Antioxidant effect of a novel class of telluroacetilene compounds: Studies in vitro and in vivo

AimsThe effect of telluroacetylenes a–d on pharmacological assays was investigated in vitro. A second objective of this study was to investigate the antioxidant action of compound b against the oxidative damage induced by sodium nitroprusside (SNP) in mouse brain.Main methodsIn in vitro experiments, lipid peroxidation (LP) and protein carbonyl (PC) levels and δ-aminolevulinate dehydratase (δ-ALA-D) activity were carried out in rat brain homogenate. The thiol peroxidase-like activity and DPPH radical scavenging of telluroacetylenes a–d were investigated. In in vivo experiments, mice received SNP (0.335 µmol per site) intra cerebroventricular (i.c.v.) thirty minutes after oral administration of telluroacetylene b (10 mg/kg). After 1 h, animals were euthanized. The levels of LP and δ-ALA-D, catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST) activities were carried out in mouse brain homogenate.Key findingsTelluroacetylenes a–d, at low μM range, reduced LP and PC levels in rat brain homogenate. Telluroacetylenes a–d showed effect of scavenging DPPH radicals. δ-ALA-D activity was inhibited by telloruacetylenes a–d, at high μM range, in rat brain homogenate. Brains of mice treated with SNP showed an increase in LP and the reduction in δ-ALA-D, GR and GST activities. Telluroacetylene b protected against the oxidative stress caused by SNP in brain of rats.SignificanceThe results support an antioxidant effect of telluroacetylenes a–d in vitro. Telluroacetylene b protected against oxidative damage caused by SNP in mouse brain, suggesting an antioxidant effect of this compound.     

Ligustrazine Phosphate Ethosomes for Treatment of Alzheimer’s Disease, In Vitro and in Animal Model Studies

In the present study, we have investigated transdermal administration of ligustrazine phosphate (LP), as an antioxidant, for the treatment of Alzheimer's disease (AD). The LP transdermal ethosomal system was designed and characterized. Franz-type diffusion cells and confocal laser scanning microscopy were used for the in vitro permeation studies. Furthermore, the effect of LP transdermal ethosomal system on AD was evaluated in the scopolamine-induced amnesia rats by evaluating the behavioral performance in the Morris water maze test. The activities of the antioxidant enzymes and the levels of the lipid peroxidation product malondialdehyde (MDA) in the brain of rats were also determined. The results showed that both the penetration ability and the drug deposition in skin of the LP ethosomal system were significantly higher than the aqueous one. The LP transdermal ethosomal system could recover the activities of the antioxidant enzymes and the levels of MDA in the brain of the amnesic rats to the similar status of the normal rats, which was also indirectly reflected by the improvement in the behavioral performance. In conclusion, LP might offer a potential alternative therapeutic drug in the fight against AD, and ethosomes could be vesicles of choice for transdermal delivery of LP.     

Activation of endogenous lipid peroxidation in the brain in oxidation stress caused by administration of iron and its prevention by vitamin E

Looking for an appropriate model of accelerated aging in vivo we investigated the content of endogenous products of lipid peroxidation (LP) in the rat brain after single or 4 day-lasting intramuscular injection of complex-bind iron (ferum Hausman, 50 mg/kg body weight) like promoter of LP. We found that the single administration of this iron complex fails to induce endogenous LP; after 4 day-application of iron we observed significant increase in content of primary (lipid peroxides) and final (fluorescent) products of LP. Iron-promoted activation of endogenous LP could be abolished by animal pretreatment with the natural antioxidant alpha-tocopherol. The calcium antagonist nifedipine didn't affect the content of endogenous LP products neither alone nor in combination with alpha-tocopherol.     

