Objectives: To determine the percent area density of epithelial and stromal components in the development of prostatic hyperplasia in spontaneously hypertensive (SH) rats.
Methods: The ventral lobes of prostates obtained from male SH rats and their normotensive counterparts, Wistar Kyoto (WKY) rats, were examined histopathologically at 15, 29, 40, and 54 weeks of age (5 SH and WKY rats each at each age group). The degree of prostatic hyperplasia was evaluated with a score-chart protocol, histoscore. The percent area density of epithelium and stroma of the ventral prostate were determined using a computerized image analysis system.
Results: Definite lesions of hyperplastic changes were demonstrated in the ventral prostate of SH rats from 15 to 54 weeks. In comparison with WKY rats, SH rats showed a significantly increased degree of prostatic hyperplasia as reflected by the histoscore values. Furthermore, the histoscore of the ventral prostate of SH rats increased with age (from 21.7 +/- 0.7 at 15 weeks to 26.1 +/- 0.4 at 54 weeks). The percent area density of epithelium and stroma were significantly increased in SH rats, and the ratio of stroma to epithelium ranged from 1:2.94 to 1:3.50 in SH rats but was maintained at 1:1.15 to 1:1.19 in WKY rats during the observation period.
Conclusions: The hyperplastic changes of the ventral prostate may develop with advancing age in SH rats. The development of prostatic hyperplasia may result from both epithelial and stromal proliferation and may be predominantly expressed as a glandular type in SH rats.