Avaliação ex vivo da inibição da peroxidação lipídica do estrato córneo promovida por filtros UVB / Ex vivo evaluation of the inhibition of lipid peroxidation of the stratum corneum promoted by UVB filters

O aumento da incidência do câncer de pele está associado à maior exposição à luz solar e a adoção de ações de proteção ao Sol é uma estratégia para minimizar os níveis cumulativos de danos à pele. Os raios ultravioletas (UV), ao alcançarem o tecido cutâneo, podem causar eritema, inflamação, fotoenvelhecimento, formação de rugas e imunossupressão, entre outros, devido à formação de espécies reativas de oxigênio (ERO´s). A formação de ERO´s, como o oxigênio singleto, radical ânion superóxido, peróxido de hidrogênio e radical hidroxil, elevam o risco dos danos foto-oxidativos. O desequilíbrio entre a formação de ERO´s e os mecanismos antioxidantes do organismo desencadeia o estresse oxidativo. Na pele, as ERO´s são as responsáveis pelo dano oxidativo no DNA, proteínas e lipídeos. Identificar e quantificar biomarcadores do estresse oxidativo cutâneo é essencial para a correlação entre os raios UV e seus efeitos. Deve-se isto, em parte, à limitação de métodos para quantificar os parâmetros que são diretamente afetados pela exposição aos raios UV, tais como a peroxidação lipídica. São necessários métodos complementares para avaliação da eficácia de fotoprotetores perante os danos causados por este tipo de estresse. Esta pesquisa projeto compreendeu a avaliação ex vivo da eficácia de filtros solares UVB por meio da quantificação da peroxidação lipídica proveniente do estrato córneo removido por tape stripping. Foram preparados sistemas emulsionados do tipo O/A com os filtros octocrileno, metoxicinamato de octila e salicilato de octila. A caracterização funcional da eficácia fotoprotetora in vitro demonstrou que o filtro octocrileno manteve-se estável, mesmo após exposição solar artificial. Os filtros octocrileno (10% p/p), metoxicinamato de octila (10% p/p) e salicilato de octila (5% p/p) alcançaram, após irradiância, respectivamente, os valores de FPS 5,7 ± 2,1; 4,7 ± 1,5 e 1,0± 0,0. As formulações foram utilizadas na avaliação da eficácia fotoprotetora ex vivo. O método por CLAE, para quantificação da peroxidação lipídica no estrato córneo, possuiu linearidade e demonstrou exatidão e precisão satisfatórias. O estresse pela radiação UV desencadeou a peroxidação lipídica no estrato córneo. Em função do protocolo aplicado, não houve diferenças entre as amostras. A eficácia, com relação à inibição da peroxidação lipídica, foi similar em todas as amostras

The increasing of incidence of skin cancer is associated with greater exposure to sunlight and the adoption of sun protection actions is a strategy to minimize cumulative levels of skin damage. Ultraviolet (UV) rays, when they reach the cutaneous tissue, can cause erythema, inflammation, photoaging, wrinkling and immunosuppression, among other things, due to the formation of reactive oxygen species (ROS). The formation of ROS, such as singlet oxygen, superoxide anion radical, hydrogen peroxide and hydroxyl radical, raise the risk of photooxidative damage. The variation between the formation of ROS and the antioxidant mechanisms of the organism triggers oxidative stress. In the skin, ROS are responsible for oxidative damage in DNA, proteins and lipids. Identifying and quantifying biomarkers of cutaneous oxidative stress is essential for the correlation between UV rays and their effects. This is partially due to the limitation of methods for quantifying parameters that are directly affected by exposure to UV rays, such as lipid peroxidation. Complementary methods are needed to evaluate the effectiveness of photoprotectors because of the damage caused by this type of stress. This research project had the ex vivo evaluation of the efficacy of UVB sunscreens by quantifying the lipid peroxidation from the stratum corneum removed by tape stripping. Emulsified O/A type systems were prepared with the octocrylene, octyl methoxycinnamate and octyl salicylate filters. The functional characterization of photoprotective efficacy in vitro revealed that the octocrylene filter remained stable even after artificial sun exposure. Octocrylene (10% w / w), octyl methoxycinnamate (10% w / w) and octyl salicylate (5% w / w) respectively reached the values of FPS 5.7 ± 2.1; 4.7 ± 1.5 and 1.0 ± 0.0. The formulations were used in the evaluation of ex vivo photoprotective efficacy. The method by HPLC, for quantification of the lipid peroxidation in the stratum corneum, had linearity and demonstrated satisfactory accuracy and precision. UV radiation stress triggered lipid peroxidation in the stratum corneum. Due to the protocol applied, there were no differences between the samples. The efficacy, compared to the inhibition of lipid peroxidation, was similar in all samples

