Evaluation of oxidant-antioxidant status in oral toxicity of fish oil methyl esters and diesel fuel in male rats.

This study was conducted to compare the effects of oral toxicity induced by fish oil biodiesel and diesel fuel. Diesel and fish oil biodiesel were administered by oral gavage to rats. For this purpose, 35 rats were divided into five groups. Sunflower oil of 250 mg kg(-1) was administered to the rats in the control group by oral gavage. The rats in the D250 and D500 groups were administered by oral gavage 250 mg kg(-1) and 500 mg kg(-1) of diesel fuel dissolved in equal amounts of sunflower oil, respectively. The rats in the F250 and F500 groups were administered by oral gavage 250 mg kg(-1) and 500 mg kg(-1) of fish oil biodiesel dissolved in equal amounts of sunflower oil, respectively. At the end of the study, malondialdehyde (MDA) and reduced glutathione (GSH) levels were measured in the whole blood; catalase (CAT) activity level was measured in erythrocytes; and nitrite (NO2) and nitrate (NO3) levels were measured in the serum. It was observed that the whole blood MDA levels of the diesel groups were considerably different from those in the control and fish oil biodiesel groups (p < 0.001). GSH levels in the control group were observed to be considerably different from those in all other groups (p < 0.001). Serum NO3 concentrations in the diesel groups were found to be considerably different from those in the control and biodiesel groups. Serum NO2 concentrations in one of the diesel groups were significantly different from those in the control and biodiesel groups (p < 0.01 and p < 0.05, respectively). The CAT activity of the control group was observed to be different from that in the other groups. According to these results, both fish oil biodiesel and diesel fuel are thought to cause lipid peroxidation. It was observed that fish oil biodiesel does not induce as much oxidative damage as does the diesel fuel. It is suggested that fish oil biodiesel should be preferred as an alternative to the diesel.

Pre-emptive anti-hyperalgesic effect of electroacupuncture in carrageenan-induced inflammation: role of nitric oxide.

Central sensitization theory has been defined as pivotal for understanding the excitability changes in central neurons following peripheral inflammation or neuropathic injury. Considerable evidence has demonstrated that activation of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors and subsequent nitric oxide (NO) production are the key in these changes. Consequently, neuromodulator drugs have been developed during the last decades. The electroacupuncture (EA) that acts as biochemical modulator in the spinal horn cord would prevent these changes. The aim of this study was to determine the thermal anti-hyperalgesic effect of EA (10 Hz, 3 mA) and its combination with L-NAME as nitric oxide synthase (NOS) inhibitor in carrageenan-induced hyperalgesia in rats. Also, it investigated the changes in the plasmatic concentrations of NO metabolites. Moreover, the EA combination with sub-effective dose of ketamine as a NMDA antagonist was tested. The EA pre-treatment conducted in unsedated, unrestrained and conscious animals showed a thermal anti-hyperalgesic effect in correspondence with plasmatic increase of NO metabolites. The L-NAME (30 mg/kg) pre-administration decreased significantly the plasmatic concentrations of NO(2)(-)/NO(3)(-) and suppressed the anti-hyperalgesic effect of EA. The combination of EA with ketamine enhanced the anti-hyperalgesic effect. These data constitute the first report that suggested the participation, at least in part, of the L-arginine-NOS-NO-GMPc pathway activation in anti-hyperalgesic effect of EA in carrageenan-induced inflammation model.

Dietary supplementation with laminarin, a fermentable marine beta (1-3) glucan, protects against hepatotoxicity induced by LPS in rat by modulating immune response in the hepatic tissue.

We tested the hypothesis that laminarin (LAM), a beta (1-3) polysaccharide extracted from brown algae, can modulate the response to a systemic inflammation. Male Wistar rats (n=7 per group) were fed a standard diet (control) or a diet supplemented with LAM for 25 days (5% during 4 days followed by 10% during 21 days). Thereafter, Escherichia coli lipopolysaccharides (LPS; 10 mg/kg i.p.) were injected and the animals were sacrificed 24 h after LPS challenge. The hypothermia, hyperglycemia and hypertriglyceridemia occurring early after LPS administration were less pronounced in LAM-treated rats than in controls. The increase in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) activities - reflecting hepatic alterations - was lessened after LPS injection in LAM-treated rats compared to control rats. LAM treatment decreased serum monocytes number, nitrite (NO2) and tumor necrosis factor-alpha (TNF-alpha). LAM also modulated intra-hepatic immune cells: it lowered the occurrence of peroxidase-positive cells (corresponding to monocytes/neutrophils) and, in contrast, it increased the number of ED2-positive cells, corresponding to resident hepatic macrophages, i.e. Kupffer cells. In conclusion, the hepatoprotective effect of marine beta (1-3) glucan during endotoxic shock may be linked to its immunomodulatory properties. We propose that both lower recruitment of inflammatory cells inside the liver tissue and lower secretion of inflammatory mediators play a role in the tissue protective effect of LAM. These effects could be due to a direct effect of beta-glucan on immune cells, or to an indirect effect through their dietary fibre properties (fermentation in the gut).

Interaction of nitrogen dioxide with human plasma. Antioxidant depletion and oxidative damage.

Nitrogen dioxide (NO2.) is often present in inhaled air and may be generated in vivo from nitric oxide. Exposure of human blood plasma to NO2. caused rapid losses of ascorbic acid, uric acid and protein thiol groups, as well as lipid peroxidation and depletions of alpha-tocopherol, bilirubin and ubiquinol-10. No increase in protein carbonyls was detected. Supplementation of plasma with ascorbate decreased the rates of lipid peroxidation, alpha-tocopherol depletion and loss of uric acid. Uric acid supplementation decreased rates of lipid peroxidation but not the loss of alpha-tocopherol. We conclude that ascorbic acid, protein -SH groups, uric acid and alpha-tocopherol may be important agents protecting against NO2. in vivo. If these antioxidants are depleted, peroxidation of lipids occurs and might contribute to the toxicity of NO2..