Effects of High-Intensity Interval Training (HIIT) on miR-29c and miR-146a Expression in the Hippocampus of Streptozotocin-Induced Diabetic Male Rats

Abstract Background/objectives: MicroRNAs have recently emerged as potential biomarkers for various diseases, including diabetes, heart disease, and neurological disorders. This study aimed to investigate whether microRNA-146a, its inflammatory mediator (TNF-α), and microRNA-29c expression are altered in the hippocampus of streptozotocin-induced diabetic rats following high-intensity interval training (HIIT). Methods Twenty-four male Wistar rats (180 ± 10 g, 6–8 weeks old) were divided into four groups: control (C), diabetic (D-1w), diabetic (D-6w), and diabetic high-intensity interval training (Dia-Exe). Diabetes was induced by a single-dose intraperitoneal (i.p.) injection of streptozotocin (STZ; 55 mg/kg dissolved in 0.1 M citrate buffer, pH 4.5) in rats fasted for 12 hours with blood sugar exceeding 250. The effects of six weeks of HIIT on hippocampal microRNA-146a, microRNA-29c expression, and serum tumor necrosis factor-alpha (TNF-α) levels were evaluated using Real-Time PCR and ELISA techniques, respectively. Results Diabetic rats displayed reduced miR-146a and increased microRNA-29c expression in the hippocampus compared to controls. Additionally, TNF-α levels were elevated in the D groups compared to the C group. However, HIIT training in the Dia-Exe group significantly decreased microRNA-29c and TNF-α expression while increasing microRNA-146a expression compared to the D-6w group. Conclusion Our findings suggest that increased hyperglycemia and inflammation in diabetic rats are associated with brain impairment and negatively correlated with miR-146a and microRNA-29c expression. HIIT training appears to improve glycemic control and inflammatory conditions in diabetic rats.