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.