Quantitation of apoptotic activity following castration in human prostatic tissue in vivo

BACKGROUND: Androgen deprivation induces apoptosis in the prostate. Representative data, quantitating apoptotic activity in human prostatic epithelium following androgen ablation, are lacking. METHODS: Human prostatic tissue was grafted beneath the renal capsule of intact male athymic mice and allowed to become established. The mice were castrated and specimens were harvested on post-castration day 0, 1, 2, 3, 4, 5, 7, 8, 9, 10, 14, 17, 18, and 21. Tissue was immediately fixed and apoptotic epithelial nuclei were identified. RESULTS: The percentage of terminal deoxynucleotidyl-transferase-mediated dUTP nick end-labeling (TUNEL) positive epithelial cells increased from a baseline of 0.026%, peaked on post-castration day 3 (1.54%), and returned to baseline by day 21. Mathematical analysis predicted that the observed apoptotic activity account for the loss of 87% of prostatic epithelial cells in 3 weeks. CONCLUSIONS: Post-castration apoptosis in human prostatic epithelium was low but was sufficient to account for the loss of nearly 90% of epithelial cells.