Anti-Inflammatory Potential of Continuous and High-Intensity Interval Training in Cardiac Injury: Gene Expression Changes of TNF-α and IL-6 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-6 gene expression in MI-induced rats. Methods: Forty male Wistar rats were randomized into control, MI, MI+MICT, and MI+HIIT groups (10 animals per group). MI was induced by left anterior descending artery occlusion and confirmed by echocardiography. Following recovery, rats completed 8 weeks of treadmill training (MICT: 50–60% VO₂max; HIIT: 85–90% VO₂max). Finally, cardiac TNF-α and IL-6 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 (38±5% vs. 68±4%, P<0.001). TNF-α increased in MI (2.6±0.4 vs. 1.0±0.2, P<0.001) but decreased after MICT (1.7±0.3; P=0.001) and HIIT (1.3±0.2, P<0.001). Moreover, IL-6 rose in MI (2.9±0.5 vs. 1.0±0.2, P<0.001) but declined after MICT (2.0±0.4, P=0.002) and HIIT (1.8±0.3, P<0.001). Additionally, TNF-α reduction was greater with HIIT than MICT (Δ=0.4, P=0.010), while IL-6 changes were not significant (P=0.180). Conclusion: Overall, both MICT and HIIT mitigated cardiac inflammation after MI by reducing TNF-α and IL-6 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.