Carnosine prevents the activation of free-radical lipid oxidation during stress

Carnosine (beta-alanyl-L-histidine) injected to intact albino rats (20 mg/kg body weight) induces depletion of lipid peroxidation (LPO) products in brain and blood serum, an increase of superoxide scavenging activity in brain and serum, decrease of cholesterol: phospholipid ratio and increase of easy oxidizable phospholipid portion in brain lipid extracts. After painful stress (footshock during 2 hours) LPO products are accumulated in brain and serum, cholesterol: phospholipid ratio increases and the portion of easy oxidizable phospholipids decreases. Carnosine given before stress prevents LPO activation. Effects of carnosine and stress are not additive: LPO inhibition induced by carnosine is much more in rats subjected to stress.     

Chronic valproate treatment decreases the in vivo turnover of arachidonic acid in brain phospholipids: a possible common effect of mood stabilizers

Both (Li(+)) and valproic acid (VPA) are effective in treating bipolar disorder, but the pathway by which either works, and whether it is common to both drugs, is not agreed upon. We recently reported, using an in vivo fatty acid model, that Li(+) reduces the turnover rate of the second messenger arachidonic acid (AA) by 80% in brain phospholipids of the awake rat, without changing turnover rates of docosahexaenoic or palmitic acid. Reduced AA turnover was accompanied by down-regulation of gene expression and protein levels of an AA-specific cytosolic phospholipase A(2) (cPLA(2)). To see if VPA had the same effect on AA turnover, we used our in vivo fatty acid model in rats chronically administered VPA (200 mg/kg, i.p. for 30 days). Like Li(+), VPA treatment significantly decreased AA turnover within brain phospholipids (by 28-33%), although it had no effect on cPLA(2) protein levels. Thus, both mood stabilizers, Li(+) and VPA have a common action in reducing AA turnover in brain phospholipids, albeit by different mechanisms.     

The effect of carnosine on indicators of free radical lipid oxidation during acute stress in rats

The effect of carnosine intraperitoneal injection in rats (in doses 0.2, 2.0 or 20 mg/kg) on the vegetative parameters (arterial blood pressure, Hildebrandt index), the content of free radical oxidation (FRO) products and superoxide dismutase activity in serum and brain homogenates and brain lipid composition under normal condition and after different stress forms have been investigated. The carnosine injection in dose 20 mg/kg preserves and increase in arterial pressure and Hildebrandt index at all steps of stress development. The phase non-unidirectional changes in studied biochemical parameters have been revealed depending on the level of stress development in animals under control. The unidirectional and dose-dependent changes of phospholipid content and the level of brain lipids, decrease of FRO products in tissue and brain cholesterol, the increase of the superoxide dismutase activity of serum and brain homogenates have been found in intact and stressed animals after carnosine injection. A comparison of carnosine pharmacokinetics with concentration dependences of the antioxidative effect under in vitro and in vivo experiments comes to conclusion concerning the carnosine indirect adaptogenic action.     

Dose- and duration-dependent alterations by tellurium on lipid levels: differential effects in cerebrum,cerebellum, and brain stem of mice

