RESUMO
The aim of this study was to investigate the effects of castration and testosterone supplementation on nitroso-redox status, cardiac metabolism markers, and S100 proteins expression in the heart of male rats. 50 male Wistar rats were randomized into five groups with ten animals each: group 1: control intact (CON); group 2: sham operated (Sh-O); group 3: sesame oil-treated rats (S-oil); group 4: gonadoectomized (GDX); and group 5: gonadoectomized rats treated with testosterone (GDX-T) for 8 weeks. Our results showed myofibrillar weaving, apoptosis, inflammation, and fibrosis (as reflected by increased activity of MMP 9 and MMP 2) in the heart of gonadoectomized rats. Testosterone supplementation restored the normal structure of the heart. In addition, a state of nitroso-redox imbalance was observed in the heart of castrated rats with increased NO (425.1 ± 322.8 vs. 208 ± 67.06, p Ë 0.05) and MDA (33.18 ± 9.45 vs. 22.04 ± 7.13, p Ë 0.05) and decreased GSH levels (0.71 ± 0.13 vs. 1.09 ± 0.19, p = 0.001). Testosterone treatment leads to a re-establish of only NO levels (425.1 ± 322.8 vs. 210.4 ± 114.3, p > 0.05). Markers of cardiac metabolism showed an enhancement of LDH activity (12725 ± 4604 vs. 5381 ± 3122, p Ë 0.05) in the heart of castrated rats. This was inversed by testosterone replacement (12725 ± 4604 vs. 5781 ± 5187, p Ë 0.05). Furthermore, castration induced heart's accumulation of triglycerides (37.24 ± 6.17 vs. 27.88 ± 6.47, p Ë 0.05) and total cholesterol (61.44 ± 3.59 vs. 54.11 ± 7.55, p Ë 0.05), which were significantly reduced by testosterone supplementation (29.03 ± 2.47 vs. 37.24 ± 6.17, p Ë 0.05) and (47.9 ± 4.15 vs. 61.44 ± 3.59, p Ë 0.001). Cardiomyocytes of castrated rats showed a decreased immunoexpression of S100 proteins compared to control animals. A restoration of S100 proteins immunostaining in cardiomyocyte cytoplasm was observed after testosterone supplementation. These findings confirm the deleterious effects of testosterone deficiency on cardiac function and highlight the involvement of nitric oxide, metalloproteinases 2 and 9, and S100 proteins.