ABSTRACT Purpose: To evaluate if late hormonal replacement is able to recover the prostatic tissue modified by androgenic deprivation. Materials and Methods: 24 rats were assigned into a Sham group; an androgen deficient group, submitted to bilateral orchiectomy (Orch); and a group submitted to bilateral orchiectomy followed by testosterone replacement therapy (Orch+T). After 60 days from surgery blood was collected for determination of testosterone levels and the ventral prostate was collected for quantitative and qualitative microscopic analysis. The acinar epithelium height, the number of mast cells per field, and the densities of collagen fibers and acinar lumen were analyzed by stereological methods under light microscopy. The muscle fibers and types of collagen fibers were qualitatively assessed by scanning electron microscopy and polarization microscopy. Results: Hormone depletion (in group Orch) and return to normal levels (in group Orch+T) were effective as verified by serum testosterone analysis. The androgen deprivation promoted several alterations in the prostate: the acinar epithelium height diminished from 16.58±0.47 to 11.48±0.29μm; the number of mast cells per field presented increased from 0.45±0.07 to 2.83±0.25; collagen fibers density increased from 5.83±0.92 to 24.70±1.56%; and acinar lumen density decreased from 36.78±2.14 to 16.47±1.31%. Smooth muscle was also increased in Orch animals, and type I collagen fibers became more predominant in these animals. With the exception of the densities of collagen fibers and acinar lumen, in animals receiving testosterone replacement therapy all parameters became statistically similar to Sham. Collagen fibers density became lower and acinar lumen density became higher in Orch+T animals, when compared to Sham. This is the first study to demonstrate a relation between mast cells and testosterone levels in the prostate. This cells have been implicated in prostatic cancer and benign hyperplasia, although its specific role is not understood. Conclusion: Testosterone deprivation promotes major changes in the prostate of rats. The hormonal replacement therapy was effective in reversing these alterations.

PURPOSE: The aim of this study was to evaluate the expression of leptin and its receptor in histological sections of prostate tumors, and their association with prognostic factors. METHODS: A total of 532 surgical specimens from prostate cancer were studied. After histopathological diagnosis, the samples were included in tissue microarrays containing cores from tumor and non-tumor (benign prostatic hyperplasia) areas. These were immunostained with anti-leptin and anti-leptin-receptor antibodies. Objective and subjective analyses were performed. Student's-t-test and ANOVA were used to compare mean values, and linear regression was used to evaluate the correlation between histological results and prognostic indicators. RESULTS: Leptin receptor expression was reduced in tumors with a positive surgical margin, urethral margin involvement, and seminal vesicles invasion. Further, there was a negative correlation between the expression of leptin receptor in tumor areas and the sum of prognostic factors, suggesting that leptin receptor may predict the aggressiveness of disease. CONCLUSION: Our findings suggest that leptin receptor expression is a potential prognostic factor for PCa. Further investigation is needed to support the use of leptin receptor as a novel biomarker, although leptin itself does not seem to predict the aggressiveness of prostate cancer.