Neonatal maternal separation causes decreased numbers of sertoli cell, spermatogenic cells, and sperm in mice

Neonatal maternal separation is an experimental model used to evaluate the effects of toxic stress in neonates, or early life stress. Although various physiological and psychological stresses during childhood have been reported, the effects of neonatal maternal separation on the male reproductive system remain unclear. Therefore, the present study evaluated the effects of neonatal maternal separation on the male reproductive system. In neonatal male ICR mice, maternal separation was performed for 0.5, 1, 2, and 4 hours/day, from postnatal day 1 to 10. At 10 weeks of age, the neonatal maternal separation mice exhibited decreases in both testicular weight and epididymal sperm number, along with various testicular morphological changes involving germ cells, Sertoli cells, and interstitial cells. Notably, neonatal maternal separation mice showed decreased numbers of Sertoli cells. Animals subjected to 0.5-, 1-, and 2-h/day neonatal maternal separation exhibited decreases in serum levels of testosterone but not in those of gonadotropin (luteinizing hormone and follicle-stimulating hormone). Together, these data showed that neonatal maternal separation in male mice causes decreased Sertoli cell numbers following puberty, resulting in subsequent decreased spermatogenic activity.