Nitric oxide reduces oxidative damage induced by water stress in sunflower plants

Drought is one of the main environmental constraints that can reduce plant yield. Nitric oxide (NO) is a signal molecule involved in plant responses to several environmental stresses. The objective of this study was to investigate the cytoprotective effect of a single foliar application of 0, 1, 10 or 100 µM of the NO donor sodium nitroprusside (SNP) in sunflower plants under water stress. Water stressed plants treated with 1μM SNP showed an increase in the relative water content compared with 0 μM SNP. Drought reduced the shoot dry weight but SNP applications did not result in alleviation of drought effects. Neither drought nor water stress plus SNP applications altered the content of photosynthetic pigments. Stomatal conductance was reduced by drought and this reduction was accompanied by a significant reduction in intercellular CO2 concentration and photosynthesis. Treatment with SNP did not reverse the effect of drought on the gas exchange characteristics. Drought increased the level of malondialdehyde (MDA) and proline and reduced pirogalol peroxidase (PG-POD) activity, but did not affect the activity of superoxide dismutase (SOD). When the water stressed plants were treated with 10 μM SNP, the activity of PG-POD and the content of proline were increased and the level of MDA was decreased. The results show that the adverse effects of water stress on sunflower plants are dependent on the external NO concentration. The action of NO may be explained by its ability to increase the levels of antioxidant compounds and the activity of ROS-scavenging enzymes.

Spermatic and testicular damages in rats exposed to ethanol: Influence of lipid peroxidation but not testosterone

Chronic consumption of ethanol causes morphological and physiological changes in the reproductive system of mammals. Vitamin C has an antioxidant role in organisms by neutralizing the ROS (reactive oxygen species) produced by oxidizing agents and this vitamin has an important function in the male reproductive system. The aim of this study was to evaluate whether vitamin C could prevent or attenuate the alterations in the male reproductive system caused by ethanol consumption. To test this hypothesis, male rats were divided into three experimental groups and treated by gavage for 63 days. The ethanol (E) and ethanol +vitamin C (EC) groups received 2 g/kg of ethanol (25% v/v) daily. In addition to ethanol, the EC group received vitamin C at a dose of 100 mg/day, diluted in water. The control group (C) received only the vehicle. On the 64th experimental day, the animals were anesthetized and euthanized, and blood was collected for plasmatic hormonal analysis. The testis, epididymis, vas deferens, and seminal vesicles were removed and weighed. Sperm from the vas deferens was submitted to morphological and motility analysis. The testis and epididymis were used for oxidative stress and histopathological analysis, sperm count, morphometric analysis of the testis, and stereological analysis of the epididymis. The results showed that vitamin C has a protective effect in the testes of adult male rats, entirely normalizing the parameters of sperm count, spermatogenesis kinetics, lipid peroxidation levels, and sperm motility, as well as partially normalizing the histopathological damage in the testis, epididymis, and sperm morphology. Thus, we concluded that lipid peroxidation is a major mechanism by which ethanol affects the testes and sperm, whereas no plasmatic testosterone alterations were found.

Alterations to oxidative stress markers in dogs after a short-term stress during transport

While methods to evaluate antioxidant capacity in animals exist, one problem with the models is induction of oxidative stress. It is necessary to promote a great enough challenge to induce measurable alterations to oxidative parameters while ensuring the protocol is compatible with animal welfare. The aim of the present study was to evaluate caged transport as a viable short-term stress that would significantly affect oxidative parameters. Twenty adult Beagle dogs, maintained on the same diet for 60 d prior to the transport, were included in the study. To simulate the stress, the dogs were housed in pairs in transport cages (1·0 m × 1·0 m × 1·5 m), placed on a truck coupled to a trailer and transported for a period of 15 min. Blood collection was performed immediately before and again 3 h after the transportation to evaluate oxidative parameters in blood serum, including thiobarbituric acid reactive substances (TBARS), total antioxidant capacity (TAC), sequestration activity of the radical 2,2-diphenyl-1-picryl-hydrazyl (DPPH•), protein carbonylation (PC), total sulfhydryl groups (SH), alpha-tocopherol (αToc) and retinol (Ret). PC, SH and αToc were not significantly changed in the study; however, TBARS, TAC and DPPH increased, whereas Ret decreased after the transport. Although the lack of a control group of dogs not submitted to transport is a limitation to be considered, we conclude that the transport model is effective in inducing an antioxidant response in dogs and relevant blood parameters show sensitivity to this proposed model.

The oxidation of p-phenylenediamine, an ingredient used for permanent hair dyeing purposes, leads to the formation of hydroxyl radicals: oxidative stress and DNA damage in human immortalized keratinocytes

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estratégias para minimização do estresse oxidativo em sistemas de produção in vitro de embriões bovinos destinados à vitrificação

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Modulação da doença periodontal por curcumin modificado quimicamente. Estudo de dose-resposta em roedor

Pós-graduação em Odontologia - FOAR