Metabolic syndrome (MS) is a constellation of risk factors that raise the risk for heart disease and other health problems, such as obesity. The clustering of metabolic abnormality is closely related to oxidative stress and inflammation, as well as the progression of atherosclerosis. Antioxidants are reducing agents which inhibit the oxidation of other molecules and can be used not only to prevent but also to treat health complications of MS and atherosclerosis. They can be ingested in the normal diet, since they are found in many food sources, or in supplement formulations. Herein, we aim to review the literature concerning the effect of antioxidants on MS. We focus on antioxidants with some evidence of action on this condition, like flavonoids, arginine, vitamin C, vitamin E, carotenoids, resveratrol and selenium. Experimental and clinical studies show that most of the above-mentioned antioxidants exhibit a wide range of effects in protecting the human body, especially in MS patients. However, the underlying mechanisms are not fully elucidated for most of these compounds. Also, some of them should be used with caution because their excess can be toxic to the body. In general, antioxidants (especially those present in foods) can be used by MS individuals because of their direct effect on oxidative stress. Additionally, they should be encouraged as part of a nutritional lifestyle change, since this is part of the therapy for all diseases involved in metabolic disorders.

This paper verifies the morphological changes induced by immobilization stress on the kidney of rats by using stereological methods. Fifteen 4-week-old Wistar male rats were randomly assigned to control (n = 7) and stressed (n = 8) groups. Stress stimuli were performed over 5 weeks by immobilization of the rats for 2 h daily in a rigid opaque plastic cylinder that restrained their movements. Increases in the adrenal mass index (p < 0.05) and decreases in serum testosterone levels (p < 0.05) demonstrated the efficacy of the stressor stimuli. Stressed rats presented diminished body weight gain when compared to controls (p < 0.05). The mean values of kidney weight, kidney volume, kidney volume index and glomerular volume density were significantly lower in the stressed group (p < 0.05); nevertheless, no significant difference was found in the cortical/medullar ratio or in the volume-weighted mean glomerular volume. The number of glomeruli per kidney was 45% lower in the stressed group (p < 0.0001), but no change in serum creatinine levels was found. However, the morphological alterations may have serious implications predisposing individuals to renal disease and hypertension in adult life.

The objective of this study was to investigate structural changes in the penile corpus cavernosum of prepubertal chronically stressed rats. Eight Wistar rats were assigned into the stress group (SG) and were submitted to 2 hours of tube restraint daily, from the fourth to the ninth week of life. Another 7 rats were used as the control group (CG). All animals were weighed weekly. At day 64, animals were sacrificed by anesthetic overdose, blood was collected for testosterone concentration by radioimmunoassay, and penis and adrenal were collected. Adrenal mass index and testosterone serum levels were used to assess the efficacy of the stress stimulus. The surface density of connective tissue and smooth muscle fibers of corpus cavernosum were measured on Masson trichromic—stained slices. Picrosirius red—stained slices were assessed under polarized light for different types of collagen. The Student's t test was applied for mean comparisons, with P < .05 considered significant. Testosterone serum concentrations decreased and adrenal mass index increased, confirming the effectiveness of the stress protocol. Smooth muscle fibers of corpus cavernosum decreased from 14.07% (CG) to 8.98% (SG) (P = .02), and connective tissue increased from 53.66% (CG) to 64.47% (SG) (P = .01). Also, there was a higher level of type I collagen in the SG animals compared with the CG. Stress stimuli induced structural changes in the corpus cavernosum of rats suggestive of penile fibrosis, which may play a role in erection dysfunction.

We assessed reproductive and testicular function in adult rats after testicular torsion created before, during and after puberty, and with vs without resveratrol or arginine treatment. Age matched rats were divided into groups, including simulated surgery without testicular torsion, 720-degree testicular torsion for 4 hours, testicular torsion with resveratrol treatment and testicular torsion with arginine treatment. To study reproductive function at age 12 weeks each rat mated with 3 females. The males were sacrificed at age 14 weeks. Spermatozoids were collected from the epididymal tail and evaluated for concentration, motility and viability. Testicular samples were collected for morphological analysis. Reproductive function was not altered by testicular torsion but antioxidants improved potency. Compared to sham operated and contralateral samples all spermatozoid parameters from testicular torsion samples were inferior. Resveratrol and arginine did not improve spermatozoid quality or quantity in torsed testes but contralateral samples were improved by each drug. The seminiferous epithelium of rats submitted to testicular torsion during puberty was least affected. Each antioxidant partially to totally prevented the morphological alterations found in rats with untreated testicular torsion. Rats submitted to testicular torsion before puberty that were treated with antioxidants showed the fewest changes. Testicular morphology was altered less in rats when torsion occurred earlier in life, that is during puberty. Treatment with antioxidants improved contralateral spermatozoid production and some fertility parameters. Each antioxidant also prevented testicular morphology alterations after testicular torsion. Prepubertal rats benefited most from antioxidant treatment.

The objective of this study was to investigate the effects of chronic stress on the testes of prepubertal and adult rats and to evaluate whether any alterations could be reversed when stress induction is ended. Seventy-six male rats were assigned to eight groups depending on the type of treatment (control or stressed), the age at which stress was initiated (prepubertal or adult), and the time of evaluation (immediate or late). Stress stimuli were applied for 6 weeks. Stressed prepubertal and adult rats evaluated immediately after the last stress stimulus were included in SP-I and SA-I groups, respectively. The late prepubertal (SP-L) and adult (SA-L) groups of stressed rats were evaluated 6 weeks after the last stress stimulus. Age-matched rats were used as controls (CP-I, CA-I, CP-L, and CA-L groups). Application of stress stimuli to rats in the SP-I group resulted in body weight and seminiferous tubule diameter reduction. The rats in the SA-I group also showed several functional (testosterone level and sperm parameter) and morphological (testicular weight and seminiferous tubule diameter) reductions. The rats in the SP-L group showed increased body weight and intertubular compartment volumetric and absolute densities and reduced tubular compartment volumetric density. The rats in the SA-L group presented only reduced sperm viability. Stress stimuli promoted changes in the rats in all the study groups. The testes of the adult rats were the most affected by chronic stress. However, the stressed adult rats recovered well from the testicular alterations.

Keywords: Hormone Replacement Therapy; Prostate; Orchiectomy; Hypogonadism