Investigating changes in angiogenesis, tissue hypoxia and Calcineurin of cardiac tissue at immature, mature and old rats following combined training

At the cellular level, the cardioprotective effects of exercise on the heart tissue are different at various ages. The aim of this study is to investigate the changes in angiogenesis (VEGF), tissue hypoxia (HIF-1) and calcium ion flow (Calcineurin) in the heart tissue of immature, mature and old rats following combined training.

Thirty male Wistar rats divided in three age groups of 2 weeks, 8 weeks and 24 months (10 each group) and each age group was divided into two control and exercise training groups (5 each group). In the combined training group, animals performed one day of resistance training and one day of aerobic training for 6 weeks. The amount of overload in the resistance training program was determined based on the body weight of the animals from 30% in the first week to 120% body weight in the last week. For aerobic training, the intensity of training increased from 50% of maximum speed in the first week to 80% in the last week. After 6 weeks of training, sacrificed animals and heart tissue were removed to measure VEGF, HIF-1 and Calcineurin factors by RTPCr method. To analyze data, the statistical method of one-way analysis of variance was used with significance P≤0.05. 

The group of exercise training (8-week) showed higher levels of VEGF gene expression in heart tissue compare to the control group (8-week control) (P=0.020). However, there was no significant difference in VEGF gene expression between training groups in three age groups (P>0.05). Also, there was no significant difference between the control and training groups in each age group and between the training groups in the three age in the expression of cardiac HIF-1 and Calcineurin gene (P>0.05).Discussion and

Exercising at young age has more favorable cellular effects (especially the positive regulation of angiogenesis factor). Therefore, in order to have a good aging period, it was suggested to do regular resistance-aerobic exercises from a young age.