Sajjad Hejazi; Yousef Doustar; Koroush Malek-Mohammadi; Murat Boydak; Shadi Asadabadi; Mohammad-Ali Rezvandoust & Shaghayegh Mohajeri

Restoring blood flow to ischemic heart muscle can induce more damage to myocardium. The purpose of this study was to evaluate effects of regular increasing long-term aerobic exercise on cardiac Ischemia/Reperfusion (I/R) injury in rats. For this purpose, 40 male Wistar rats were randomly allocated in 4 equal groups including: control, I/R, I/R with two weeks of aerobic exercise, and I/R with eight weeks of regular increasing aerobic exercise groups. Aerobic exercise was performed 5 times per week on treadmill at speed of 10-25 m/min for 10-30 min with the slope of 5 degrees. For induction of I/R injury, left descending coronary artery was clamped for 30 min, thereafter blood flow was restored for 2 h. Blood samples were collected for measurement of serum cardiac biomarkers including: creatine kinase-MB (CK-MB), lactate dehydrogenase (LDH), cardiac troponin I (cTnI) and tumor necrosis factor alpha (TNF-α). Finally, all animals were euthanized for histopathological examination and assessment of myocardial antioxidant status. Aerobic exercise significantly decreased the CK-MB, LDH, cTnI and TNF-α serum levels, which were increased following I/R injury and significantly increased the cardiac levels of SOD, CAT and GPx, which were reduced in these animals, as well as significantly decreased MDA level (P<0.05). Microscopically, aerobic exercise significantly alleviated myocardial degenerative and necrotic changes and significantly decreased the number of apoptotic cells (P<0.05), which were increased due to I/R injury. The results showed regular increasing long term aerobic exercise protects the cardiac muscle of rats following I/R injury.

KEY WORDS: Apoptosis; Exercise; Heart; Ischemia-reperfusion; Rat; Serum biomarkers.

HEJAZI, S.; DOUSTAR, Y.; MALEK-MOHAMMADI, K.; BOYDAK, M.; ASADABADI, S.; REZVANDOUST, M-A. & MOHAJERI, S. The effect of regular treadmill exercise on heart histopathological changes and biochemical alterations in cardiac ischemia-reperfusion injury in rat. Int. J. Morphol., 4(3):903-912, 2026.