Tanise S. Pês

Resveratrol improves sperm motility, prevents lipid peroxidation and enhances antioxidant defences in the testes of hyperthyroid rats.

Hyperthyroidism may lead to a loss of sperm motility and an increase in oxidative stress (OS) in testes and may cause male reproductive disorders. Thus, the use of compounds with antioxidant properties may be a strategy for preventing these disorders. The effect of resveratrol (RSV) on sperm motility and on variables of the antioxidant status in the testes of rats with triiodothyronine-induced hyperthyroidism (100μg/kg) was investigated. Hyperthyroid rats presented lower sperm motility, higher levels of lipid hydroperoxides and thiobarbituric reactive substances, lower catalase and glutathione peroxidase activities and higher glutathione-S-transferase activity in their testes than control animals. RSV treatment (1mg/kg and 10mg/kg) was able to prevent these effects in the hyperthyroid rats and had no effect in the control animals. In conclusion, RSV might be a strategy for therapeutic intervention to preserve sperm motility and to prevent OS in testes, preserving testicular function in those with hyperthyroidism.

Myrcia sylvatica essential oil mitigates molecular, biochemical and physiological alterations in Rhamdia quelen under different stress events associated to transport

The effects of pre-transport handling and addition of essential oil of Myrcia sylvatica (EOMS) during transport on stress pathways activation in Rhamdia quelen were investigated. Fish (n=400, 25.2±2.9g) were captured in production ponds and transferred to 100-L tank (density 100g L-1). After 24h, 10 fish were sampled (before transport group). The remaining fish were placed in plastic bags (n=30 or 32 fish per bag, density 150g L-1) containing 5L of water (control), ethanol (315μLL-1, vehicle) or EOMS (25 or 35μLL-1), in triplicate, transported for 6h and sampled (n=10 animals per group). Indicators of stress and metabolism, as well as mRNA expression of brain hormones were evaluated. Previously, full-length cDNAs, encoding specific corticotropin-releasing hormone (crh) and proopiomelanocortins (pomca and pomcb), were cloned from whole brain of R. quelen. Crh expression increased after 24h of capture and handling, whereas cortisol and glucose plasmatics enhanced their values in the control group. Transport with EOMS reduced plasma cortisol and lactate levels, while ethanol and EOMS groups increased Na+/K+-ATPase gill activity compared to control. Gene expression of crh, pomcb, prolactin and somatolactin mRNAs were lower after transport with EOMS compared to control. EOMS was able to mitigate the stress pathways activation caused by transport, maintaining a balance in body homeostasis. Thus, EOMS is recommended as sedative in procedures as transport and the pre-transport handling requires greater attention and use of tranquilizers.

N-acetylcysteine protects the rat kidney against aspartame-induced oxidative stress.

Long-term intake of aspartame at the acceptable daily ingestion dose causes oxidative stress in the rat kidney through the dysregulation of glutathione homeostasis. N-acetylcysteine (NAC) provides the cystein required for the production of GSH, being effective in treating disorders associated with oxidative stress. The aim of this research was to investigate the effects of NAC on the aspartame-induced oxidative stress in the rat kidney. The animals received aspartame by gavage for six weeks (40mg/kg). From the 5th week, NAC (1mmol/kg, via intraperitoneal) was injected for two weeks. Then, they were anaesthetized for blood sample and euthanized for the kidney collection. The blood was centrifuged at 1800g for 15min and the serum was separated for creatinine measurement. The tissue was homogenized in 1.15% KCl buffer and centrifuged at 700g for 10min at 4°C. The supernatant fraction obtained was used to the measurements of oxidative stress biomarkers. The creatinine levels were enhanced in the serum of aspartame-treated rats. NAC caused a reduction in the thiobarbituric acid reactive substances, lipid hydroperoxides, carbonyl protein and hydrogen peroxide levels, which were increased in the kidney of aspartame-treated animals. Additionally, NAC caused an elevation in the glutathione peroxidase and glutathione reductase activities, total glutathione, ascorbic acid, and total reactive antioxidant potential levels, which were decreased in the kidney of aspartame-treated rats. In conclusion, NAC may be useful for the protection of the rat kidney against aspartame-induced oxidative stress.

Resveratrol prevents oxidative damage and loss of sperm motility induced by long-term treatment with valproic acid in Wistar rats

Valproic acid (VPA) is a drug widely use for the treatment of epilepsy in both children and adults. Evidence suggests that long-term use of VPA may lead to an impairment in the male reproductive function. Oxidative stress is considered to play a major role in VPA associated toxicity. In the present work, we demonstrated that the natural antioxidant compound resveratrol (RSV) can be use to prevent VPA oxidative damage. Wistar rats treated with VPA (400mgkg(-1)) by gavage for 28days showed decrease in sperm motility accompanied by increase in oxidative damage to lipids and proteins. Additionally, VPA administration leaded to depletion of reduced glutathione and decrease in total antioxidant potential in testes and epididymides of Wistar rats. The co-administration of RSV (10mgkg(-1)) efficiently prevented VPA pro-oxidant effects. In summary, RSV was shown to protect the reproductive system from the damage induced by VPA. Altogether, our data strongly suggests that RSV administration might be a valuable strategy to minimize reproductive impairment in patients requiring long-term VPA treatment.