Rafael de Lima Portella

Protective action of ethanolic extract of Rosmarinus officinalis L. in gastric ulcer prevention induced by ethanol in rats.

The pathology of a gastric ulcer is complex and multifactorial. Gastric ulcers affect many people around the world and its development is a result of the imbalance between aggressive and protective factors in the gastric mucosa. In this study, we evaluated the ethanolic extract of Rosmarinus officinalis L. (eeRo); this plant, more commonly known as rosemary, has attracted the interest of the scientific community due to its numerous pharmacological properties and their potential therapeutic applications. Here, we tested the preventive effects of eeRo against gastric ulcer induced by 70% ethanol in male Wistar rats. In addition, we aimed to clarify the mechanism involved in the preventive action of the eeRo in gastric ulcers. Based on the analysis of markers of oxidative damage and enzymatic antioxidant defense systems, the measurement of nitrite and nitrate levels and the assessment of the inflammatory response, the eeRo exhibited significant antioxidant, vasodilator and antiinflammatory properties.

Diphenyl diselenide, a simple glutathione peroxidase mimetic, inhibits human LDL oxidation in vitro.

Oxidative modification of low-density lipoprotein (LDL) represents an important factor in atherogenesis. In the present study, we have investigated the antioxidant capability of diphenyl diselenide (PhSe)(2), a simple organoseleno compound, against copper (Cu2+) and peroxyl radical-induced human LDL oxidation in vitro. In initial studies using human serum, (PhSe)(2) caused a dose-dependent inhibition of Cu(2+)-induced lipid peroxidation, which was correlated to thiol consumption. (PhSe)(2) increased lipid peroxidation lag phase and decreased lipid peroxidation rate in isolated human LDL, evaluated by measuring both conjugated diene (CD) and thiobarbituric acid reactive substances (TBARS) levels. Consistent with these observations, (PhSe)(2) showed a marked inhibitory effect on 2,2-azobis(2-amidinopropane dihydrochloride) (AAPH)-induced oxidation of LDL or parinaric acid (PnA) incorporated into LDL. (PhSe)(2) also displayed a dose-dependent protective effect against Cu(2+)-induced lipid peroxidation in rat aortic slices. Interestingly, besides the antioxidant effects of (PhSe)(2) toward the lipid moieties of LDL, which was related to its thiol-peroxidase activity, protein moieties from human isolated LDL were also protected against Cu(2+)-induced oxidation. The results presented herein are the first to show that (i) (PhSe)(2) inhibits lipid peroxidation in human isolated LDL in vitro, (ii) this phenomenon is related to its thiol-peroxidase activity, and (iii) this chalcogen also prevents the oxidation of protein moieties of human LDL. Taken together, such data render (PhSe)(2) a promising molecule for pharmacological studies with respect to the atherogenic process.

Diphenyl diselenide decreases serum levels of total cholesterol and tissue oxidative stress in cholesterol-fed rabbits.

Hypercholesterolaemia and oxidative stress are well-known risk factors in coronary artery diseases. Diphenyl diselenide is a synthetic organoselenium compound that has been shown to have in vitro and in vivo antioxidant properties. In this study, we investigated whether diphenyl diselenide could reduce the hypercholesterolaemia and diminish the tissue oxidative stress in cholesterol-fed rabbits. Twenty-four New Zealand white male rabbits were randomly divided into four groups. Each group was fed a different diet as follows: Control group--regular chow; Cholesterol group--1% cholesterol-enriched diet; diphenyl diselenide group--regular diet supplemented with 10 ppm diphenyl diselenide; and Chol/diphenyl diselenide group--the same cholesterol-rich supplemented with 10 ppm diphenyl diselenide. After 45 days of treatment, the rabbits were killed and the blood, liver, and brain were used for laboratory analysis. The results showed that the serum levels of total cholesterol were markedly increased in cholesterol-fed rabbits and the consumption of diphenyl diselenide decreased these levels approximately twofold in Chol/diphenyl diselenide rabbits (P < 0.05). The intake of diphenyl diselenide by hypercholesterolaemic rabbits diminished the serum and hepatic thiobarbituric acid reactive substances levels as well as the production of reactive oxygen species in the blood and brain (P < 0.05) when compared to the cholesterol group. In addition, diphenyl diselenide supplementation increased hepatic and cerebral delta-aminolevulinic dehydratase activity and hepatic non-protein thiol groups levels despite hypercholesterolaemia (P < 0.05). In summary, the results showed that diphenyl diselenide reduced the hypercholesterolaemia and the oxidative stress in cholesterol-fed rabbits.

