Morphometric analysis of the fate of secretory epithelial cells in the ventral lobe of the rat prostate during massive apoptosis

ABSTRACT

Orchiectomy causes marked, rapid involution of the prostatic secretory epithelium. Concurrently, macrophages, which in normal glands are small and rarely occur at the base of the secretory epithelium, increase in size and number. Apoptotic cells are engulfed by companion epithelial cells and also by macrophages. In secretory cells and macrophages, dense bodies progressively increase in number and store membranes derived from dead cells of the secretory epithelium. In this work, we examined the contributions of the various routes of disposal of demised secretory epithelial cells of the rat prostate, induced to enter in apoptosis by retrieval of androgen. Specifi cally, we sought to determine how much membrane surface area derived from apoptotic cells of the secretory epithelium could be stored in dense bodies, and how these data compared with the disposal of dead cells via the glandular lumen. Glands from unoperated controls (day 0) and from rats examined 12 h and 1, 2, 3, 4, 5, 6, 7, 8, and 9 days after orchiectomy were studied morphometrically. The total membrane surface area of rough and smooth endoplasmic reticulum, Golgi apparatus, mitochondria and vesicles declined from 6.75 x 103 ìm2 in non-castrated rats to 1.12 x 103 ìm2 nine days after castration. Similarly, the total surface area of the secretory epithelium decreased from 10.6 x 1011 ìm2 in non-castrated rats to 0.204 x 1011 ìm2 nine days after castration. Geometrical models revealed that 1 ìm3 of dense body accommodated at least 142 ìm2 of myelin-like membrane surface area. Three to four days after castration, the total volume of intramacrophage dense bodies peaked (~5 x 106 ìm3) and represented 1-2% of the volume of intraepithelial dense bodies (~4 x 108 ìm3). The minimum membrane surface area that could be stored in dense bodies of the secretory epithelium on post-castration days 0, 1, 2, 3, 4 and 9 was 1.4%, 9%, 16%, 23%, 28% and 44%, respectively, of the total membrane surface area of the...