The effect of various doses of sodium tellurite (1/50 LD50=0.4 mg/kg, 1/25 LD50=0.8 mg/kg, and 1/10 LD50=2.0 mg/kg body weight orally) on the lipid levels (cholesterol, triglycerides, phospholipids, esterified fatty acids, gangliosides, and total lipids) in the cerebrum, cerebellum, and brainstem of male albino mice was studied after 7 and 15 d of treatment. Sodium tellurite (2.0 mg/kg body weight) for 7 d has an apparent effect on the depletion of cholesterol, triglycerides, phospholipids, esterified fatty acids, and total lipids. The cholesterol content was decreased significantly in the cerebrum, cerebellum, and brainstem after 7 d of treatment with a 2.0-mg/kg dose compared to the control. On the other hand, treatment for 15 d with doses of 0.4, 0.8, and 2.0 mg/kg body weight resulted in a significant and dose-dependent increment in cholesterol level in the cerebrum, cerebellum, and brainstem. The triglycerides content was decreased significantly in the cerebrum, cerebellum, and brainstem with the 2.0-mg/kg dose after 7 d of treatment. The doses of 0.4, 0.8, and 2.0 mg/kg orally for 15 d resulted in a significant and dose-dependent depletion of triglycerides in the cerebrum, cerebellum, and brainstem. All the doses of tellurium (0.4, 0.8, and 2.0 mg/kg) both for 7 and 15 d have depleted the level of phospholipids in varying degrees of significance in the cerebrum, cerebellum, and brainstem. However, the level of esterified fatty acids was decreased significantly with the 2.0-mg/kg dose of tellurium for 7 d but increased with the 0.4-mg/kg dose for 15 d in the cerebrum and cerebellum. The level of gangliosides was depleted in the cerebrum but elevated in the cerebellum and brainstem after receiving a 2.0-mg/kg dose of sodium tellurite for 7 d. The content of gangliosides was increased with doses of 0.4 and 0.8 mg/kg but decreased with 2.0 mg/kg for 15 d in the cerebrum, cerebellum, and brainstem. The total lipids content was depleted significantly and dose dependently after 7 and 15 d of treatment in the cerebrum, cerebellum, and brainstem. These results suggest that sodium tellurite affects the lipids content differentially in various parts of the mice brain.     

Molecular mechanisms of the membrane-protective effect of litonit in chronic stress

It is confirmed that prophylactic use of Pyracetam (500 mg/kg), Pikamilon (10 mg/kg) and new product of GABA B-44 (30 mg/kg) for 10-days in the conditions of chronic stress normalizes the activity of the key enzymes of antiradical defence and the content of lipid peroxides, warns the decrement of phospholipids and the changes in its qualitative ratio, prevents multidirectional changes in the activity of ferments-markers in the membrane of the brain and erythrocytes. It is concluded that nootropic agents give membrane stabilizing effects.     

The influence of simvastatin, atorvastatin and high-cholesterol diet on acetylcholinesterase activity, amyloid beta and cholesterol synthesis in rat brain

OBJECTIVE: There is evidence to suppose that cholesterol-lowering medicine might confer protection against dementia, probably via modulation of cholesterol synthesis in the brain. The aim of the present study was to investigate the potential influence of statins and cholesterol diet on selected parameters relevant to Alzheimer's disease pathophysiology. METHODS: For 15 days, rats were orally administered simvastatin (10 or 20mg/kg b.wt.), atorvastatin (10 or 20mg/kg b.wt.), or aqua (control group); and one group was fed high-cholesterol (2%) diet. At the end of experiments brain (and plasma) cholesterol, lathosterol, hydroxymethylglutaryl-coenzyme A reductase protein, acetylcholinesterase activity, amyloid beta (40 and 42) and cholesterol synthesis rate (using the incorporation of deuterium from deuterated water) were determined and statistically compared to those of aqua. RESULTS: Both statins were able to lower cholesterol in the plasma, but none elicited an effect on total brain cholesterol. Significant reductions of brain lathosterol and cholesterol synthesis rate were observed after simvastatin and atorvastatin treatment. Acetylcholinesterase activity, amyloid beta and hydroxymethylglutaryl-coenzyme A reductase levels remained unaffected by the two drugs. CONCLUSIONS: This study brings additional evidence of a role for statins in cholesterol synthesis in the brain. Our data question the relationship between amyloid beta, acetylcholinesterase activity and cholesterol synthesis in the rat brain as well as the assumption about no exchange between peripheral and brain cholesterol pools.     

2,4,5-trimethoxycinnamic acid: the major metabolite of alpha-asarone, retains most of the pharmacological properties of alpha-asarone

2,4,5-trimethoxycinnamic acid (TMC), the major and non toxic metabolite of alpha-asarone (2,4,5-trimethoxy-1-propenyl benzene), retains most of the pharmacological properties of alpha-asarone, since both substances, administered to hypercholesterolemic rats at 80 mg/kg body wt, decreased total serum cholesterol, lowered LDL-cholesterol levels and kept unaffected HDL-cholesterol levels. In addition, both substances increased bile flow, especially in hypercholesterolemic rats, by rising the secretion of bile salts, phospholipids and bile cholesterol. These drugs also reduced cholesterol levels of gallbladder bile, whereas phospholipids and bile salts concentrations were increased, decreasing the cholesterol saturation index (CSI). We also found that alpha-asarone was 20 times better inhibitor of HMG-CoA reductase than TMC. This effect on HMG-CoA reductase was the only property highly reduced in TMC in comparison with alpha-asarone, while the other pharmacological properties of alpha-asarone were retained by TMC. These experiments strongly suggest that TMC can be further studied as a possible hypocholesterolemic and cholelitholytic agent.     