Changes in biochemical parameters in rabbits blood after oral exposure to diphenyl diselenide for long periods

The concept that selenium-containing molecules may be better antioxidants than classical antioxidants, has led to the design of synthetic organoselenium compounds. The present study was conducted to evaluate the potential toxicity of long time oral exposure to diphenyl diselenide (PhSe)2 in rabbits. Male adult New Zealand rabbits were divided into four groups, group I served as control; groups II, III and IV received 0.3, 3.0 and 30 ppm of (PhSe)2 pulverized in the chow for 8 months. A number of parameters were examined in blood as indicators of toxicity, including delta-aminolevulinate dehydratase (delta-ALA-D), catalase, glutathione peroxidase (GPx), alanine aminotransferase (ALT), aspartate aminotransferase (AST), urea, creatinine, TBARS, non-protein-SH, ascorbic acid and selenium. The results demonstrated that 6 and 8 months of 30 ppm (PhSe)2 intake caused a significant increase in blood delta-ALA-D activity. Erythrocyte non-protein thiol levels were significantly increased after 2 months of 30 ppm (PhSe)2 intake and then return to control levels after prolonged periods of intake. Ingestion of 3.0 ppm of (PhSe)2 for 8 months significantly increased catalase activity in erythrocytes. Conversely, no alterations in GPx, ALT, AST, TBARS and selenium levels were observed in rabbit serum, conversely, selenium levels in peri-renal adipose tissue were significantly increased after 8 months of 30 ppm (PhSe)2 intake, indicating its great lipophylicity. The present results suggest that diphenyl diselenide was not hepato- or renotoxic for rabbits, but caused some biochemical alterations that can be related to some pro-oxidant activity of the compound (particularly the reduction in Vitamin C).

Oximes as inhibitors of low density lipoprotein oxidation.

AIMS Several lines of evidence support the hypothesis that the oxidation of low density lipoprotein (LDL) may play a crucial role in the initiation and progression of atherosclerosis. Various studies have shown a positive effect of antioxidant compounds on oxidative modification of LDL and atherogenesis. In view of this, we have investigated the possible antioxidant activity of two new oximes against Cu2+- induced LDL and serum oxidation. Oximes are used in organophosphate (OP) poisoning acting by restoring the cholinesterase function. However, their antioxidant capacities are not well understood and poorly studied. MAIN METHODS We measured, in a Cu2+-induced oxidation, the conjugated dienes formation in serum and LDL and the loss of tryptophan fluorescence as well as the TBARS formation in the LDL. KEY FINDINGS Our results showed that both oximes act as antioxidant and they are able to prevent LDL oxidation in a concentration-dependent manner. When human LDL or serum was oxidized by Cu2+, our oximes showed a significant increase in the lag phase of conjugated dienes and a significant decrease in the thiobarbituric acid reactive substances production. Moreover, oximes protected tryptophan residues of ApoB-100 in the early stage of LDL oxidation and during the subsequent propagation phase. SIGNIFICANCE These results indicated for the first time that oximes have a potential antioxidant activity and they could act in the prevention of LDL and serum oxidation. Thus, we speculated that our oximes could act as antiatherogenic compounds besides their well described role as antidote for organophosphate poisoning.

Diphenyl Diselenide Modulates Gene Expression of Antioxidant Enzymes in the Cerebral Cortex, Hippocampus and Striatum of Female Hypothyroid Rats

