Purpose: Many adverse effects have been associated with abuse of anabolic-androgenic steroids (AAS), including disorders of the urogenital tract. The objective of this study is to analyze the morphological modifications in the prostate ventral lobe of pubertal and adult rats chronically treated with AAS, using morphometric methods. Materials and Methods: We studied 39 male Wistar rats weighing between 400 g and 550 g. The rats were divided into four groups: (a) control rats, with 105 days of age (C105) (n = 7); (b) control rats with 65 days of age (C65) (n = 9), injected only with the vehicle (peanut oil); (c) treated rats, with 105 days of age (T105) (n = 10) and (d) treated rats with 65 days of age (T65) (n = 13). The treated rats were injected with nandrolone decanoate at a dose of 10 mg.Kg-1 body weight. The steroid hormone and the vehicle were administered by intramuscular injection once a week for eight weeks. The rats were killed at 161 days of age (C105 and T105) and 121 days of age (C65 and T65) and the ventral prostate lobe was dissected and processed for histology. The height of the acinar epithelium, the surface densities of the lumen, epithelium and stroma were observed with X400 magnification using an Olympus light microscope coupled to a Sony CCD video camera, and the images transferred to a Sony monitor KX14-CP1. The selected histological areas were then quantified using the M42 test-grid system on the digitized fields. The data were analyzed with the Graphpad software. To compare the quantitative data in both groups (controls and treated) and the outcomes, Student's t-test was used (p < 0.05 was considered significant). Results: The weight (p < 0.001) and volume (p = 0.004) of the prostate ventral lobe showed differences between C65 and T65 groups and between C105 and T105 groups. The epithelium height showed no difference between groups C65 and T65 (p = 0.8509), but the T105 group showed an increase of 32% compared to C105 (p = 0.0089). Concerning the lumen, surface density presented no difference between C65 and T65 (p = 0.9031) and a decrease of 19% for T105 compared to C105 (p = 0.0061). There was no difference in epithelium surface density between C65 and T65 (p = 0.7375), but it was 51% higher (p = 0.0065) in T105 compared with C105. Regarding stroma surface density, there were no differences between C65 and T65 or between C105 and T105. Finally, there was no difference in collagen pattern between C105 and T105, but T65 showed a predominance of collagen fibers compared to C65. Conclusion: The use of anabolic androgenic steroids in rats promotes structural changes in the prostate. We observed structural changes in the weight, volume and epithelium height of the prostate ventral lobe and a predominance of collagen fibers.

The use of supra-physiological doses of AAS promotes structural changes in the rat penis, by altering the proportions of corpus cavernosum tissues, in both pubertal and adult treated animals.