Effects of propofol on damage of rat intestinal epithelial cells induced by heat stress and lipopolysaccharides

Gut-derived endotoxin and pathogenic bacteria have been proposed as important causative factors of morbidity and death during heat stroke. However, it is still unclear what kind of damage is induced by heat stress. In this study, the rat intestinal epithelial cell line (IEC-6) was treated with heat stress or a combination of heat stress and lipopolysaccharide (LPS). In addition, propofol, which plays an important role in anti-inflammation and organ protection, was applied to study its effects on cellular viability and apoptosis. Heat stress, LPS, or heat stress combined with LPS stimulation can all cause intestinal epithelial cell damage, including early apoptosis and subsequent necrosis. However, propofol can alleviate injuries caused by heat stress, LPS, or the combination of heat stress and LPS. Interestingly, propofol can only mitigate LPS-induced intestinal epithelial cell apoptosis, and has no protective role in heat-stress-induced apoptosis. This study developed a model that can mimic the intestinal heat stress environment. It demonstrates the effects on intestinal epithelial cell damage, and indicated that propofol could be used as a therapeutic drug for the treatment of heat-stress-induced intestinal injuries.

Antioxidant effect of mogrosides against oxidative stress induced by palmitic acid in mouse insulinoma NIT-1 cells

Excessive oxidative stress in pancreatic β cells, caused by glucose and fatty acids, is associated with the pathogenesis of type 2 diabetes. Mogrosides have shown antioxidant and antidiabetic activities in animal models of diabetes, but the underlying mechanisms remain unclear. This study evaluated the antioxidant effect of mogrosides on insulinoma cells under oxidative stress caused by palmitic acid, and investigated the underlying molecular mechanisms. Mouse insulinoma NIT-1 cells were cultured in medium containing 0.75 mM palmitic acid, mimicking oxidative stress. The effects of 1 mM mogrosides were determined with the dichlorodihydrofluorescein diacetate assay for intracellular reactive oxygen species (ROS) and FITC-Annexin V/PI assay for cell apoptosis. Expression of glucose transporter-2 (GLUT2) and pyruvate kinase was determined by semi-quantitative reverse-transcription polymerase chain reaction. Palmitic acid significantly increased intracellular ROS concentration 2-fold (P<0.05), and decreased expression of GLUT2 (by 60%, P<0.05) and pyruvate kinase (by 80%, P<0.05) mRNAs in NIT-1 cells. Compared with palmitic acid, co-treatment with 1 mM mogrosides for 48 h significantly reduced intracellular ROS concentration and restored mRNA expression levels of GLUT2 and pyruvate kinase. However, mogrosides did not reverse palmitic acid-induced apoptosis in NIT-1 cells. Our results indicate that mogrosides might exert their antioxidant effect by reducing intracellular ROS and regulating expression of genes involved in glucose metabolism. Further research is needed to achieve a better understanding of the signaling pathway involved in the antioxidant effect of mogrosides.

Stress-related hormone norepinephrine induces interleukin-6 expression in GES-1 cells

In the current literature, there is evidence that psychological factors can affect the incidence and progression of some cancers. Interleukin 6 (IL-6) is known to be elevated in individuals experiencing chronic stress and is also involved in oncogenesis and cancer progression. However, the precise mechanism of IL-6 induction by the stress-related hormone norepinephrine (NE) is not clear, and, furthermore, there are no reports about the effect of NE on IL-6 expression in gastric epithelial cells. In this study, we examined the effect of NE on IL-6 expression in immortalized human gastric epithelial cells (GES-1 cells). Using real-time PCR and enzyme-linked immunoassay, we demonstrated that NE can induce IL-6 mRNA and protein expression in GES-1 cells. The induction is through the β-adrenergic receptor-cAMP-protein kinase A pathway and mainly at the transcriptional level. Progressive 5′-deletions and site-directed mutagenesis of the parental construct show that, although activating-protein-1 (AP-1), cAMP-responsive element binding protein (CREB), CCAAT-enhancer binding protein-β (C/EBP-β), and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) binding sites are all required in the basal transcription of IL-6, only AP-1 and CREB binding sites in the IL-6 promoter are required in NE-induced IL-6 expression. The results suggest that chronic stress may increase IL-6 secretion of human gastric epithelial cells, at least in part, by the stress-associated hormone norepinephrine, and provides basic data on stress and gastric cancer progression.