Radioiodine-induced oxidative stress in patients with differentiated thyroid carcinoma and effect of supplementation with vitamins C and E and selenium (antioxidants)

ABSTRACT Objective The objective of this study, in addition to confirming that therapy with 131I causes oxidative stress, was to evaluate the effect of supplementation with vitamins C and E and selenium on this phenomenon by measuring plasma 8-epi-PGF2a, a marker of lipid peroxidation. Subjects and methods Forty patients with thyroid cancer submitted to thyroidectomy, who received 3.7 GBq 131I after levothyroxine withdrawal, were selected; 20 patients did not receive (control group) and 20 patients received (intervention group) daily supplementation consisting of 2000 mg vitamin C, 1000 mg vitamin E and 400 µg selenium for 21 days before 131I. Plasma 8-epi-PGF2a was measured immediately before and 2 and 7 days after 131I. Results A significant increase in plasma 8-epi-PGF2a after 131I was observed in the two groups. The concentrations of 8-epi-PGF2α were significantly higher in the control group before and 2 and 7 days after 131I. The percentage of patients with elevated 8-epi-PGF2α was also significantly higher in the control group before and after 131I. Furthermore, the increase (percent) in 8-epi-PGF2α was significantly greater in the control group (average of 112.3% versus 56.3%). Only two patients (10%) reported side effects during supplementation. Conclusions Ablation with 131I causes oxidative stress which can be minimized by the use of antioxidants.

Oxidative stress in patients with differentiated thyroid cancer: Early effects of radioiodine therapy.

Ionizing radiation in differentiated thyroid cancer (DTC) patients treated with radioiodine (131-I) produces reactive oxygen species (ROS), which could induce oxidative stress with disturbance of redox balance. The aim of this study was to evaluate oxidative stress in DTC patients treated with 3.7 or 5.5 GBq of 131-I using values for serum malondialdehyde (MDA, a marker of oxidative stress), uric acid (to determine antioxidant status) and total antioxidative status (TAS). The study population included 20 DTC patients and 20 healthy controls. Significant differences in MDA concentrations were found between DTC patients before 131-I therapy and control subjects (p = 0.001), while TAS values were similar in both populations (p>0.05). There was a negative correlation between MDA concentrations and TAS in the DTC group before therapy (R2 = 0.2973, p = 0.013). Three days after 131-I therapy, MDA concentrations were higher than the pretreatment values (3.36 ± 1.69 nmol/mL vs. 2.93 ± 1.31 nmol/mL; p = 0.006), while serum uric acid concentrations declined progressively from 341.0 ± 80.39 μmol/L to 304.25 ± 77.25 μmol/L (p = 0.026) in 3 days and 291.2 ± 88.86 μmol/L (p = 0.009) in 7 days after 131-I therapy. There was no dose-dependent effect on MDA, or uric acid concentrations and TAS. Thus, 131-I therapy in DTC patients induced oxidative stress, which was accompanied by a simultaneous and extended reduction in uric acid concentration, but without significant disturbances in TAS. This is the first study that evaluated TAS capacity in DTC patients before and 7 days after 131-I therapy. The relatively stabile TAS values in these patients indicated a good protection from oxidative stress induced by high doses of ionizing radiation.

Evaluation of changes in lipid peroxidation, ROS production, surface structures, secondary metabolites and yield of linseed (Linum usitatissimum L.) under individual and combined stress of ultraviolet-B and ozone using open top chambers.

