Comparative Light and Electron Microscopic Study of the Human, Dog and Rat Prostate

Stereology was shown in several studies to be a relevant method to study the quantitative amount of tissue and cell compartments of normal and pathological altered prostatic tissue. A morphological comparison of the rat (ventral lobe), dog and human prostate was performed by quantitative morphology. In comparing the light microscopic analysis of the rat ventral prostatic lobe with that of the dog prostate, the volumetric amount of the glandular cells in the dog prostate is two times greater than in the rat (ventral prostatic lobe). In the normal human prostate the volumetric amount of the glandular part was calculated to be 55% of the outer part, respectively 45% in the inner part of the prostate. Regarding the stromal tissue, there is no difference between the dog and the normal human prostate, but a striking difference compared to the rat ventral prostatic lobe, where stromal development seems to be sparse (25%). The quantitative measurements of spontaneous dog and human prostate hyperplasia show that the dog hyperplasia is primarily a glandular disease whereas human benign prostatic hyperplasia reflects more stromal activation. As shown by the electron microscopic measurements in the normal human and dog prostate, there is a similar great volumetric amount of secretory granules. In comparing the data of the rough endoplasmic reticulum, in the rat there is a higher amount than in the normal human and dog prostate. Conversely, the amount of secretory granules is higher in the dog and human prostate than in the rat (ventral prostatic lobe).