Changes in tau phosphorylation levels in the hippocampus and frontal cortex following chronic stress

Studies have indicated that early-life or early-onset depression is associated with a 2- to 4-fold increased risk of developing Alzheimers disease (AD). In AD, aggregation of an abnormally phosphorylated form of the tau protein may be a key pathological event. Tau is known to play a major role in promoting microtubule assembly and stabilization, and in maintaining the normal morphology of neurons. Several studies have reported that stress may induce tau phosphorylation. The main aim of the present study was to investigate possible alterations in the tau protein in the hippocampus and frontal cortex of 32 male Sprague-Dawley rats exposed to chronic unpredictable mild stress (CUMS) and then re-exposed to CUMS to mimic depression and the recurrence of depression, respectively, in humans. We evaluated the effects of CUMS, fluoxetine, and CUMS re-exposure on tau and phospho-tau. Our results showed that a single exposure to CUMS caused a significant reduction in sucrose preference, indicating a state of anhedonia. The change in behavior was accompanied by specific alterations in phospho-tau protein levels, but fluoxetine treatment reversed the CUMS-induced impairments. Moreover, changes in sucrose preference and phospho-tau were more pronounced in rats re-exposed to CUMS than in those subjected to a single exposure. Our results suggest that changes in tau phosphorylation may contribute to the link between depression and AD.

Oxidative stress and cellular immunity in patients with recurrent aphthous ulcers

Recurrent aphthous ulcer (RAU) is an inflammatory condition of the oral mucosa characterized by painful, well-circumscribed, single or multiple round or ovoid ulcerations. The exact etiologic factor(s) of these ulcerations are not yet understood. The objective of this study was to evaluate inflammatory processes and free radical metabolism of 25 patients with RAUs compared to 25 healthy controls. The levels of malondialdehyde (MDA) and glutathione (GSH) were determined by high-performance liquid chromatography. Tumor necrosis factor-alpha (TNF-α), interleukin-2 (IL-2), IL-10, and IL-12 were determined by ELISA. Nitric oxide (NO), myeloperoxidase (MPO), total antioxidant status (TAS), and total oxidant status (TOS) levels were measured spectroscopically in serum. The levels of MDA, GSH, TNF-α, IL-2, IL-12, MPO, and TOS, and oxidative stress index (OSI) were higher, and the levels of NO, IL-10, and TAS were lower in patients with RAU than in controls. Statistical analysis showed that GSH, TNF-α, IL-2, IL-10, and OSI differed significantly in patients with RAU compared to controls. These parameters have important roles in oxidant/antioxidant defense.

Therapeutic concentration of morphine reduces oxidative stress in glioma cell line

Morphine is a potent analgesic opioid used extensively for pain treatment. During the last decade, global consumption grew more than 4-fold. However, molecular mechanisms elicited by morphine are not totally understood. Thus, a growing literature indicates that there are additional actions to the analgesic effect. Previous studies about morphine and oxidative stress are controversial and used concentrations outside the range of clinical practice. Therefore, in this study, we hypothesized that a therapeutic concentration of morphine (1 μM) would show a protective effect in a traditional model of oxidative stress. We exposed the C6 glioma cell line to hydrogen peroxide (H2O2) and/or morphine for 24 h and evaluated cell viability, lipid peroxidation, and levels of sulfhydryl groups (an indicator of the redox state of the cell). Morphine did not prevent the decrease in cell viability provoked by H2O2 but partially prevented lipid peroxidation caused by 0.0025% H2O2 (a concentration allowing more than 90% cell viability). Interestingly, this opioid did not alter the increased levels of sulfhydryl groups produced by exposure to 0.0025% H2O2, opening the possibility that alternative molecular mechanisms (a direct scavenging activity or the inhibition of NAPDH oxidase) may explain the protective effect registered in the lipid peroxidation assay. Our results demonstrate, for the first time, that morphine in usual analgesic doses may contribute to minimizing oxidative stress in cells of glial origin. This study supports the importance of employing concentrations similar to those used in clinical practice for a better approximation between experimental models and the clinical setting.

Acute stress-induced antinociception is cGMP-dependent but heme oxygenase-independent

Endogenous carbon monoxide (CO), which is produced by the enzyme heme oxygenase (HO), participates as a neuromodulator in physiological processes such as thermoregulation and nociception by stimulating the formation of 3′,5′-cyclic guanosine monophosphate (cGMP). In particular, the acute physical restraint-induced fever of rats can be blocked by inhibiting the enzyme HO. A previous study reported that the HO-CO-cGMP pathway plays a key phasic antinociceptive role in modulating noninflammatory acute pain. Thus, this study evaluated the involvement of the HO-CO-cGMP pathway in antinociception induced by acute stress in male Wistar rats (250-300 g; n=8/group) using the analgesia index (AI) in the tail flick test. The results showed that antinociception induced by acute stress was not dependent on the HO-CO-cGMP pathway, as neither treatment with the HO inhibitor ZnDBPG nor heme-lysinate altered the AI. However, antinociception was dependent on cGMP activity because pretreatment with the guanylate cyclase inhibitor 1H-[1,2,4] oxadiazolo [4,3-a] quinoxaline-1-one (ODQ) blocked the increase in the AI induced by acute stress.

