Angiogenic and tissue remodeling factors in the prostate of elderly rats submitted to hormonal replacement

The influence of senescence and hormone replacement on the onset of pathologic processes in the prostate is not yet fully understood. The aim was to identify the immunoreactivity and protein levels of molecules involved in cell proliferation, tissue remodeling and angiogenesis in the ventral prostate of elderly rodents following hormonal replacement. Male Sprague-Dawley rats were separated into one Young group (4-months old), treated with peanut oil (5 mL kg(-1) , s.c.), and six Senile groups. The senile rats (10-months old) were subdivided into: Senile group (SEN) (5 mL kg(-1) peanut oil, s.c.); Testosterone group (TEST) (5 mg kg(-1) testosterone cipionate, s.c.); Estrogen group (EST) (25 µg kg(-1) 17β-estradiol, s.c.); castrated group (CAS) (surgical castration); castrated-testosterone group (CT) (same treatment as CAS and TEST groups); and castrated-estrogen group (CE) (same treatment as CAS and EST groups). After 30 days, samples of the ventral prostate were harvested for analyses of insulin-like growth factor-1 receptor (IGFR-1), matrix metalloproteinase-9 (MMP-9), vascular endothelial growth factor (VEGF) and endostatin features. IGFR-1 and MMP-9 showed increased protein levels and epithelial immunolabeling both after hormonal replacement and castration. Increased VEGF levels and reduced endostatin were verified in the SEN group. Hormonal therapy and castration led to a higher increase of VEGF, especially in the EST, CAS, and CE groups. Endostatin increased mainly in the TEST and CT groups. Hormonal therapy in senescence generated a reactive microenvironment characterized by the increase of mitogenic and tissue remodeling factors and by the imbalance of angiogenesis, which possibly compromised organ function and predisposed toward glandular disorders.