Effects of the chronic use of finasteride and doxazosin mesylate on the histomorphometric characteristics of the prostate: experimental study in rats.

OBJECTIVE: The objective of the present study is to evaluate the histomorphometric characteristics of the prostate of rats submitted to chronic (long-time) treatment with doxazosin mesylate, finasteride and both substances combined. MATERIALS AND METHODS: Four groups of eight rats each were selected for this study and treated with saline solution (control), doxazosin mesylate, finasteride and combination of the drugs, during 10 months. After this time, the prostate was removed, weighed and sent for histological analysis. Prostate sections were stained with Masson trichrome. With an image analyzer, the percentage of smooth muscle, collagen, epithelium, acinar lumen and interstitial space was measured. Also, the minimum, medium and maximum epithelial thickness, number of acini per field, mean acinar area and the presence of papillary projections were evaluated. RESULTS: The mean prostate weight of rats treated with finasteride and combined treatment was lower when compared to the control group (P < 0.05). Prostate from rats treated with finasteride alone had a lower percentage of the epithelial component and a smaller minimum epithelial thickness than the control group (P < 0.05). The number of acini per field in the combined groups was higher than that observed in all other groups (P < 0.05). Also, rats of the finasteride and combined groups presented a reduced number of papillary projections when compared to the other groups (P < 0.05). CONCLUSION: Our study clearly showed the effects of finasteride on prostate tissue, and from a histomorphometric perspective, it was not able to detect any advantage of the combined treatment over the use of finasteride alone.