Endothelial-related gene expression profile of muscle adaptation to high-intensity interval training in arterial hypertension

Hypertension and aging are associated with endothelial dysfunction in skeletal muscle, potentially compromising exercise capacity. Although high-intensity interval training (HIIT) has been proposed as an effective non-pharmacological strategy for individuals with hypertension, its effects on endothelial-related markers in aging skeletal muscle remain unclear This study investigated the impact of HIIT on endothelial-related gene expression in hypertensive aging rats. Twenty male 12-month-old spontaneously hypertensive rats were assigned to sedentary (n = 10) or trained (n = 10) groups. The training protocol (50 min/day, 5 times/week) was performed for 8 weeks, on a treadmill adapted for rodents. Gene expression of nitric oxide synthase 3 (NOS3), vascular endothelial growth factor (VEGF), endothelin-1 (EDN1), and phosphoinositide-3-kinase regulatory subunit 2 (PIK3R2) was assessed by reverse transcription quantitative polymerase chain reaction and by reanalysis of transcriptomic datasets available in the Gene Expression Omnibus (GSE109657 and GSE163356). Eight weeks of HIIT reduced blood pressure and improved physical performance, without altering the expression of NOS3, VEGF, EDN1, and PIK3R2 in the soleus and diaphragm muscles. These findings are consistent with an independent transcriptomic dataset from vastus lateralis biopsies of healthy subjects performing HIIT protocols (4 times/week for 6 weeks); however, changes were identified in NOS3, VEGF, and PIK3R2 genes in the vastus lateralis muscle after an HIIT protocol performed 3 times/week for 3 weeks. Collectively, the results indicate that HIIT improves functional capacity and blood pressure regulation in hypertensive aging rats, without concomitant changes in endothelial-related gene expression. These results are comparable with those found in healthy individuals undergoing a similar period of HIIT.