INTRODUCTION Cellular antioxidant signaling can be altered either by thyroid disturbances or by selenium status. AIMS To investigate whether or not dietary diphenyl diselenide can modify the expression of genes of antioxidant enzymes and endpoint markers of oxidative stress under hypothyroid conditions. METHODS Female rats were rendered hypothyroid by continuous exposure to methimazole (MTZ; 20 mg/100 ml in the drinking water) for 3 months. Concomitantly, MTZ-treated rats were either fed or not with a diet containing diphenyl diselenide (5 ppm). mRNA levels of antioxidant enzymes and antioxidant/oxidant status were determined in the cerebral cortex, hippocampus and striatum. RESULTS Hypothyroidism caused a marked upregulation in mRNA expression of catalase, superoxide dismutase (SOD-1, SOD-3), glutathione peroxidase (GPx-1, GPx-4) and thioredoxin reductase (TrxR-1) in brain structures. SOD-2 was increased in the cortex and striatum, while TrxR-2 increased in the cerebral cortex. The increase in mRNA expression of antioxidant enzymes was positively correlated with the Nrf-2 transcription in the cortex and hippocampus. Hypothyroidism caused oxidative stress, namely an increase in lipid peroxidation and reactive oxygen species levels in the hippocampus and striatum, and a decrease in nonprotein thiols in the cerebral cortex. Diphenyl diselenide was effective in reducing brain oxidative stress and normalizing most of the changes observed in gene expression of antioxidant enzymes. CONCLUSION The present work corroborates and extends that hypothyroidism disrupts antioxidant enzyme gene expression and causes oxidative stress in the brain. Furthermore, diphenyl diselenide may be considered a promising molecule to counteract these effects in a hypothyroidism state.Introduction: Cellular antioxidant signaling can be altered either by thyroid disturbances or by selenium status. Aims: To investigate whether or not dietary diphenyl diselenide can modify the expression of genes of antioxidant enzymes and endpoint markers of oxidative stress under hypothyroid conditions. Methods: Female rats were rendered hypothyroid by continuous exposure to methimazole (MTZ; 20 mg/100 ml in the drinking water) for 3 months. Concomitantly, MTZ-treated rats were either fed or not with a diet containing diphenyl diselenide (5 ppm). mRNA levels of antioxidant enzymes and antioxidant/oxidant status were determined in the cerebral cortex, hippocampus and striatum. Results: Hypothyroidism caused a marked upregulation in mRNA expression of catalase, superoxide dismutase (SOD-1, SOD-3), glutathione peroxidase (GPx-1, GPx-4) and thioredoxin reductase (TrxR-1) in brain structures. SOD-2 was increased in the cortex and striatum, while TrxR-2 increased in the cerebral cortex. The increase in mRNA expression of antioxidant enzymes was positively correlated with the Nrf-2 transcription in the cortex and hippocampus. Hypothyroidism caused oxidative stress, namely an increase in lipid peroxidation and reactive oxygen species levels in the hippocampus and striatum, and a decrease in nonprotein thiols in the cerebral cortex. Diphenyl diselenide was effective in reducing brain oxidative stress and normalizing most of the changes observed in gene expression of antioxidant enzymes. Conclusion: The present work corroborates and extends that hypothyroidism disrupts antioxidant enzyme gene expression and causes oxidative stress in the brain. Furthermore, diphenyl diselenide may be considered a promising molecule to counteract these effects in a hypothyroidism state.

Thiosemicarbazone derivate protects from AAPH and Cu2+ -induced LDL oxidation.

AIMS Several lines of evidence support the hypotheses that the oxidation of low density lipoprotein (LDL) may play a crucial role in the initiation and progression of atherosclerosis. Oxidative stress is one of the causes of the overproduction of reactive species that increase the formation of oxidized LDL. Thiosemicarbazones are compounds used in anticancer, antiviral and antifungal therapy; however, its redox activity has been controversial. Thus, we tested, in vitro, a possible antioxidant activity of a thiosemicarbazone derivate, the isatin-3-N(4)-benzilthiosemicarbazone (IBTC). MAIN METHODS We measured the conjugated diene formation in serum and LDL as well as the loss of tryptophan fluorescence in LDL induced by two oxidant agents, 2,2-azobis(2-amidinopropane dihydrochloride) (AAPH) and Cu(2+). Thiobarbituric acid reactive substances (TBARS) formation in LDL and in different rat tissues was also assessed. The toxicity of IBTC was measured using aortic slices viability assay. KEY FINDINGS Our results show that IBTC significantly reduced the AAPH and Cu(2+)-induced formation of conjugated dienes, increased in a dose-dependent manner the lag phase and the t(1/2) of tryptophan fluorescence, and reduced the TBARS formation in LDL, plasma and rat tissues, showing no toxicity to aortic slices. SIGNIFICANCE These results indicate that IBTC is a good antioxidant and a promising antiatherogenic agent for further studies in vivo.

