Age-related changes of the prostate gland in the senescence-accelerated mouse.

Aging is of utmost importance in the pathogenesis of the prostate gland (i.e., benign prostate hyperplasia or prostatic carcinoma). The object of this study was to examine the morphological and histological changes of the aging prostate of the so-called senescence-accelerated mouse (SAM). Ventral and dorsolateral lobes of prostate glands of SAM were microdissected into two-dimensional ductal arrays. Gross morphology, ductal branching patterns, and histology were examined in these microdissected specimens. Wet weight and numbers of ductal tips in ventral and dorsolateral prostate glands in senescence accelerated-prone (SA-P) mice were significantly smaller than those of senescence accelerated-resistant (SA-R) mice, although the changes of patterns of gross ductal morphology were virtually identical in these groups. High incidence of stromal hyperplasia with fibrosis and inflammation was observed in the dorsal lobe of the aged SA-P mouse. Atypical glandular epithelial cells and cribriform glandular deformity were observed in the dorsal and lateral lobe of aged SA-P mice. Marked heterogeneity in age-related pathological changes was observed between prostatic lobes. These data suggest that the aging process occurs heterogeneously within the prostate gland, and that SA-P mice may be an important model for the study of age-related changes in the prostate gland.