modulatory effects of swimming training on hypoxia-induced factors in heart tissue of rats exposed to chronic stress

Background: monitoring cardiac, metabolic, neurological, and aging responses to stressors is critical. this study aimed to investigate the effect of swimming training on hif-1α and vascular endothelial growth factor (vegf) levels in heart tissue of rats exposed to chronic stress. methods: to this end, 30 male wistar rats (age: 10 - 12 weeks, weight: 220 ± 20 g) were randomly divided into five equal groups of six rats as follows: (1) con (no treatment for 10 weeks); (2) cs + st (4 weeks of stress, 4 weeks of swimming); (3) st (4 weeks of swimming); (4) cs (4 weeks of stress); (5) cs-time (4 weeks of stress, 6 weeks of no treatment). anxiety-like behaviors were measured by an open field test. heart tissue was immunohistochemically assessed for hif-1α expression using a polyclonal antibody. vascular endothelial growth factor protein levels were also determined using western blot analysis. to analyze the data, kolmogorov-smirnov, one-way anova, and tukey’s post hoc tests were used, and p ≤ 0.05 was considered statistically significant. results: the results showed that chronic mild stress (cms) significantly decreased the hif-1α expression in heart tissue in cs and cs-time groups (p < 0.05). furthermore, the result revealed that swimming training significantly increased the level of hif-1α expression in heart tissue in st and cs + st groups (p < 0.05). although swimming training increased hif-1α levels in the cs + st group after a period of four weeks of cms, these increases were smaller than those observed in st and control groups (p < 0.05). the results from the one-way anova test also demonstrated that the cms significantly downregulated the vegf expression in heart tissue in cs and cs-time groups, whereas swimming training significantly increased its level in st and cs + st groups (p < 0.05). although swimming training increased vegf levels in the cs + st group after a period of four weeks of cms, these increases were smaller than those detected in st and control groups. conclusions: although chronic mild stress had the potential to reduce hypoxia-induced factors in heart tissue, swimming training modified these factors.