The individual and interactive effects of supplemental UV-B (sUV-B) (ambient + 7.2 kJ m-2 d-1) and elevated O3 (ambient + 10 ppb) were evaluated under field conditions using open top chambers on two cultivars, Padmini and T-397 of linseed (Linum usitatissimum L.). Mean monthly surface level of O3 concentrations varied from 27.7 ppb to 59.0 ppb during the experimental period. Both UV-B and O3 induced the production of ROS (H2O2 and O2.-), resulting in significant damage of membranes due to lipid peroxidation and electrolyte leakage. Synthesis of secondary metabolites (flavonoids, anthocyanin, lignin and wax) was also enhanced in all the treatments, whereas biomass and yield were reduced. Alterations in frequency of stomata and wax distribution were also observed through scanning electron microscopy (SEM). Cultivar Padmini was found to be more sensitive because of higher damage of membrane vis-a-vis reduction in biomass and seed yield. However, concentrations of flavonoids, anthocyanin, lignin and wax were higher in T-397, suggesting its relative resistance against applied stress. Combined exposure of sUV-B and O3 was less harmful, as compared to their individual treatment. Among the three treatments, O3 was found to be more detrimental for overall growth and sUV-B for economic yield.

Bebida à base de subproduto da uva: efeitos sobre o estresse oxidativo e marcadores de risco de doenças cardiovasculares em mulheres saudáveis / Drink-based byproduct of grapes: effects on oxidative stress and markers of cardiovascular disease risk in healthy women

Introdução: Estudos epidemiológicos sugerem que o consumo de vinho, produtos de uva e outros alimentos contendo polifenóis está associado à diminuição do risco de doenças cardiovasculares. Na produção de vinhos e suco de uva são geradas quantidades expressivas de bagaço residual, que é prejudicial ao meio ambiente. Por outro lado, este subproduto possui alto teor de antioxidantes e de fibras. Objetivo: Produzir uma bebida à base de farinha de bagaço de uva proveniente do processamento de suco de uva (FBSU) e avaliar seus efeitos sobre o estresse oxidativo e marcadores de risco para doenças cardiovasculares em mulheres saudáveis. Métodos: A bebida de FBSU e um suco comercial de uva (usado como controle no estudo in vivo) foram avaliados : sensorialmente por escala hedônica de 9 pontos; composição proximal segundo a AOAC; características físico-químicas; compostos fenólicos totais por Folin, capacidade antioxidante: (a) absorbância de oxigênio radical - ORAC, (b) capacidade antioxidante total - TAS, (c) capacidade de sequestrar o radical DPPH e (d) sistema -caroteno/ácido linoléico. Sujeitos: mulheres saudáveis (n=15) foram randomizadas em um estudo clínico crossover, controlado, com quatro períodos de duas semanas de duração. Após washout, forneceu-se bebida de FBSU e suco de uva comercial, intercalados com outro washout. Quantificou-se triglicérides, colesterol total e suas frações, proteína C-reativa, IL-6, TNF- e MCP-1. A LDL foi submetida à oxidação e em seguida medidos os produtos de peroxidação lipídica. TAS e ORAC do plasma foram determinados. Nos eritrócitos, foram analisadas as enzimas antioxidantes superóxido dismutase (SOD), glutationa peroxidase (GSH-Px) e catalase (CAT). Realizou-se o ensaio cometa nos linfócitos. O consumo das voluntárias foi avaliado por diário alimentar de 3 dias durante a intervenção com a bebida de FBSU, com o suco comercial e no washout...

