Unique morphological aspects of the rat ventral prostate gland revealed by vascular corrosion casting

Abstract

BACKGROUND There is growing interest as to the potential role of the prostatic vascular system in mediating the effects of androgenic steroids on growth control of the prostate. Here we describe the use of a vascular corrosion casting technique that enables the visual characterization of the vascular system of the rat ventral prostate and the description of some unique morphological features of the mature rat prostate gland that were never previously observed. METHODS Anesthetized adult male Sprague-Dawley rats were vascularly perfused with a fixative solution and then with a catalyzed methacrylate-based casting solution that was allowed to polymerize in situ. Ventral prostate glands were dissected from these rats and the tissues were subsequently dissolved in a corrosive solution, leaving residual vascular casts. The casts were then examined by scanning electron microscopy for pertinent morphological features. RESULTS Vascular corrosion casts of individual lobes of the mature rat ventral prostate revealed a complex vascular structure that entered into the prostate near the base of the bladder. The morphological correspondence of the prostatic vasculature to the previously described ductal organization of the prostate was readily apparent. Examination of the entire vascular complex (under low-power scanning electron microscopy) revealed three differing surface features of the tissue and suggested that the glandular elements of the ventral prostate were directionally oriented towards a single surface (the anterior-lateral surface). An opposing face (posterior-medial) of the tissue demonstrated some unique spiral vessels, suggesting the need for a potential stretch-compensation mechanism at the prostate surface immediately adjacent to the bladder. CONCLUSIONS Vascular casts of the rat ventral prostate gland reveal the obvious ductal organization of the prostatic parenchyma and demonstrate that these ducts are directionally oriented so that the glands of the prostate (at the distal tips of the ducts) uniformly lie near the anterior-lateral surface of the tissue. Unusual spiral arterioles found proximal to the bladder surface suggest that the rat ventral prostate gland has acquired the means to adapt to an anatomical position adjacent to a tissue (bladder) that acutely varies in size during the micturition cycle. Prostate 39:240–245, 1999. © 1999 Wiley-Liss, Inc.