Acute Administration of Diazepam Provokes Redox Homeostasis Imbalance in the Rat Brain: Prevention by Simvastatin

We investigated the effects of acute diazepam (DZP) administration on thiobarbituric acid‐reactive substance (TBARS) levels, protein carbonyl content, and on the activities of the antioxidant enzymes catalase, glutathione peroxidase, and superoxide dismutase in the brain of rats. Additionally, we investigated the antioxidant role of chronic pretreatment with simvastatin on the effects provoked by DZP. Simvastatin was administered (1 or 10 mg/kg by oral gavage) for 30 days. On the 30th day of treatment, groups were randomized and DZP was administered (0.5 or 1.0 mg/kg by intraperitoneal injection). Control groups received saline. Results showed that DZP enhanced TBARS levels and protein carbonyl content and altered enzymatic activity in the brain of rats. Simvastatin prevented most of the alterations caused by DZP on the oxidative stress parameters. Data indicate that DZP administration causes an oxidative imbalance in the brain areas studied; however, in the presence of simvastatin, some of these alterations in oxidative stress were prevented.     

Circadian Rhythm of the Liver of Male Rats Pre-Treated with Phenobarbital—ii. Hexobarbital Sleeping Time and Lipids Content in Liver and Serum

The circadian rhythm of hexobarbital sleeping time and lipids content in liver and serum were studied in 226 male Sprague-Dawley rats pretreated daily at 0800-0900 with 70 mg/kg (study 1 or 3) or 50 mg/kg (study 2) phenobarbital (PB) orally for 7 days. Thereafter, eight (study 1) or five (study 2 and 3) rats each were studied at 4-hr intervals at 1000, 1400, 1800, 2200, 0200, 0600 and 1000 through the following day. The lighting schedule in the colony was 12:12 ± light:dark (light from 0600 to 1800). The hexobarbital sleeping times of PB-pretreated rats were generally shortened compared to the controls and no circadian rhythm was observed. PB-treatment increased slightly the liver content of cholesterol, and significantly that of triglycerides and phospholipids. Liver cholesterol and phospholipids showed circadian rhythms with peaks during the dark phase. No circadian rhythm of liver triglycerides existed. In serum, levels of triglycerides and phospholipids were slightly lowered by PB-treatment, while levels of cholesterol and beta-lipoprotein were not influenced. Serum values did not exhibit circadian rhythms.     

Effect of selenium on lipids, lipid peroxidation, and sulfhydryl group in neuroendocrine centers of rats

The effects of various doses of sodium selenite (0.05, 0.1, and 0.2 mg/kg body weight, ip) were studied on the content of phospholipids, cholesterol, esterified fatty acids (EFA), gangliosides, thiobarbituric acid reactive substance (TBARS), and sulfhydryl group in neuroendocrine centers of male Wistar rats for 7 d. The lowest dose of Se (0.05 mg/kg) did not alter the above parameters significantly in neuroendocrine centers. The content of phospholipids was depleted significantly in the pituitary and depletion in the pineal was 80.22% with a 0.1-mg/kg dose of Se, but this dose elevated its level significantly in the hypothalamus. Conversely, a 0.2-mg/kg dose of selenium elevated the level of phospholipids significantly in the pituitary and hypothalamus, the elevation in the pineal was 70%. Selenium, 0.1 mg/kg, elevated the level of cholesterol in the pituitary but depleted its level in the pineal (56.8%) and hypothalamus (13.60%). Selenium, 0.2 mg/kg, elevated the level of cholesterol significantly in the hypothalamus but its level was not significant in the pituitary and pineal. The depletion of esterified fatty acid in the pituitary and pineal with doses of 0.1 and 0.2 mg/kg was significant in the pituitary, whereas its depletion in the pineal was 85.4% and 69.26%, respectively. Selenium, 0.1 and 0.2 mg/kg, depleted the level of gangliosides significantly and dose dependently in the pituitary but has elevated its level significantly and dose dependently in the hypothalamus. Its depletion in the pineal was 87.1% and 67.8% with the 0.1- and 0.2-mg/kg dose of selenium, respectively. Selenium, 0.1 mg/kg, increased the content of TBARS significantly in neuroendocrine centers and its elevation in the pineal was 703.8%. Selenium, 0.2 mg/kg, elevated its level in the pituitary and it was 126.9% in the pineal, but this dose depleted its level significantly in the hypothalamus. The content of the sulfhydryl group with a 0.1-mg/kg dose of selenite was depleted significantly in neuroendocrine centers and it was 55.9% in the pineal. Selenium, 0.2 mg/kg, depleted the level of the sulfhydryl group more significantly in the pituitary and pineal, but its elevation in hypothalamus was significant.     