Inhibition of Ca-induced calcium release from mitochondria by antiischemic phenol-based antioxidants

Effects of different inhibitors of lipid peroxidation (LP), such as sulphur-containing oligoquinone hypoxen, natural flavonoid dihydroquercetin (DHQ), and β-ionol, on Ca²⁺-induced calcium release from rat liver mitochondria (RLM) were investigated during oxidation of various substrates. The hypothesis about interrelation between antioxidant properties and influence of selected substances on spontaneous calcium release from mitochondria was verified. Degree of antioxidant activity of the selected substances was estimated by the inhibition of LP induced by Fe²⁺/ATP complex in phospholipid emulsion or in rat liver mitochondria (RLM). According to the inhibition efficacy the investigated substances were ordered as follows: β-ionol ≫ hypoxen > DHQ. 50% inhibition of oxygen consumption during LP of phospholipid emulsion was reached in presence of 3.2 ± 0.6 μM of β-ionol, 15.0 ± 1.1 μM of hypoxen, or 19.8 ± 1.7 μM of DHQ. Among the investigated antioxidants hypoxen only decreased spontaneous release of calcium from RLM after calcium accumulation by RLM. The impact of the antioxidants onto calcium current depended on the oxidized substrate. Hypoxen effect was most expressed during the oxidation of NAD-dependent substrate. The direct relationship between the antioxidant activity of the selected antioxidants and their influence on calcium transport in RLM was not revealed. The results indicate that the choice of antiischemic preparations should not only rely on their antioxidant activities.     

The sexual function of mature rat males after prenatal modulation of cholinergic system

The data obtained have shown that prenatal exposure of pregnant rat females of 9-19-day pregnancy to N-cholinolytics as compared to M-cholinolytics produce long-term behavioural changes in pubescent rat progeny. Pubescent rat progeny had low dynamics of gaining sexual experience and decreased sexual activity with equal disturbance of motivation and coitus. The number of males with absence of sexual activity was above that of the control group. We suggest that sexual dysfunction of offspring adulthood was provoked by introduction of ganglerone (N-cholinolytic) which had been injected on 9-11 and 12-14 days of gestation, and metamyzil (M-cholinolytic) injected on 9-11 days of gestation. Apparently, regulation of neuronal mechanisms for sexual function is disturbed as a consequence of lasting change in neurotransmitter activity. It is suggested that dopaminergic activity in brain limbic structures was affected the most. The significant decrease in blood testosterone values has also been elucidated.     

Comparative study on the influence of fluoride on lipid peroxidation and antioxidants levels in the different brain regions of well-fed and protein undernourished rats

Effects of fluoride on the levels of Lipid peroxidation (LP) and antioxidant enzymes in the brain regions of protein undernourished (PU) and well-fed rats (WF) rats exposed to 100 ppm fluoride in drinking water were investigated. The results indicate that the mean body weights and the total brain weights of PU rats as well as those given fluoride (both WF and PU) were significantly (P < 0.05) lower than their respective controls. The weights of different brain regions were also significantly reduced (P < 0.05) in PU rats compared to WF rats except in the brain stem. Fluoride ingestion diminished the weights of WF and PU rats affecting the cerebrum only (in the case of PU rats) and the cerebellum of both WF and PU rats without an effect on the brain stem of both WF and PU. Additionally, increased LP was observed in the cerebrum and cerebellum of PU rats but after fluoride ingestion, 30% increase in LP was observed only in the cerebrum. In the brain stem however, protein undernutrition was accompanied with a significant reduction in LP but the region seems insensitive to fluoride. There were significant reductions (P < 0.05) in CAT, SOD and GSH in all the brain regions (except the GSH level in the brain stem only) of PU rats. Fluoride induced reduction in the activity of CAT in the three brain regions and on SOD activity in cerebrum only for WF rats but no effect of fluoride on all the antioxidants studied in the three brain regions for PU rats. It is concluded that WF and PU rats responded differently to fluoride toxicity. However, it seems that at the dosage used, fluoride toxicity may be a direct effect on the antioxidant enzymes.     

Enhancement of In Vivo Antioxidant Ability in the Brain of Rats Fed Tannin

The effect of the oral administration of mimosa tannin (MMT) on the rat intra-hippocampal antioxidant ability was examined. Wistar rats at the age of 6 weeks were reared for 8 weeks with the rodent diet (RD) consisting of 0.1 g/kg of MMT (RD–MMT). The antioxidant ability of rat brain was evaluated from the decay of a brain–blood-barrier permeable stable nitroxide, 3-methoxycarbonyl-2,2,5,5-tetramethylpyrrolidine-1-oxyl (PCAM) measured by the microdialysis-electron spin resonance system under a freely moving state. The decay rate of PCAM in the brain of rats fed RD–MMT was significantly larger than that of rats fed control rodent diet, which indicates the increase of the antioxidant ability in the brain of rats fed RD–MMT. In vitro study showed that MMT did not reduce PCAM directly but enhanced the reduction of PCAM by ascorbic acid. These results indicate that MMT is a potent antioxidant in vitro and in vivo.     

