Investigating role of the JAK/STAT pathway in cardiac hypertrophy induced by the interval and continuous trainings in adult male rats

The JAK/STAT signaling pathway is activated by an interlacing-6 family of proteins and plays a crucial role in the hypertrophy process. Also, examining the role of this pathway in cardiac physiological hypertrophy derived by endurance training was the ultimate aim of this research.

16 adult male Wistar rats (age,  weeks) were used in this research. The rats were selected at random and assigned to one of two groups: Control and endurance training groups (8 rats in each group). Endurance training groups’ rats trained 8 weeks, 5 days/week. 48 hours after the last session, the rats were euthanized. The cardiac tissue was separated and cardiac hypertrophy was measured through considering heart weight to body weight ratio, left ventricle wall thickness, and cardiomyocytes area. In addition, expression levels of CT1, gp130, JAK2, and STAT3 genes were measured by real-time PCR. Finally, the data were analyzed by the independent t-test. Differences were considered significant at p<0.05.

The endurance training group had a significant increase in the heart weight to body weight ratio compared with the control group (p≤0.0001). Moreover, analyses performed by staining with Hematoxylin Eosin, shown that the training group had significant increases in the thickness of the left ventricle (p≤0.0001). Yet, measuring expression levels of studied genes revealed that there were no significant differences between the training group and the control group expression levels (CT1: P=0.174, gp130: P=0.054, JAK2: P=0.423, STAT3: P=0.062).

Expression profiling in the training group performed after 8 weeks of training, revealed that the expression levels of genes involved in JAK/STAT pathway genes were not changed significantly. These findings suggest that despite the protective role, the JAK/STAT pathway may not play a crucial role in physiological cardiac hypertrophy.