پژوهشگاه تربیت بدنی و علوم ورزشی (وزارت علوم ، تحقیقات و فناوری) فیزیولوژی ورزشی 2322-164X 17 66 2025 06 22 Remote Ischemic Preconditioning Enhances the Effect of Aerobic Exercise on Cardiac Endoplasmic Reticulum Stress in Rats with Myocardial Infarction Model پیش‌آماده‌سازی ایسکمی دور اثر تمرین هوازی بر استرس شبکه آندوپلاسمی قلب را در موش‌های صحرایی مدل سکته قلبی تقویت می‌کند 49 34 4693 10.22089/spj.2025.18049.2373 FA عاطفه قربانی پور دانشجوی دکتری، گروه فیزیولوژی ورزشی، واحد ساری، دانشگاه آزاد اسلامی، ساری، ایران 0009-0007-4852-7070 امین فرزانه حصاری دانشیار، گروه فیزیولوژی ورزشی، واحد ساری، دانشگاه آزاد اسلامی، ساری، ایران 0000-0003-3477-8286 پروین فرزانگی استاد، گروه فیزیولوژی ورزشی، واحد ساری، دانشگاه آزاد اسلامی، ساری، ایران عبدالرضا جعفری استادیار، گروه فیزیولوژی ورزشی، واحد ساری، دانشگاه آزاد اسلامی، ساری، ایران 0000-0003-2987-8266 Journal Article 2025 05 11 <span style="mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-ascii-theme-font: major-bidi; mso-fareast-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-hansi-theme-font: major-bidi; mso-bidi-language: AR-SA;">Extended Abstract <span style="mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-ascii-theme-font: major-bidi; mso-fareast-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-hansi-theme-font: major-bidi; mso-bidi-language: AR-SA;">Background and Purpose Myocardial infarction (MI) remains a leading cause of morbidity and mortality worldwide. The endoplasmic reticulum (ER), a crucial cellular organelle, regulates calcium homeostasis, mediates protein folding, and synthesizes lipids. Disruptions caused by oxidative stress and ischemia adversely affect calcium equilibrium, resulting in accumulation of misfolded and unfolded proteins, thereby inducing ER stress. Increasing evidence implicates ER stress as a central pathogenic mechanism underlying various cardiovascular diseases. Notably, MI-induced excessive ER stress activates three primary signaling pathways leading to cardiomyocyte apoptosis. Aerobic exercise training has been demonstrated to enhance exercise capacity and cardiac function while preventing adverse remodeling of cardiac tissue, therefore serving as an effective adjunctive therapy in the prevention and treatment of cardiovascular disorders. Recent animal studies report that aerobic training mitigates oxidative stress, restores mitochondrial function, and corrects calcium handling abnormalities, positioning it as a promising modality to attenuate ER stress. Moreover, ischemic preconditioning (IPC) is an established cardioprotective strategy characterized by brief, sublethal episodes of local ischemia, which render tissues more resilient to subsequent ischemic insults. While IPC has consistently reduced infarct size in animal models, its combined effects with aerobic exercise training on ER stress regulation remain unclear. This study aimed to investigate the effects of aerobic training and IPC—applied singly or in combination—on myocardial PERK and ATF6 gene expression in a rat model of MI. <span style="mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-ascii-theme-font: major-bidi; mso-fareast-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-hansi-theme-font: major-bidi; mso-bidi-language: AR-SA;">Materials and Methods This experimental study employed a rigorous multi-group post-test design involving thirty-five male Wistar rats (8 weeks old; 225 ± 15 g). Animals were randomly allocated into seven groups: Control (C), MI, MI with one-leg ischemia (1IP), MI with two-leg ischemia (2IP), MI with aerobic training (T), MI with one-leg ischemia plus training (1IPT), and MI with two-leg ischemia plus training (2IPT).Myocardial infarction was experimentally induced by subcutaneous administration of isoproterenol (100 mg/kg) dissolved in normal saline for two consecutive days with a 24-hour interval. Confirmation of MI was obtained by measuring serum levels of cardiac troponin, creatine kinase, and lactate dehydrogenase extracted via blood samples from the medial canthus.Ischemic preconditioning was performed by applying a tourniquet to the upper