Effect of repeated restraint stress and clomipramine on Na+/K+-ATPase activity and behavior in rats

Activation of the limbic‐hypothalamic‐pituitary‐adrenal axis (LHPA) and the release of glucocorticoids are fundamental for the adaptive response and immediate survival of an organism in reaction to acute stimuli. However, high levels of glucocorticoids in the brain may produce neuronal injury and a decrease of Na+/K+‐ATPase activity, with effects on neurotransmitter signaling, neural activity, as well as the whole animal behavior. Clomipramine is a tricyclic antidepressant that inhibits the reuptake of serotonin and norepinephrine by indirect actions on the dopaminergic system and LHPA axis. Its chronic use increases the bodys ability to cope with stress; however, high doses can potentiate its side effects on memory, learning, and sensory motor function. The purpose of the present study was to compare the effect of repeated restraint stress and clomipramine treatment on Na+/K+‐ATPase activity and on the behavior of male rats. Changes in the behavioral response were evaluated by measuring the memory, learning, anxiety, and exploratory responses. Our results showed that exposure to repeated restraint stress reduced levels of Na+/K+‐ATPase in brain structures and changed short and long‐term memory, learning, and exploratory response when compared to the control group. Exposure to clomipramine treatment increased anxiety levels and reduced Na+/K+‐ATPase activity in the cerebral cortex as well as short term memory, learning, and exploratory response. In conclusion, the present results provide additional evidence concerning how repeated restraint stress and clomipramine chronically administered at higher dose levels affect the neural activity and behavior of male rats.

Respostas bioquímicas e físicas ao treinamento realizado dentro e fora da água em atletas de futsal

Abstract: The aim of this study was analyzed the effects of physical training on land and in water (water exercise) on the biochemical levels related to the damage and physical capacity of soccer players. Twelve soccer players were divided into two groups: 1) group training on land (GTL, n=6) and 2) group training in water (GTW, n=6). Levels of aerobic and anaerobic capacities by RAST and Yo-yo intermittent tests, damage by creatine kinase (CK) and lactate dehydrogenase (LDH), oxidative stress levels by thiobarbituric acid reactive substances (TBARS) and catalase activity (CAT) were evaluated before and after 10 sessions of physical training (p<0,05). The results showed that both groups increased their aerobic capacity after ten training sessions. The GTW presented higher CAT at rest and lower levels of CK to be compared with the GTL at the 10 th training session. The conclusion is that training in water seems to be an interesting alternative to improve the physical capacities and to protect muscle during pre season training of indoor soccer players.

Multiple mechanistic action of Rosmarinus officinalis L. extract against ethanol effects in an acute model of intestinal damage

The high levels of oxidative stress and inflammation can be present in the etiology of degenerative intestinal pathologies associated with ethanol ingestion. The Rosmarinus officinalis L. has exhibited several physiological and medicinal activities. In this investigation, we intended to clarify, for the first time, the antioxidant and anti-inflammatory effects of ethanolic extract of Rosmarinus officinalis L. (eeRo) against an acute damage induced by ethanol, specifically in the small intestine of rats. The rats were treated three times, at every 24 h, with eeRo at 500-1000 mg/kg or vehicle, oral gavage. All groups got a single dose of ethanol (2 ml/kg), oral gavage, after 36 h of fasting and 1 h after the last dose of eeRo or vehicle administration. We performed the mensuration of oxidative stress profile in lipid peroxidation in serum and intestine; Na+/K+ ATPase, catalase, and superoxide dismutase activities assays only in intestine; and anti-inflammatory evidences of eeRo in myeloperoxidase activity assay only in the intestine. The eeRo was able to protect the animals against the lipid peroxidation in serum and intestine. It prevented the reduction in Na+/K+ ATPase and catalase levels induced by ethanol in the intestine. In addition, eeRo increased the superoxide dismutase activity when compared to control and protected the intestine against elevations in myeloperoxidase activity caused by ethanol. Our results suggested that eeRo exerted a significant intestinal protective effect by antioxidant and anti-inflammatory mechanisms. Thus, the eeRo represented a promising agent against intestinal lesions induced by ethanol.