نوع مقاله : مقاله پژوهشی
نویسندگان
1 دانشیار گروه علوم ورزشی، دانشکده ادبیات و علوم انسانی، دانشگاه قم، قم، ایران.
2 کارشناسی ارشد فیزیولوژی ورزشی، گروه علوم ورزشی، دانشکده ادبیات و علوم انسانی، دانشگاه قم، قم، ایران.
3 دانشجوی دکتری فیزیولوژی ورزشی، گروه علوم ورزشی دانشکده علوم اجتماعی، دانشگاه بین المللی امام خمینی (ره)، قزوین، ایران.
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Extended Abstract
Background and Aim: The global population is rapidly aging, a major health challenge projected to affect 1.5 billion people by 2050, intensifying healthcare demands for age-related conditions like falls. A key consequence of aging is the decline in bone density and the rise of skeletal issues like osteoporosis. This is especially prevalent in elderly postmenopausal women, who face accelerated bone mass loss from hormonal changes. The underlying mechanism involves a disrupted bone-remodeling process, in which osteoblast activity declines while osteoclast activity remains unchanged, leading to a net reduction in bone density. Recent studies have highlight the role of micro ribonucleic acids (microRNAs), such as miR-223 and miR-92, in regulating bone metabolism, and show that their expression is altered with age. Recognizing that physical activity, especially aerobic exercise, is a known countermeasure against bone loss, our study investigated how 12 weeks of aerobic exercise impacts the expression of these specific microRNAs in elderly women.
Materials and Methods: This semi-experimental study, with a control group, involved 30 elderly women (ages 65-70 y) selected from retired education personnel in Qom’s first district. From an initial pool of 60 volunteers, 30 were selected based on inclusion criteria: physical and mental health, at least five years post-menopause, and no history of specific diseases (cardiovascular-respiratory), regular physical activity, smoking, or special diets/therapeutic interventions within the previous six months. Exclusion criteria were irregular attendance, injury, the development of illness during the study. Before beginning, participants completed medical history, 24-hour dietary recall, PAR-Q (questionaire), and personal information forms, and then signed informed consent. They were then randomly assigned to either an experimental or control group (n=15 each). The study was ethically approved by Qom University (ID: IR.QOMREC.1399.018). The experimental group participated in a 12-week aerobic exercise program, three sessions per week. Each session, lasted 25-45 minutes, consisted of running at 50-75% maximum heart rate, a 10-minute warm-up, and a 5-minute cool-down. Intensity increased by 5% every two weeks and duration by 2 minutes weekly. Heart rate was monitored with polar series toolkit monitors. All sessions were held from 9-11 AM in the university’s indoor sports hall. The control group maintained their normal routines, avoiding intense activity. Blood samples (5 cc) were collected from the antecubital vein after a 12-hour fast, 48 hours before the first session and 48 hours after the last. Samples were centrifuged at 3000 RPM for 10 minutes and stored at −80 ∘C. MicroRNA was extracted using an Irizol RNA extraction kit (Zist Fanavarane RNA, code RB1001). Real-Time PCR, using SYBR Green Master Mix on a Rotor-Gene Q (Qiagen) system, was performed. Data were analyzed with the Livak (2−ΔΔCT) method. Statistical analysis included the Shapiro–Wilk test to verify normality and ANCOVA for between-group comparisons, using SPSS version 26. The significance level was set at p<0.05.
Findings: Table 1 presents the results of descriptive and inferential statistical analyses. Pre-test measurements of microRNA expression revealed comparable levels of miR-223 between groups. Indeed, post-test analysis demonstrated highly significant and distinct changes in the exercise group. Covariance analysis (ANCOVA) indicated that the 12-week aerobic exercise program exerted a highly significant effect on the expression of both microRNAs compared to the control group. Specifically, a highly significant difference was observed for miR-223 expression (F(1,27)=21.64, p<0.0001), with the exercise intervention resulting in a 29.6% reduction. Similarly, miR-92 expression showed a significant difference (F(1,27)=13.14, p<0.0001), with aerobic exercise leading to a 71.2% increase. miR-223 expression in the exercise group decreased significantly to 3.52±0.60, whereas the control group showed minimal changes. This substantial reduction highlights a profound molecular response to the exercise intervention. Regarding miR-92, the exercise group demonstrated a significant increase to 3.97±0.98, while the control group remained relatively stable at 2.23±0.51. This upregulation of miR-92 further underscores the molecular impact of the exercise program.
Conclusion: The results demonstrate that 12 weeks of aerobic exercise performed at 50-75% maximum heart rate intensity significantly modulates bone-related microRNA expression in elderly women. The observed 29.6% decrease in miR-223 expression may contribute to reduced inflammatory processes, decreased osteoclast activity, and enhanced osteoblast differentiation, while the 71.2% increase in miR-92 expression may support cartilage formation and bone morphogenetic protein signaling pathways. These molecular changes along with previous research showing that aerobic exercise influences bone metabolism through increased bone blood flow, improved nutrient delivery, and reduced inflammatory markers. The modulation of miR-223 may involve interactions with FOXO3, potentially enhancing bone formation, while increased miR-92 expression may promote osteogenesis through related signaling pathways. Based on the results, it appears that 12 weeks of aerobic exercise at an intensity of 50-75% improves miR-223 and miR-92, ultimately helping to prevent bone density loss in elderly women. These novel findings provide compelling molecular evidence for exercise-induced improvements in bone metabolism, however, further research is required to fully elucidate the underlying mechanisms and to optimize exercise prescriptions for preventing age-related bone loss.
Ethical Considerations: This study was approved by the Ethics Committee of Qom University (ID: IR.QOMREC.1399.018).
Compliance with Ethical Guidelines: All participants provided informed consent after receiving complete information about the study procedures.
Funding: This research was extracted from a master’s thesis in exercise physiology in university of Qom.
کلیدواژهها [English]
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