Spontaneous hyperplasia of the ventral lobe of the prostate in aging genetically hypertensive rats

Recent studies have shown that the prostatic autonomic innervation takes pa rt in its homeostasis and growth. Other works showed that spontaneously hyp ertensive rats (SHR) show excessive sympathetic activity, accompanied by lo wer urinary tract symptoms, increased growth capacity of prostatic stromal cells, and increased levels of androgens and their receptors. Furthermore, young SHR were reported to present incipient stages of benign prostatic hyp erplasia (BPH). The aim of the present study was to examine whether this st rain indeed develops spontaneous BPH with age, and can thus serve as a genu ine natural model for this disorder. For this purpose, ventral lobes of pro states of one-year-old, male SHR and their normotensive counterparts, Wista r Kyoto (WKY) rats, were examined histopathologically, and the degree of hy perplasia was evaluated according to a score-chart protocol (histoscore). S HR exhibited severe adenomatous spontaneous BPH, characterized by piling-up of epithelial cells, with papillary formations, accompanied by a mild incr ease in the amount of fibrocytes and smooth muscle cells in the stroma. Thi s was reflected by histoscore values of 38 +/- 2. Thickening of prostatic a rterioles also was noted, as well as mild chronic inflammatory exudate. WKY rats did not show any of these features of BPH despite their age (histosco re 17 +/- 3, significantly different from that of SHR). We conclude that SH R can serve as a rodent model for the spontaneous development of BPH with a ge, most probably due to the excessive neuroendocrine activity characterist ic of this rat strain.