Introduction: Epidemiological studies suggest that consumption of wine, grape products and other foods containing polyphenols is associated with decreased risk of cardiovascular disease. In the production of wine and grape juice significant amounts of pomace flour are generated, which is harmful to the environment. Moreover, this byproduct is high in antioxidants and fiber. Objectives: To develop a beverage using grape pomace flour (GPF) from grape juice and to evaluate its effect on oxidative stress and inflammatory biomarkers for cardiovascular disease risk in healthy women. Methods: GPF beverage and a commercial grape juice (used as control in the in vivo study) were sensory evaluated using the 9-point hedonic scale and had the proximal composition determined using the AOAC methods; physicochemical characteristics were analysed; total phenolics compound were quantified with the Folin-Ciocalteu reagent; antioxidant capacity was determined by different methods: (a) oxygen radical absorbance capacity assay - ORAC, (b) total antioxidant status - TAS, (c) radical scavenging activity (DPPH) assay, (d) -carotene and linoleic acid system). Fifteen healthy women were randomized in a crossover clinical study, controlled with four periods of two weeks duration. It started with washout, followed by GPF beverage and commercial grape juice, interspersed with another washout. We evaluated triglycerides, total cholesterol and its fractions, C-reactive protein, IL-6, TNF- and MCP-1. The LDL was subjected to oxidation and then measured the lipid peroxidation products. TAS and ORAC of the plasma were determined. In erythrocytes, the antioxidant enzymes superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT) were analyzed. We carried out the comet assay in lymphocytes. We evaluated the dietary intake of volunteers in three separate stages during the intervention with GPF beverage, with commercial juice and washout...

Response to short term ultraviolet stress in the reef-building coral Pocillopora capitata (Anthozoa: Scleractinia)

Coral reefs are impacted by a range of environmental variables that affect their growth and survival, the main factors being the high irradiance and temperature fluctuations. Specimens of Pocillopora capitata Verrill 1864 were exposed to photosynthetically active radiation (PAR) and ultraviolet radiation (UVR) for 32h under laboratory conditions. We examined lipid peroxidation (MDA), antioxidant enzyme activities (SOD, CAT, GPx and GST), chlorophyll a (Chl a), carotenoid pigments (CPs), mycosporine-like amino acids (MAAs), and expulsion of zooxanthellae. Our results revealed that corals exposed to UVR had relatively low levels of carotenoids and antioxidant enzyme activities compared to those exposed to PAR, as well as lower CPs/Chl a ratios. Although MAAs and CPs are rapidly produced as non-enzymatic antioxidants in response to UVR in corals, these were not sufficient, even in the dark phase of the experiment, to mitigate the damage caused by formation of reactive oxygen species (ROS), which caused breakdown of the symbiotic relationship between the zooxanthellae and the host animal to an extent 33 times greater than in the PAR treatment. In this study, it could be possible to distinguish that, parallel to the short-term adjustments, such as the amount of pigment in the algae or the sensitivity of the photosynthetic response reported in other species of coral, P. capitata exhibits at the enzymatic level a series of responses oriented to resist the effects derived from the propagation of ROS and, thus, to adapt to and maintain its reproductive capacity in shallow oceanic environments that commonly exhibit high UVR levels. Nevertheless, as a result of the inappropriate location of the artificial intercommunication structure of the Juluapan Lagoon with respect to the arrecifal area of study and therefore of the tides influence, other variables, such as the changes in short-term in turbidity, sediment inputs, nutrients, temperature and osmolarity, can act in combination and cause irreversible damage. The implementation of a management plan for the coralline reefs of the Mexican Pacific coast is required. Rev. Biol. Trop. 58 (1): 103-118. Epub 2010 March 01.

Los arrecifes de coral se ven afectados por una serie de variables ambientales que afectan su crecimiento y supervivencia, siendo los principales factores la alta irradiación y las fluctuaciones de temperatura. Los especímenes de Pocillopora capitata Verrill 1864 fueron expuestos a radiación activa fotosintéticamente (PAR) y radiación ultravioleta (RUV) por 32h en condiciones de laboratorio. Nosotros determinamos las concentraciones de peroxidación lipídica (MDA), actividades de enzimas antioxidantes (SOD, CAT, GPx y GST), clorofila a (Chl a), pigmentos carotenoides (CPS), aminoácidos tipo micosporina (MAAS), y la expulsión de las zooxantelas. Nuestros resultados muestran que los corales expuestos a los rayos UV presentaban niveles relativamente bajos de carotenoides y actividad de las enzimas antioxidantes en comparación con los expuestos al PAR, así como tasas de CPs/Chl a bajas. Aunque MAAs y CPs se producen rápidamente como antioxidantes no enzimáticos en respuesta a la radiación ultravioleta en los corales, éstos no fueron suficientes, incluso en la fase oscura del experimento, para mitigar los daños causados por la formación de especies reactivas de oxígeno (ROS), lo que provocó una ruptura en la relación simbiótica entre las zooxantelas y el coral con una relación 33 veces mayor que en el tratamiento de PAR. A nivel enzimático, P capitata presentó una serie de ajustes orientados a resistir los efectos derivados de la propagación de ROS y con ello favorecer su adaptación y capacidad reproductiva en ambientes oceánicos caracterizados por altos niveles de UVR.

