Combined crocin and treadmill exercise regulate cardiac MicroRNA-23b, nuclear factor Erythroid 2-related factor 2, and tumor necrosis factor-alpha in experimental type 2 diabetes mellitus

Diabetic cardiomyopathy is a major complication of type 2 diabetes mellitus and is strongly associated with chronic inflammation, oxidative imbalance, and cardiomyocyte apoptosis. MicroRNAs, particularly miR-23b, have emerged as important regulators of inflammatory and metabolic responses; however, its modulation by combined nutritional and exercise interventions in diabetic cardiac tissue remains unclear. The present study evaluated the effects of combined crocin supplementation and treadmill exercise on miR-23b expression and levels of TNF-α, and NRF2 in the heart tissue of rat model of type 2 diabetes mellitus (T2DM).

Thirty-five male Wistar rats were randomly allocated into healthy control and diabetic groups. Type 2 diabetes mellitus was induced in 28 rats using a high-fat diet for four weeks followed by a single intraperitoneal injection of streptozotocin (35 mg/kg). Diabetic rats were divided into four groups (n = 7/group), including diabetic control, crocin-treated (50 mg/kg/day), treadmill exercise, and combined crocin plus exercise groups and treated for eight weeks using combined crocin (50 mg/kg/day) and treadmill exercise. Next, heart tissues were isolated and the gene expression of miR-23b was assessed via SYBR-Green real-time RT-PCR, and the protein levels of TNF-α and NRF2 were measured by ELISA. In addition, apoptosis rate was evaluated by TUNEL method.

Combined crocin and treadmill exercise significantly reduced cardiac TNF-α levels from 8.50 pg/mL in diabetic control rats to 3.78 pg/mL, corresponding to a 55.5% reduction (p < 0.001). In contrast, NRF2 levels increased from 0.2 to 0.82 ng/mg protein, representing a 310% increase following the combined treatment (p = 0.0002). Furthermore, miR-23b expression increased from 0.72-fold in diabetic control rats to 1.82-fold following combined treatment, corresponding to a 151.8% increase (p < 0.001). Combined treatment also significantly reduced cardiac apoptosis compared with the diabetic control group.

Combined crocin supplementation and treadmill exercise improved inflammatory cytokines and antioxidant-related molecular alterations in the cardiac tissue of HFD/STZ-induced diabetic rats by reducing TNF-α levels and increasing NRF2 protein levels and miR-23b expression. Although the combined intervention showed favorable effects compared with individual treatments, further studies are required to determine whether this combination provides synergistic benefits.