Characteristics of changes in lipids of granulation fibrous tissue of rats subjected to different doses and modes of melatonin administration

Melatonin influences the time-course of changes of lipids in granulation fibrous tissue in rats. Its effect depends on a dose, modes of administration (intraperitonial, subcutaneous or local) and duration of treatment. Intraperitonial administration of a single dose of melatonin (4 mg/kg) did not influence lipid content in the granulation fibrous tissue, while repeated injections of this hormone limited the increase in contents of lipids and phospholipids on the 5th and 8th days of regeneration. Long-term subcutaneous injections of melatonin caused distinct changes of lipids: at the dose of 0.3 mg/kg it prevented, and at the dose of 4 mg/kg it promoted the increase of lipid content in the granulation fibrous tissue on the fifth day of this study. Local application of melatonin solution (1.5 mg/ml) in early periods of regeneration caused insignificant changes of total lipids and total phospholipids in the granulation fibrous tissue. However, the higher concentration (15 mg/ml) of melatonin caused the decrease of total lipids due to reduced content of cholesterol and triglycerides and the increase of total phospholipids and some of their fractions.     

Selenium altered the levels of lipids, lipid peroxidation, and sulfhydryl groups in straitum and thalamus of rat

The effect of sodium selenite (0.05, 0.1, and 0.2 mg/kg body weight, ip) on the lipid levels (total lipids, phospholipids, cholesterol, gangliosides), thiobarbituric acid reactive substance (TBARS), and sulfhydryl group (-SH) in the straitum and thalamus of a male Wistar rat was studied after 7 d of treatment. The level of total lipids and cholesterol was significantly and dose-dependently elevated in the straitum and thalamus with 0.1 and 0.2 mg/kg of sodium selenite. However, the cholesterol level was significantly increased only with 0.2 mg/kg of sodium selenite in the thalamus. The level of phospholipids and gangliosides was more significant with 0.1 mg/kg of sodium selenite as compared to 0.2 mg. No significant alteration on the gangliosides level was observed in the thalamus with various doses of sodium selenite although the elevation with 0.2 mg dose was 25.9%. The content of TBARS was elevated dose dependently in straitum, but its level was depleted significantly with 0.1-mg/kg dose of sodium selenite in the thalamus. The level of the -SH group was significantly depleted in the straitum with 0.1-mg/kg dose of sodium selenite; conversely, this dose has significantly elevated the levels of-SH group in the thalamus.     

The effects of adrenaline, reserpine, and atropine on acetylcholine content of the brain and peripheral ganglia in stress.

The effects of adrenaline, reserpine and atropine on ACh content in the cerebral cortex and brain stem and in the gastric tissues were investigated in the rats at rest and during stress induced by forced swimming. Adrenaline administered intraperitoneally twice at an interval of two hours in doses of 0.1 mg/kg and then subcutaneously in a dose 0.5 mg/kg increased acetylcholine content in the cerebral cortex of resting and in the gastric tissues of resting and swimming rats. Reserpine in doses of 3 mg/kg given 48, 24 and 7 hours before the experiment caused a significant rise in ACh content in the cerebral cortex of resting rats and in the brain stem during stress. Atropine given in a dose of 6 mg/kg at 8 h intervals during 2 days caused a significant fall in ACh level in the cerebral cortex and brain stem of resting rats, in the cortex of swimming animals, as well as a considerable rise in the gastric tissues of swimming rats.     

