The Heart Tissue Molecular Response to Resistance Training in Comparison to Irisin Injection: A Focus on VEGF Gene/Protein Expression and Correlations with Serum Irisin Levels.

Background: Angiogenesis is crucial in the recovery and maintenance of heart function. Irisin may mediate the cardiac health-promoting impact of exercise training. The aim of this study was to comparatively assess VEGF gene/protein expression in the heart tissue and correlations with serum irisin levels following resistance training, in comparison to exogenous irisin injection.

Methods: Twenty-one NMRI mice were randomly assigned to the three group (n = 7 for each group): control, resistance exercise, and irisin. Exercised mice, for 8 weeks, three sessions per week and four sets of five repeats for each session were considered and mice climbed up a 1-m-height ladder with a slope of 80 degrees with a weight equal to 30% of mouse's body weight fastened to their tails and gradually increased up twofold of body weight. The Irisin group received 100 μg/kg/week irisin for 8 weeks, intraperitoneally. The cardiac expression of the VEGF gene, by real-time PCR, the level of VEGF protein, by IHC (immunohistochemistry) and western blot analysis, and serum irisin concentration, by ELISA, were evaluated.

Results: The expression of the VEGF gene and protein, as well as serum Irisin levels, increased in all experimental mice compared to the control group (P < 0.05). Pearson's correlation coefficient data indicated a positive correlation between the analyzed parameters in each group (P < 0.05 and r > 0).

Conclusions: There appears to be an interaction between resistance exercise and cardiac angiogenesis factors, mediated by irisin. So, irisin could be considered in cardiovascular health interventions, aiming to target specific molecules or pathways.