Androgen-dependent blood flow control and morphological changes of the capillaries in rat prostate

To clarify the effect of androgens on the microcirculation of the prostate, organ blood flow and ultrastructural features of the capillaries were investigated. In the ventral prostate (VP) of adult Wistar rats, organ blood flow was measured using a laser Doppler flowmetry, and the morphological features of the subepithelial capillaries were investigated and their luminal area was measured using transmission electron microscopy and a computed image analyzer at 1, 2, 3, and 7 days after castration, and 2 days after castration and gradational testosterone supplementation. The capillaries of the VP were classified into three types; oval opened (type 1), intermediate (type 2) and collapsed (type 3). Organ blood flow reduced from 40.5 to 27.7 mL/min/100 g (p < 0.0001) and the luminal area of the capillaries reduced from 13.5 to 4.5 microm2 (p < 0.0001) 2 days after castration. These reductions of the blood flow and the luminal area were gradationally prevented by testosterone supplementation. In the morphological features of the capillary, type 1 had rapidly shifted to types 2 and 3 after castration, and the shift of the capillary type was significantly prevented by the testosterone supplementation. These results clearly demonstrated that the androgen-dependent ultrastructural and morphological features in subepithelial capillaries revealed local microcirculatory conditions correlating the organ blood flow changes in VP.