Yeast CUP1 protects HeLa cells against copper-induced stress

As an essential trace element, copper can be toxic in mammalian cells when present in excess. Metallothioneins (MTs) are small, cysteine-rich proteins that avidly bind copper and thus play an important role in detoxification. YeastCUP1 is a member of the MT gene family. The aim of this study was to determine whether yeast CUP1 could bind copper effectively and protect cells against copper stress. In this study,CUP1 expression was determined by quantitative real-time PCR, and copper content was detected by inductively coupled plasma mass spectrometry. Production of intracellular reactive oxygen species (ROS) was evaluated using the 2',7'-dichlorofluorescein-diacetate (DCFH-DA) assay. Cellular viability was detected using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, and the cell cycle distribution of CUP1 was analyzed by fluorescence-activated cell sorting. The data indicated that overexpression of yeast CUP1 in HeLa cells played a protective role against copper-induced stress, leading to increased cellular viability (P<0.05) and decreased ROS production (P<0.05). It was also observed that overexpression of yeast CUP1 reduced the percentage of G1 cells and increased the percentage of S cells, which suggested that it contributed to cell viability. We found that overexpression of yeast CUP1 protected HeLa cells against copper stress. These results offer useful data to elucidate the mechanism of the MT gene on copper metabolism in mammalian cells.

Concomitant stress potentiates the preference for, and consumption of, ethanol induced by chronic pre-exposure to ethanol

Ethanol abuse is linked to several acute and chronic injuries that can lead to health problems. Ethanol addiction is one of the most severe diseases linked to the abuse of this drug. Symptoms of ethanol addiction include compulsive substance intake and withdrawal syndrome. Stress exposure has an important role in addictive behavior for many drugs of abuse (including ethanol), but the consequences of stress and ethanol in the organism when these factors are concomitant results in a complex interaction. We investigated the effects of concomitant, chronic administration of ethanol and stress exposure on the withdrawal and consumption of, as well as the preference for, ethanol in mice. Male Swiss mice (30–35 g, 8-10 per group) were exposed to an ethanol liquid diet as the only source of food for 15 days. In the final 5 days, they were exposed to forced swimming stress. Twelve hours after removal of the ethanol liquid diet, animals were evaluated for ethanol withdrawal by measuring anxiety-related behaviors and locomotor activity. Twenty-four hours after evaluation of ethanol withdrawal, they were evaluated for voluntary consumption of ethanol in a “three-bottle choice” paradigm. Mice exposed to chronic consumption of ethanol had decreased locomotor activity during withdrawal. Contrary to our expectations, a concomitant forced swimming stress did not aggravate ethanol withdrawal. Nevertheless, simultaneous ethanol administration and stress exposure increased voluntary consumption of ethanol, mainly solutions containing high concentrations of ethanol. These results showed that stressful situations during ethanol intake may aggravate specific addiction-related behaviors.

Effect of (+)-dehydrofukinone on GABAA receptors and stress response in fish model

(+)-Dehydrofukinone (DHF) is a major component of the essential oil of Nectandra grandiflora (Lauraceae), and exerts a depressant effect on the central nervous system of fish. However, the neuronal mechanism underlying DHF action remains unknown. This study aimed to investigate the action of DHF on GABAA receptors using a silver catfish (Rhamdia quelen) model. Additionally, we investigated the effect of DHF exposure on stress-induced cortisol modulation. Chemical identification was performed using gas chromatography-mass spectrometry and purity was evaluated using gas chromatography with a flame ionization detector. To an aquarium, we applied between 2.5 and 50 mg/L DHF diluted in ethanol, in combination with 42.7 mg/L diazepam. DHF within the range of 10-20 mg/L acted collaboratively in combination with diazepam, but the sedative action of DHF was reversed by 3 mg/L flumazenil. Additionally, fish exposed for 24 h to 2.5-20 mg/L DHF showed no side effects and there was sustained sedation during the first 12 h of drug exposure with 10-20 mg/L DHF. DHF pretreatment did not increase plasma cortisol levels in fish subjected to a stress protocol. Moreover, the stress-induced cortisol peak was absent following pretreatment with 20 mg/L DHF. DHF proved to be a relatively safe sedative or anesthetic, which interacts with GABAergic and cortisol pathways in fish.