Ameliorating effects of genestein: study on mice liver glutathione and lipid peroxidation after irradiation

Genistein is a soya isoflavone, which is found naturally in legumes, such as soybeans and chickpeas. Radiation-induced free radicals in turn impair the antioxidative defense mechanism, leading to an increased membrane lipid peroxidation that results in damage of the membrane bound enzyme and may lead to damage or death of cell. Hence, the lipid peroxidation is a good biomarker of damage occurs due to radiation and the inhibition of lipid peroxidation is suggestive of radioprotective action. Glutathione has been shown to protect cells against oxidative stress by reacting with peroxides and hydroperoxides and determines the inherent radiosensitivity of cells. For experimentation, healthy Swiss Albino male mice of 6 -8 weeks old were selected from inbred colony. Genistein was dissolved in dimethyl sulfoxide and then prepared different concentration solutions so that the volume administered intraperitoneally was 0.5 ml. Lipid peroxidation was estimated by the method of Ohkawa and GSH was estimated by the method of Moron. The intraperitoneal administration of optimum dose [200 mg/kg body weight] of Genistein before 24 hrs and 15 minutes of irradiation [8 Gy at a dose rate of 1.02 Gy/min] reverted the increase in lipid peroxidation [by 18.01% +/- 3.05] and decrease of Glutathione [by 62.05% +/- 21.58] caused by irradiation in liver of Swiss albino mice. Statistically analyzed survival data produced a dose reduction factor [DRF] = 1.24. The results indicate that Genistein against radiation effect may pave way to the formulation of medicine in radiotherapy for normal tissue and possible against radiomimetic drug induced toxicity

Radio frequency electromagnetic radiation (RF-EMR) from GSM (0.9/1.8GHz) mobile phones induces oxidative stress and reduces sperm motility in rats

INTRODUCTION: Mobile phones have become indispensable in the daily lives of men and women around the globe. As cell phone use has become more widespread, concerns have mounted regarding the potentially harmful effects of RF-EMR from these devices. OBJECTIVE: The present study was designed to evaluate the effects of RF-EMR from mobile phones on free radical metabolism and sperm quality. MATERIALS AND METHODS: Male albino Wistar rats (10-12 weeks old) were exposed to RF-EMR from an active GSM (0.9/1.8 GHz) mobile phone for 1 hour continuously per day for 28 days. Controls were exposed to a mobile phone without a battery for the same period. The phone was kept in a cage with a wooden bottom in order to address concerns that the effects of exposure to the phone could be due to heat emitted by the phone rather than to RF-EMR alone. Animals were sacrificed 24 hours after the last exposure and tissues of interest were harvested. RESULTS: One hour of exposure to the phone did not significantly change facial temperature in either group of rats. No significant difference was observed in total sperm count between controls and RF-EMR exposed groups. However, rats exposed to RF-EMR exhibited a significantly reduced percentage of motile sperm. Moreover, RF-EMR exposure resulted in a significant increase in lipid peroxidation and low GSH content in the testis and epididymis. CONCLUSION: Given the results of the present study, we speculate that RF-EMR from mobile phones negatively affects semen quality and may impair male fertility.