Chronic N-methyl-D-aspartate administration increases the turnover of arachidonic acid within brain phospholipids of the unanesthetized rat

Whereas antibipolar drug administration to rats reduces brain arachidonic acid turnover, excessive N-methyl-d-aspartate (NMDA) signaling is thought to contribute to bipolar disorder symptoms and may increase arachidonic acid turnover in rat brain phospholipids. To determine whether chronic NMDA would increase brain arachidonic acid turnover, rats were daily administered NMDA (25 mg/kg, ip) or vehicle for 21 days. In unanesthetized rats, on day 21, [1-(14)C]arachidonic acid was infused intravenously and arterial blood plasma was sampled until the animal was euthanized at 5 min and its microwaved brain was subjected to chemical and radiotracer analysis. Using equations from our in vivo fatty acid model, we found that compared with controls, chronic NMDA increased the net rate of incorporation of plasma unesterified arachidonic acid into brain phospholipids (25-34%) as well as the turnover of arachidonic acid within brain phospholipids (35-58%). These changes were absent at 3 h after a single NMDA injection. The changes, opposite to those after chronic administration of antimanic drugs to rats, suggest that excessive NMDA signaling via arachidonic acid may be a model of upregulated arachidonic acid turnover in brain phospholipids.     

Clofibrate-induced changes in the liver, heart, brain and white adipose lipid metabolome of Swiss-Webster mice

Peroxisome proliferator activated receptor alpha (PPARα) agonists are anti-hyperlipidemic drugs that influence fatty acid combustion, phospholipid biosynthesis and lipoprotein metabolism. To evaluate impacts on other aspects of lipid metabolism, we applied targeted metabolomics to liver, heart, brain and white adipose tissue samples from male Swiss-Webster mice exposed to a 5 day, 500 mg/kg/day regimen of i.p. clofibrate. Tissue concentrations of free fatty acids and the fatty acid content of sphingomyelin, cardiolipin, cholesterol esters, triglycerides and phospholipids were quantified. Responses were tissue-specific, with changes observed in the liver > heart >> brain > adipose. These results indicate that liver saturated fatty acid-rich triglycerides feeds clofibrate-induced monounsaturated fatty acid (MUFA) synthesis, which were incorporated into hepatic phospholipids and sphingomyelin. In addition, selective enrichment of docosahexeneoic acid in the phosphatidylserine of liver (1.7-fold), heart (1.6-fold) and brain (1.5-fold) suggests a clofibrate-dependent systemic activation of phosphatidylserine synthetase 2. Furthermore, the observed ∼20% decline in cardiac sphingomyelin is consistent with activation of a sphingomeylinase with a substrate preference for polyunsaturate-containing sphingomyelin. Finally, perturbations in the liver, brain, and adipose cholesterol esters were observed, with clofibrate exposure elevating brain cholesterol arachidonyl-esters ∼20-fold. Thus, while supporting previous findings, this study has identified novel impacts of PPARα agonist exposure on lipid metabolism that should be further explored. Electronic Supplementary Material The online version of this article (doi:) contains supplementary material, which is available to authorized users. Supplementary data include an excel file with quantitative values (nmol/g tissue) of all lipids measured in this study (Table S1–5) as well as a table with the scientific name, molecular name and common name of all fatty acids reported (Table S5).     

Postprandial LDL phenolic content and LDL oxidation are modulated by olive oil phenolic compounds in humans

