The Effect of 16 weeks of intense endurance training on right ventricle structure in male Wistar rats

long-term high intensity endurance training might be associated with an increased risk of cardiac fibrosis. The aim of this study was to determine whether long-term and high intensity endurance training can lead to pathological structural changes in the heart of the rats.

Sixteen male Wistar rats (four weeks old) were randomly divided into two groups: control and training. Extreme endurance training was performed on a treadmill (five sessions per week for 16 weeks). After euthanasia, ventricular collagen deposition was quantified by Masson trichrome–stained images method, and PKP2 and TGF-β1 gene and proteins expression were measured by Real Time-PCR and Western blotting, respectively. Data were analyzed by independent t-test at P ≤ 0.05.

the rate of collagen deposition and TGF-β1 gene and protein expression in the right ventricles of the rats were significantly increased. On the other hand, PKP2 gene expression in the training group was significantly decreased, but PKP2 protein expression was decreased in the exercise group and was not statistically significant.

Based on the results of this animal study, cardiac fibrosis and increased expression of desmosomal proteins were observed after intense and prolonged exercise. This suggests that vigorous and prolonged endurance exercise may possibly cause pathological changes in the right ventricle by disrupting the structure of the desmosomes and forming fibrous tissue.