Effect of age, hyperplasia and atrophy on collagen parameters in dog prostates.

The aim of this study was to examine the quantitative parameters of interstitial collagen in the normal and abnormal (hyperplasia, atrophy) prostates of dogs from 6 months to 11 years of age and older. Prostate specimens were fixed in formalin and processed for light microscopy with HE and Sirius Red. A histomorphometric study of collagen was performed using a computer-assisted image analysis system (Quantimet 520). In each section, under the capsule of prostate, except inflammatory tissue, the percentage volume of collagen, the perimeter of collagen area, and the number of fibers in the field of view were determined. The number of collagen fibers in the field of view and the perimeter of interstitial collagen in mature dog prostates decreased with age (p < 0.01). It was determined that the percentage volume moderately correlated with the amount of collagen fibers in the field of view (R = 0.34, p < 0.01) and markedly correlated with the collagen perimeter (R = 0.74, p < 0.01). The percentage volume of collagen in sexually immature dog prostates (up to 7-8 months of age) and in atrophic prostates was 36% and 44%, respectively. In case of hyperplasia, the percentage volume of collagen did not increase.