Tehran University of Medical Sciences Acta Medica Iranica 0044-6025 64 9 2026 08 19 550 556 Tannaz Parsazadegan Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. AND Anesthesiology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran. Kamran Rakhshan Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Mahdieh Faghihi Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Fataneh Esmaeili Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. Shadi Seyyed Ebrahimi Department of Clinical Biochemistry, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran Alireza Imani 1 Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. AND Sleep Breathing Disorders Research Center (SBDRC), Tehran University of Medical Sciences, Tehran, Iran. AND Occupational Sleep Research Center, Tehran University of Medical Sciences, Tehran, Iran 2025 08 03 2025 11 05 Epidemiological studies have demonstrated an association between sleep duration and various health risk factors, including obesity and cardiovascular diseases, particularly coronary artery disease (CAD). The present study aimed to examine the impact of sleep disruption (SD) prior to myocardial infarction (MI) on cardiac injury, with a specific focus on matrix metalloproteinases (MMPs) as potential mediators of this relationship. Using a controlled animal model, adult male Wistar rats were subjected to chronic SD for 14 days, followed by induction of MI via isoproterenol administration. The activities of MMP-2 and the level of tissue inhibitor of metalloproteinase-1 (TIMP-1) were assessed, alongside histological evaluations of cardiac tissue and oxidative stress markers. Results indicated a significant reduction in the TIMP-1/β-actin ratio in the MI and SD+MI groups, with a more pronounced decrease in the SD+MI group, and an increase in MMP-2 activity in the MI group compared to the control group, suggesting an imbalance between MMPs and TIMPs that may contribute to myocardial damage. Histological analysis revealed notable disorganization of myocardial fibers, which appeared more severe in the SD+MI group, highlighting the detrimental impact of SD on cardiac tissue integrity. Although no significant alterations in oxidative stress markers were detected, the findings underscore the detrimental role of SD in cardiovascular health and suggest that this imbalance between MMPs and TIMPs could serve as a potential mechanism involved in cardiovascular diseases associated with SD. https://acta.tums.ac.ir/index.php/acta/article/view/11753 https://acta.tums.ac.ir/index.php/acta/article/download/11753/6096