Apoptosis and Proliferation of Human Testicular Somatic and Germ Cells during Prepuberty: High Rate of Testicular Growth in Newborns Mediated by Decreased Apoptosis

Programmed cell death and proliferation are evolutionary conserved processes that play a major role during normal development and homeostasis. In the testis, during the fetal and newborn periods, they might determine final adult size and fertility potential. In the present study, we have measured the relative number of testicular cells in apoptosis and in active proliferation in the seminiferous cords and in the interstitium, at different age periods of prepubertal testicular development in humans. Testes from 44 prepubertal subjects without endocrine and metabolic abnormalities were collected at necropsy. They were divided in three age groups (Gr): Gr 1, newborn (1- to 21-d-old neonates), n = 18, mean (±sd) age 0.3 ± 0.23 months; Gr 2, post natal activation (1- to 6-month-old infants), n = 13, mean age 3.93 ± 1.90 months; and Gr 3, early childhood period (1- to