LIPUS promotes stem leydig cells proliferation by up-regulating Wnt5a expression and delays male aging

This study aims to explore the role and mechanism of low-intensity pulsed ultrasound (LIPUS) in delaying the aging of the male reproductive system by regulating the function of Stem Leydig Cells (SLCs). The in vitro aging model of SLCs induced by D-galactose and the Late-onset hypogonadism (LOH) model of rats were adopted. The effects of LIPUS on the function of SLCs and the reproductive related indicators of rats were systematically evaluated by combining techniques such as flow cytometry sorting, immunofluorescence, Western blot, ELISA and small interfering RNA (siRNA) transfection. The results showed that 50 mW/cm² LIPUS could significantly enhance the proliferation ability of senescent SLCs, reduce the expression of aging markers P21 and P53, decrease apoptosis and promote testosterone secretion. Mechanically, LIPUS activates the β-catenin signaling pathway by up-regulating the expression of Wnt5a, promoting nuclear translocation of β-catenin and the expression of downstream Cyclin D1. This effect can be blocked by Wnt5a siRNA. Animal experiments have shown that LIPUS can alleviate the pathological damage and oxidative stress of testicular tissue, increase the fluorescence intensity of Wnt5a, SLCs and LCs in the testicular interstitial region, raise the level of serum testosterone, and simultaneously improve the testicular index, sperm motility and physical fitness of aging rats. This study demonstrates that LIPUS promotes the proliferation of endogenous SLCs by up-regulating Wnt5a and increases testosterone levels in aging rats, providing a non-invasive and physiological regulatory therapeutic strategy for LOH.