Chemical and biochemical characterization of soybean produced under drought stress

Brazil is the second soybean (Glycine max L. Merrill) producer and exporter in the world. In 2005, soybean cultivated in the southeastern region of the country suffered drought stress imposed by adverse high temperatures and low humidity during its reproductive stage. Little information is available regarding the effect of drought stress on the quality of grains. In this study chemical and biochemical characteristics of five soybean samples belonging to three different cultivars grown under drought stress were evaluated. The samples did not meet standards for marketing and contained high amounts of green seeds. Grains were analyzed for appearance, 100 seed weight, humidity, water activity, proteins, lipids, lipoxygenase 1 activity, peroxides, and pigment contents after harvest and after 20 months of storage at room temperature. Acidity was measured also after 30 months of storage. The values of water activity and humidity were 0.6-0.7 and 8.7-11.9%, respectively, and they did not change during storage time, but there was an increase in acidity, which alludes to lipase activity. The activity of lipoxygenase 1 was greatly affected. Immediately after harvest, the green pigments were represented mainly by pheophytin a, followed by pheophytin b, small quantities of chlorophyll b and chlorophyll a, and traces of other chlorophyll derivatives. After 20 months of storage almost all green pigments had disappeared. Drought stress probably enhanced membrane permeability, which led to a lower pH and promoted transformation of chlorophylls to pheophytins.

White tea (Camellia sinensis) extract reduces oxidative stress and triacylglycerols in obese mice

White tea is an unfermented tea made from young shoots of Camellia sinensis protected from sunlight to avoid polyphenol degradation. Although its levels of catechins are higher than those of green tea (derived from the same plant), there are no studies addressing the relationship between this tea and obesity associated with oxidative stress.The objective of this study was to evaluate the effect of white tea on obesity and its complications using a diet induced obesity model. Forty male C57BL/6 mice were fed a high-fat diet to induce obesity (Obese group) or the same diet supplemented with 0.5% white tea extract (Obese + WTE) for 8 weeks. Adipose tissue, serum lipid profile, and oxidative stress were studied. White tea supplementation was not able to reduce food intake, body weight, or visceral adiposity. Similarly, there were no changes in cholesterol rich lipoprotein profile between the groups. A reduction in blood triacylglycerols associated with increased cecal lipids was observed in the group fed the diet supplemented with white tea. White tea supplementation also reduced oxidative stress in liver and adipose tissue. In conclusion, white tea extract supplementation (0.5%) does not influence body weight or adiposity in obese mice. Its benefits are restricted to the reduction in oxidative stress associated with obesity and improvement of hypertriacylglycerolemia.

Effect of different stress conditions on the stability of quercetin-loaded lipid microparticles produced with babacu ( Orbignya speciosa ) oil: evaluation of their potential use in food applications

Lipid micro and nanoparticles have been extensively investigated as carriers for hydrophobic bioactives in food systems because they can simultaneously increase the dispersibility of these lipophilic substances and help improve their bioavailability. In this study, lipid microparticles of babacu oil and denatured whey protein isolate were produced, and their ability to protect quercetin against degradation was evaluated over 30 days of storage. Additionally, the lipid microparticles were subjected to the typical stress conditions of food processing (presence of sucrose, salt, and thermal stresses), and their physico-chemical stability was monitored. The data show that the babacu microparticles efficiently avoided the oxidation of quercetin because 85% of the initial amount of the flavonoid was preserved after 30 days. The particles were notably stable up to a temperature of 70 °C for 10 minutes at relatively high concentrations of salt and sucrose. The type of stirring (mechanical or magnetic) also strongly affected the stability of the dispersions.

Physiological response of cowpea seeds to salinity stress

This work aimed to evoluate physiological response of cowpea (Vigna unguiculata L. Walp) seeds submitted to salt stress. Seeds of cultivars 'Epace-10'; 'Canapu' and 'Pitiúba' of cowpea, were submitted to germination test in germinator at 25(0)C, in "germitest" papers imbibed in distilled water or in 0, 10, 50, 100 and 200mol m-3 NaCl solutions. At the first and second counting of the germination test, normal seedlings were accounted, weighted and dried, obtaining data for vigor, total germination, fresh matter weight and dry matter weight. The seedlings hypocotyls, root and total length were measured total proteins content in cotyledons were obtained from germinating seeds. The presence of salt at concentrations higher than 50mol m-3 NaCl affect the germination, seedlings growth and cotyledons total protein synthesis of all cowpea cultivars. The seeds of cultivar pitiúba were is more tolerant to salinity, than the cultivars Canapu and Epace-10.

Physiological quality of wheat seeds submitted to saline stress

The objective of this experiment was to determine the influence of different salt levels (zero, 15, 30, 45 and 60mM NaCl) on seed physiological quality of two wheat cultivars (BRS 177 and BRS 179). SUMMARIZE METHODOLOGY. The results allow the following conclusions: the physiological quality (germination and vigor) of wheat seeds, cultivars BRS 179 and BRS 177, decrease with the increase of the salinity. The wheat seeds cv. BRS 179 performs better than BRS 177, mainly in higher salt concentrations (³ 45mM of NaCl). The electric conductivity of wheat seeds increases in function of the increment of the saline concentrations.