Effects of Detraining Followed by Aerobic Exercise on Cardiac Stem Cells in Aged Male Rats

Introduction: the regenerative potential of cardiac stem and progenitor cells is affected by aging and detraining, with the c-kit cardiac stem cell expressing the nkx2.5 transcription factor playing a crucial role. exercise is known to enhance organ regeneration during aging, but the mechanisms involved in new cardiomyocyte formation during physiological cardiac remodeling remain unclear. material & methods: eighteen aged wistar rats (~440g) were divided into three groups: control (co), aerobic training (at) (5 days per week, 50-75% of maximum speed) for six weeks, and detraining (dt) for four weeks. rt-pcr analysis determined nkx2.5 gene expression, while immunohistochemical staining identified c-kit-positive and ki67-positive cardiac progenitor cells. results: in heart tissue, c-kit and ki67 values significantly differed between the control–training (p=0.001) and training-detraining (p=0.001) groups but not between the control and detraining groups for c-kit (p=0.502) and ki67 (p=0.475). nkx2.5 exhibited a significant difference between control-training (p=0.001), training-detraining (p=0.001), and control-detraining (p=0.006). conclusion: exercise increased the proliferation of heart stem cells, activating c-kit differentiation and elevating nkx2.5 expression, thereby delaying the effects of aging. however, detraining significantly impacted heart stem cell function, emphasizing the importance of sustained exercise for optimal cardiac health.