hind limb(s), inducing ischemia for 5 minutes followed by 5 minutes reperfusion, repeated in 3 cycles. Complete occlusion was verified by absence of pulse, hypothermia, and cyanosis in the limb. Aerobic training commenced 20 minutes after the final IPC cycle.The aerobic exercise protocol spanned eight weeks with five sessions per week. Initial weeks involved treadmill running at 10 m/min for 15 minutes (weeks 1–2), escalating to 15 m/min for 20 minutes (weeks 3–4), 20 m/min for 25 minutes (weeks 5–6), and culminating at 25 m/min for 30 minutes (weeks 7–8), maintaining a constant 5% incline.Forty-eight hours post-training, rats were anesthetized and myocardial tissues harvested. Myocardial PERK and ATF6 mRNA expression levels were quantified using RT-PCR. Statistical analyses were performed via one-way ANOVA and Tukey post hoc tests with significance set at P < 0.05. <span style="mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-ascii-theme-font: major-bidi; mso-fareast-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-hansi-theme-font: major-bidi; mso-bidi-language: AR-SA;">Results One-way ANOVA revealed significant differences in myocardial PERK gene expression among groups (F = 59.8, P = 0.001). MI induced a marked upregulation of PERK expression compared to controls (P = 0.0001). Tukey post hoc comparisons demonstrated significant downregulation of PERK in the 1IP (P = 0.032), 2IP (P = 0.004), T (P = 0.001), 1IPT (P = 0.0001), and 2IPT (P = 0.0001) groups relative to MI alone. Moreover, combined ischemia and training groups (1IPT and 2IPT) exhibited greater PERK reduction compared to single-modality groups: 1IP (P = 0.0001; P = 0.0001), 2IP (P = 0.0001; P = 0.005), and T (P = 0.045; P = 0.031). No significant difference was observed between 1IPT and 2IPT (P = 0.935).Regarding ATF6 expression, significant group differences were observed (F = 55.1, P = 0.0001). MI significantly elevated ATF6 compared to controls (P = 0.0001). The 1IP (P = 0.0001), 2IP (P = 0.0001), T (P = 0.003), 1IPT (P = 0.0001), and 2IPT (P = 0.0001) groups demonstrated significant reductions relative to MI. Notably, 1IPT reduced ATF6 expression more than 2IP (P = 0.0001), and 2IPT presented further reduction compared to both 1IP (P = 0.048) and 2IP (P = 0.0012). No difference was found between 1IPT and 2IPT (P = 0.989). <span style="mso-bidi-font-size: 12.0pt; mso-ascii-font-family: 'Times New Roman'; mso-ascii-theme-font: major-bidi; mso-fareast-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-hansi-theme-font: major-bidi; mso-bidi-language: AR-SA;">Conclusion <span style="font-size: 11.0pt; mso-ascii-font-family: 'Times New Roman'; mso-ascii-theme-font: major-bidi; mso-fareast-font-family: Calibri; mso-hansi-font-family: 'Times New Roman'; mso-hansi-theme-font: major-bidi; mso-bidi-font-family: 'Times New Roman'; mso-bidi-theme-font: major-bidi; color: black; mso-themecolor: text1; font-weight: normal;">The induction of MI in Wistar rats is associated with elevated myocardial ER stress, as evidenced by increased expression of PERK and ATF6 genes. The present findings suggest that remote ischemic preconditioning enhances the protective effect of aerobic training in attenuating ER stress markers post-MI. This cardioprotection appears independent of the ischemic muscle mass involved (one leg vs. two legs). These data provide promising insights into combined interventions for mitigating cardiac ER stress and injury following MI. Further investigations are warranted to elucidate detailed mechanistic pathways underlying MI-induced ER stress. Article Message Ischemic preconditioning of the limb—whether unilateral or bilateral—may augment the efficacy of aerobic exercise in modulating cardiac ER stress in the context of myocardial infarction. Remote ischemic preconditioning holds potential as an adjunctive therapeutic approach to improve cardiac function and health. Nonetheless, further studies are required to validate and extend these findings. Ethical Considerations This study was approved by the Research Ethics Committee of the Medical Sciences Faculty at Sari Islamic Azad University (Ethics Code: IR.IAU.SARI.REC.1403.299). All experimental procedures complied with institutional ethical guidelines.