Rectification of radiation-induced damage in Swiss albino mice by aloe vera leaf extracts [AVE]

From the time immemorial man has been exposed to ionizing radiation from the environment in which he lives. Radiation protection concepts and philosophy have been evolving over the past several decades. The radioprotective of effect of Aloe vera leaf extract [1000 mg /kg b.wt. orally for 15 consecutive days] has been studied against 6 Gy of gamma radiation in the intestine of Swiss albino mice at various post - irradiation intervals viz. 12 hrs, 24 hrs. and 3, 5, 10, 20 and 30 days. Crypt survival, villus length, apoptic cells, mitotic figures and goblet cells in jejunum were studied after irradiation. Irradiaton produced a significant decrease in crypt survival, mitotic figures and villus length; whereas goblet and apoptic cells showed a significant increase from sham irradiated animals. The major changes were observed on day 3 after irradiation. AVE pre-treated irradiated animals resulted in a significant increase in the number of crypt cells, mitotic figures and villus length; whereas the counts of apoptic and goblet cells showed a significant decrease from respective control group at all the autopsy intervals. Irradiated animals resulted in the elevation in lipid peroxidation and a reduction in glutathione activity. On contrary, AVE treatment before irradiation caused a significant depletion in lipid peroxidation and elevation in glutathione activity. The present study suggests the possible radioprotective ability of Aloe vera leaf extract

Radiation induced peroxidative damage: mechanism and significance.

An interest has been generated in free radicals after the discovery of superoxide dismutase. These free radicals cause a number of diseases and are involved in the detrimental effect of ionizing radiation. Efforts have been made to understand their role in damage and death of the cell using lipid peroxidation process. Lipid peroxidation is an important effect of radiation on membranes, which apart from DNA, are critical targets of radiation action. This paper addresses the basic mechanism of radiation induced lipid peroxidation. Various factors, which determine the mode and magnitude of lipid peroxidation, are also discussed. Lipid peroxidation is shown to have importance in understanding the modifications of radiation effects. Efforts are made to show similarities between radiolytic and non-radiolytic lipid peroxidation. Recent findings related to the close link between radiation-induced lipid peroxidation and apoptosis are likely to open new avenues for future research and to develop new approaches for radiomodification of biological effects.

Protective effect of curcumin, ellagic acid and bixin on radiation induced toxicity.

Whole body irradiation of rats (10 Gy as five fractions) found to produce lung fibrosis within 2 months as seen from increased lung collagen hydroxyproline and histopathology. Oral administration of antioxidants curcumin, ellagic acid, bixin and alpha-tocopherol at a concentration 200 mumole/kg body weight significantly reduced the lung collagen hydroxyproline in these animals. In serum and liver lipid peroxidation which were found to be increased by irradiation was reduced significantly by antioxidant treatment. The liver superoxide dismutase and glutathione peroxidase activity were also found to be increased and catalase activity decreased in irradiated control. Superoxide dismutase activity reduced significantly by antioxidant treatment while catalase activity was found to be increased with alpha-tocopherol treatment. The increased frequency of micronucleated polychromatic erythrocytes after whole body irradiation of mice was found to be significantly reduced with antioxidants.

An approach towards understanding the genesis of sunlight-induced skin cancer.

The molecular basis of the sunlight-induced skin carcinogenesis has been elucidated. Of the two ultraviolet components of sunlight that reach the earth's surface the UV-B is known to be carcinogenic but the mode of action of UV-A, the predominant component of sunlight, is ill understood. Using the liposomes as a model system, it has been shown here that UV-A causes dose-dependent lipid peroxidation as estimated by measurements of conjugated dienes, lipid hydroperoxides, malondialdehydes and the fluorescent adducts (Schiff bases) produced by the reaction of MDA with glycine. Direct exposure to sunlight has also been shown to cause dose-dependent lipid peroxidation. The UV-A induced lipid peroxidation has also been shown to be dependent on dose rate. While the sodium formate, dimethyl sulphoxide, superoxide dismutase and EDTA do not have any significant effect, sodium azide, histidine, beta-carotene and dimethylfuran were shown to inhibit significantly the UV-A induced lipid peroxidation, thereby providing significant evidence of the involvement of singlet oxygen (1O2) as the initiating agent. The use of D2O in place of H2O as the liposome dispersing medium enhanced to great extent the UV-A induced lipid peroxidation, thereby lending additional support to the finding that singlet oxygen was the initiating agent. The possible mode of formation of 1O2 on exposure to UV-A was discussed. This study also highlighted the role of environmental factors on the sunlight-induced cutaneous damage. Finally, the relation between lipid peroxidation, DNA damage and carcinogenesis has been discussed in a way to suggest the possible link between sunlight exposure and causation of skin cancer.