Vascular anatomy of the rat ventral prostate.

The rat ventral prostate gland is a model tissue to study the effects of androgenic steroids on prostate cells. Recent reports suggest that the prostatic vascular system is a primary target of androgen action in this tissue. In order to better understand how the vascular system of the ventral prostate supports the tissue in an androgenically normal adult male rat we utilized a variety of microscopic imaging techniques to more fully characterize its structural anatomy and its interaction with other prostatic cell types. Vascular corrosion casts were produced from the mature ventral prostate glands of rats. These casts were analyzed by scanning electron microscopy (SEM) to describe gross and fine details of the prostate vascular anatomy. Fixed thin sections of ventral prostates were immunostained with antiFactor XIII and analyzed by light microscopy for the presence of capillary elements within the prostatic glands. Other sections were directly analyzed by transmission electron microscopy (TEM) to describe the anatomical relationship between the capillaries and the prostatic ducts and their associated glands. The rat ventral prostate is supplied with blood by branches of the inferior vesical artery which enters the apex of the tissue from the base of the urinary bladder. Visualization of the prostatic vascular network under SEM shows that this major vessel is found on the posterior-medial surface of the tissue (closest to the bladder). This surface also has numerous serpentine vessels that appear to facilitate a stable blood supply to the prostate in accommodation of urinary bladder distension. Examination of the opposing surface of the casts allowed a crude description of the structure of the prostatic ductal system with the distal tips of the ducts (containing the prostate glands) oriented towards the anterior-lateral surface of the tissue. On this surface, one can discern a series of adjacent basket-shaped vascular structures of distributing arterioles that supply a dense complex of fine capillaries to the glands. Analysis of the interface of the prostatic ductal system with its vascular elements by light microscopy and TEM shows that some capillaries lie immediately adjacent to the basement membranes of the glands while others can be found interspersed within the myofibroblast layer surrounding the ducts and glands. Veins accompany the arteries and combine with the superior vesical before entering the common iliac vein. This study gives a comprehensive and detailed view of the microvasculature of the rat ventral prostate gland. The findings here will provide the basis for future experiments to evaluate how the ventral prostate vascular system changes in response to androgenic manipulation and to other pathological conditions.