<span style="font-size: 11.0pt; mso-ascii-font-family: 'Times New Roman'; mso-ascii-theme-font: major-bidi; mso-fareast-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; mso-hansi-theme-font: major-bidi; mso-bidi-language: AR-SA;"> Authors’ Contributions Conceptualization: Amin Farzaneh Hesari Data Collection: Atefeh Ghorbanipor Data Analysis: Parvin Farzanegi, Abdolreza Jafari Manuscript Writing: Atefeh Ghorbanipor, Parvin Farzanegi Review and Editing: Amin Farzaneh Hesari Responsible for Funding: Atefeh Ghorbanipor Literature Review: Atefeh Ghorbanipor Project Management: Amin Farzaneh Hesari Conflict of Interest The authors declare no conflict of interest. Acknowledgments AcknowledgmentsThis article is derived from the Professional Doctoral thesis in Exercise Physiology at Sari Islamic Azad University. The authors warmly thank all those who contributed to the successful completion of this research. <span lang="FA" style="font-size: 10.0pt; font-family: 'B Nazanin'; mso-ascii-font-family: 'Times New Roman'; mso-ascii-theme-font: major-bidi; mso-hansi-font-family: 'Times New Roman'; mso-hansi-theme-font: major-bidi;">هدف: استرس شبکه آندوپلاسمی قلب از طریق پروتئین‌های نادرست تاشده نقش مهمی در بیماری‌های قلبی عروقی بازی می‌کند. تمرین ورزشی ممکن است استراتژی مناسبی در تثبیت هموستاز شبکه آندوپلاسمی باشد. از طرفی، پیش‌آماده‌سازی ایسکمی اثر محافظتی در مقابل آسیب قلب دارد؛ با این حال، اثر آن به همراه تمرین مشخص نیست. هدف مطالعه‌ حاضر، بررسی اثر تمرین هوازی و پیش‌آمادهسازی ایسکمی بر بیان ژن‌های PERK و ATF6 قلب موش‌های صحرایی مدل سکته قلبی بود. <span lang="FA" style="font-size: 10.0pt; font-family: 'B Nazanin'; mso-ascii-font-family: 'Times New Roman'; mso-ascii-theme-font: major-bidi; mso-hansi-font-family: 'Times New Roman'; mso-hansi-theme-font: major-bidi;">مواد و روش ها: در این مطالعه تجربی، 35 موش صحرایی ویستار به‌صورت تصادفی به هفت گروه سالم، سکته، سکته ایسکمی یک‌ پا، سکته ایسکمی دو پا، سکته تمرین هوازی، سکته تمرین+ایسکمی یک پا، سکته تمرین+ایسکمی دو پا تقسیم شدند. سکته قلبی با تزریق ایزوپروترنول (mg/kg.day 100) در دو دوز القا شد. پیش‌آمادهسازی ایسکمی شامل سه دور پنج دقیقهای ایسکمی و پنج دقیقه جریان مجدد متعاقب بود. تمرین هوازی به مدت هشت هفته و پنج روز در هفته انجام شد که شامل دویدن روی نوار گردان با سرعت 10 متر در دقیقه و مدت 15 دقیقه در هفته‌های اول و دوم بود که در هفته‌های هفتم و هشتم به سرعت 25 متر در دقیقه و مدت 30 دقیقه رسید. بیان ژن‌های PERK و ATF6 قلب با روش real-time PCR اندازه‌گیری شد. از روش آماری واریانس یک‌طرفه و آزمون تعقیبی توکی در سطح معنا‌داری 05/0 استفاده شد. <span lang="FA" style="font-size: 10.0pt; font-family: 'B Nazanin'; mso-ascii-font-family: 'Times New Roman'; mso-ascii-theme-font: major-bidi; mso-hansi-font-family: 'Times New Roman'; mso-hansi-theme-font: major-bidi;">یافته ها: نتایج نشان داد، بیان ژن‌های PERK و ATF6 افزایش معنا‌داری در گروه سکته نسبت به گروه سالم داشت. PERK و ATF6 کاهش معنا‌داری در ایسکمی یک پا (0.0001 P=،0.032 P=)، ایسکمی دو پا (0/003P=،0.004P=)، تمرین (0.0001P=،0.0001P=)، تمرین+ایسکمی یک پا (0.0001P=،0.0001P=) و تمرین+ایسکمی دو پا (0.0001P=،0.0001P=) در مقایسه با گروه سکته داشت. <span dir="RTL" lang="FA" style="font-size: 10.0pt; line-height: 107%; font-family: 'B Nazanin'; mso-ascii-font-family: 'Times New Roman'; mso-ascii-theme-font: major-bidi; mso-fareast-font-family: Calibri; mso-hansi-font-family: 'Times New Roman'; mso-hansi-theme-font: major-bidi; mso-ansi-language: EN-US; mso-fareast-language: EN-US; mso-bidi-language: FA;">نتیجه گیری: <span dir="RTL" lang="FA" style="font-size: 10.0pt; mso-ansi-font-size: 9.0pt; line-height: 107%; font-family: 'B Nazanin'; mso-fareast-font-family: Calibri; mso-ansi-language: EN-US; mso-fareast-language: EN-US;">تمرین هوازی، پیش‌آمادهسازی ایسکمی در یک پا و دو پا منجر به بهبود استرس شبکه آندوپلاسمی قلب موش‌های صحرایی مدل سکته قلبی می‌شود؛ با این حال، تمرین هوازی به همراه پیش‌آمادهسازی ایسکمی اثر بیشتری بر بهبود استرس شبکه آندوپلاسمی بافت قلب دارد.

https://spj.ssrc.ac.ir/article_4693_1feb4cdda5aafe2a48cbe27544cd8e4b.pdf