Olive oil phenolic compounds are potent antioxidants in vitro, but evidence for antioxidant action in vivo is controversial. We examined the role of the phenolic compounds from olive oil on postprandial oxidative stress and LDL antioxidant content. Oral fat loads of 40 mL of similar olive oils, but with high (366 mg/kg), moderate (164 mg/kg), and low (2.7 mg/kg) phenolic content, were administered to 12 healthy male volunteers in a cross-over study design after a washout period in which a strict antioxidant diet was followed. Tyrosol and hydroxytyrosol, phenolic compounds of olive oil, were dose-dependently absorbed (p<0.001). Total phenolic compounds in LDL increased at postprandial state in a direct relationship with the phenolic compounds content of the olive oil ingested (p<0.05). Plasma concentrations of tyrosol, hydroxytyrosol, and 3-O-methyl-hydroxytyrosol directly correlated with changes in the total phenolic compounds content of the LDL after the high phenolic compounds content olive oil ingestion. A 40 mL dose of olive oil promoted a postprandial oxidative stress, the degree of LDL oxidation being lower as the phenolic content of the olive oil administered increases. In conclusion, olive oil phenolic content seems to modulate the LDL phenolic content and the postprandial oxidative stress promoted by 40 mL olive oil ingestion in humans.     

Antistress effects of vitamin E and dimethylsulfoxide during their combined administration in low doses

Low doses of vitamin E (5 mg/kg body weight) and dimethyl sulfoxide (50 mg/kg) given simultaneously orally to albino rats prevented the disturbances of the behaviour and vegetative functions induced by chronic emotional painful stress. The adaptive effect of vitamin E or dimethyl sulfoxide given alone was much lower or altogether absent. The antioxidant combination used decreased the intensity of lipid peroxidation in the brain and blood serum as well as cholesterol content in brain lipids and activated brain superoxide dismutase and nonenzymatic superoxide scavenging activity of the serum. The results obtained suggest that the combination of vitamin E with dimethyl sulfoxide may be used for the treatment of pathological conditions accompanied by lipid peroxidation syndrome.     

Role of beta-carotene in ameliorating the cadmium-induced oxidative stress in rat brain and testis

The role of oxidative stress in chronic cadmium (Cd) toxicity and its prevention by cotreatment with beta-carotene was investigated. Adult male rats were intragastrically administered 2 mg CdCl2/kg body weight three times a week intragastrically for 3 and 6 weeks. Brain and testicular thiobarbituric acid reactive substances (TBARS) was elevated after 3 and 6 weeks of Cd administration, indicating increased lipid peroxidation (LPO) and oxidative stress. Cellular damage was indicated by inhibition of adenosine triphosphatase (ATPase) activity and increased lactate dehydrogenase (LDH) activity in brain and testicular tissues. Chronic Cd administration resulted in a decline in glutathione (GSH) content and a decrease of superoxide dismutase (SOD) and glutathione S-transferase (GST) activity in both organs. Administration of beta-carotene (250 IU/kg i.g.) concurrent with Cd ameliorated Cd-induced LPO. The brain and testicular antioxidants, SOD, GST, and GSH, decreased by Cd alone, were restored by beta-carotene cotreatment. Concurrent treatment with beta-carotene also ameliorated the decrease in ATPase activity and the increase in LDH activity in brain and testis of Cd-treated rats, indicating a prophylactic action of beta-carotene on Cd toxicity. Therefore, the results indicate that the nutritional antioxidant beta-carotene ameliorated oxidative stress and the loss of cellular antioxidants and suggest that beta-carotene may control Cd-induced brain and testicular toxicity.     

Tissue-selective inhibition of cholesterol synthesis in vivo by pravastatin sodium, a 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitor

Tissue selectivity of pravastatin sodium (pravastatin) in inhibition of cholesterol synthesis was investigated and its effect was compared with other 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, such as lovastatin, simvastatin and ML-236B. Inhibition of cholesterol synthesis in vivo was measured by incorporation of radioactivity into the sterol fraction 1 h after intraperitoneal injection of [14C]acetate to mice. The drugs were orally administered to mice 2 h before the acetate injection. When pravastatin at a dose of 20 mg/kg was administered to mice, about 90% inhibition of cholesterol synthesis was observed in liver and ileum, but the inhibition was less than 14% in kidney, spleen, adrenal, testis, prostate and brain. This tissue selectivity of pravastatin was also demonstrated even in varying doses (5-100 mg/kg) and time (75-180 min) after drug administration. Other 3-hydroxyl-3-methylglutaryl coenzyme A reductase inhibitors did not show such a tissue-selective inhibition of sterol synthesis under the same conditions. These results obtained with the in vivo study were confirmed in vitro by the inhibition of sterol synthesis in various cultured cells and rats lenses, as well as by cellular uptake of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors.