC.1402.004). All procedures were performed minimizing pain and distress to the animals.
Funding: This research is based on a master’s thesis from a student at the Islamic Azad University, Bojnourd Branch, and was conducted without any financial support.
Conflicts of interest: There are no conflicts of interest regarding this article.
کلیدواژهها [English]
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