Anti-Inflammatory Potential of Continuous and High-Intensity Interval Training in Cardiac Injury: Gene Expression Changes of TNF-α and IL-۶ Following Myocardial Infarction

Background and aims: Myocardial infarction (MI) induces chronic inflammation and cytokine overexpression. This randomized controlled experiment investigated the effects of moderate-intensity continuous training (MICT) and high-intensity interval training (HIIT) on cardiac tumor necrosis factor-alpha (TNF-α) and IL-۶ gene expression in MI-induced rats. Methods: Forty male Wistar rats were randomized into control, MI, MI+MICT, and MI+HIIT groups (۱۰ animals per group). MI was induced by left anterior descending artery occlusion and confirmed by echocardiography. Following recovery, rats completed ۸ weeks of treadmill training (MICT: ۵۰–۶۰% VO₂max; HIIT: ۸۵–۹۰% VO₂max). Finally, cardiac TNF-α and IL-۶ messenger RNA levels were measured by quantitative polymerase chain reaction and analyzed using one-way ANOVA. Results: Ejection fraction was lower in MI rats than in controls (۳۸±۵% vs. ۶۸±۴%, P<۰.۰۰۱). TNF-α increased in MI (۲.۶±۰.۴ vs. ۱.۰±۰.۲, P<۰.۰۰۱) but decreased after MICT (۱.۷±۰.۳; P=۰.۰۰۱) and HIIT (۱.۳±۰.۲, P<۰.۰۰۱). Moreover, IL-۶ rose in MI (۲.۹±۰.۵ vs. ۱.۰±۰.۲, P<۰.۰۰۱) but declined after MICT (۲.۰±۰.۴, P=۰.۰۰۲) and HIIT (۱.۸±۰.۳, P<۰.۰۰۱). Additionally, TNF-α reduction was greater with HIIT than MICT (Δ=۰.۴, P=۰.۰۱۰), while IL-۶ changes were not significant (P=۰.۱۸۰). Conclusion: Overall, both MICT and HIIT mitigated cardiac inflammation after MI by reducing TNF-α and IL-۶ gene expression, with HIIT producing a more potent anti-inflammatory effect on TNF-α. These molecular findings suggest that HIIT may offer enhanced anti-inflammatory benefits in post-MI rehabilitation strategies.