Neonatal exposure to high d-galactose affects germ cell development in neonatal testes organ culture

Excess exogenous supplementation of d -galactose ( d -gal), a monosaccharide and reducing sugar, generates reactive oxygen species (ROS), leading to cell damage and death. ROS accumulation is critical in aging. Therefore, d -gal-induced aging mouse models are used in aging studies. Herein, we evaluated d -gal’s effect on neonatal testis development using an in vitro organ culture method. Mouse testicular fragments (MTFs) derived from neonatal testes (postnatal day 5) were cultured with 500 mM d -gal for 5 days. d -gal-treated MTFs showed a significantly increased and decreased expression of undifferentiated and differentiated germ cell markers, respectively, with a substantial reduction in meiotic cells. In d -gal-exposed MTFs, expression levels of Sertoli cell markers (Sox9 and Wt1) increased, while those of StAR and 17β-HSD3, whose expressions are abundant in d -Gal treated adult Leydig cells, decreased. Additionally, the enzyme 3 β-HSD1, essential for steroidogenesis in Leydig cells, was significantly reduced in d -gal-exposed MTFs compared to that in controls. d -gal significantly increased the expression of Bad, Bax, and cleaved caspase-3 and -8. Via oxidative stress in MTF. Overall, d -gal negatively regulates germ cell and Leydig cell development in neonatal testes through pro-apoptotic mechanisms and ROS.