Protective Effects of Lamotrigine,Aripiprazole and Escitalopram on Depression-induced Oxidative Stress in Rat Brain

We investigated the effects of lamotrigine, aripiprazole and escitalopram administration and experimental depression on lipid peroxidation (LP) and antioxidant levels in cortex of the brain in rats. Forty male wistar rats were randomly divided into five groups. First group was used as control although second group was depression-induced group. Aripiprazole, lamotrigine and escitalopram per day were orally supplemented to chronic mild stress (CMS) depression-induced rats constituting the third, fourth and fifth groups for 28 days, respectively. Depression resulted in significant decrease in the glutathione peroxidase (GSH-Px) activity, reduced glutathione and vitamin C of cortex of the brain although their levels and beta-carotene concentrations were increased by the three drugs administrations to the animals of CMS induced depression group. The LP levels in the cortex of the brain and plasma of depression group were elevated although their levels were decreased by the administrations. The increases of antioxidant values in lamotrigine group were higher according to aripiprazole and escitalopram supplemented groups. Vitamin A level did not change in the five groups. In conclusion, the experimental depression is associated with elevated oxidative stress although treatment with lamotrigine has most protective effects on the oxidative stress within three medicines.     

Ability of Human Leukocytic Pyrogen to Stimulate Brain Prostaglandin Synthesis In Vitro

Abstract: Fever is thought to be mediated by leukocytic pyrogen (LP), a polypeptide synthesized by phagocytic leukocytes and which is responsible for the upwards resetting of the hypothalamic thermostat. In an attempt to study the effects of LP directly on brain tissue, purified human LP was incubated with rabbit brain slices in vitro. Because of the well-documented role of prostaglandin (PG) synthesis in both the production of fever and antipyresis, PGE levels were measured on the supernates of brain slices incubated 30 min with LP. Levels of PGE increased 3- to 4-fold in rabbit anterior and posterior hypothalami. In addition, PGE levels were similarly increased in temporal cortex slices when exposed to LP. In another set of experiments, PGE levels increased 4- to 5-fold when brain tissue was incubated with a highly purified preparation of bacterial endotoxin (ET). The ability of ET to increase brain PGE levels was not affected by moderate heating (56°C, 30 min), whereas this temperature destroyed the PGE-inducing properties of LP. The antipyretic ibuprofen markedly reduced the amount of PGE measured in the brain slice supernates after stimulation with LP, suggesting that LP brings about synthesis of PGE and not the release of preformed PG. The results demonstrate that LP is a potent inducer of PGE synthesis in rabbit brain and that receptors for LP are not restricted to the thermoregulatory center, but rather may be distributed throughout the brain.     

Involvement of nitric oxide in noradrenaline-induced changes in the activity of antioxidant enzymes and lipid peroxidation in rat brown adipose tissue and heart

The effect of exogenous noradrenaline (NA) (1.6 mg.kg(-1) i.p., 35 min prior sacrifice) on the activity of antioxidant enzymes (AOE) copper zinc superoxide dismutase (CuZnSOD), manganese superoxide dismutase (MnSOD) and catalase (CAT), as well as lipid peroxides (LP) concentration were studied in the rat interscapular brown adipose tissue (IBAT) and heart of saline (controls) and N(omega)-nitro-L-arginine methyl ester (L-NAME) treated rats (10 mg.kg(-1), i.p., during 3 days and 20 min before NA). NA differently affects both AOE activities and LP production in the IBAT and heart. Thus, NA inhibited the activity of all IBAT AOE and LP production while in the heart it markedly increased CAT activity only, but had no effect on any of SODs activities and LP concentration. L-NAME, a nitric oxide synthase blocker, completely abolished the NA-induced inhibition of the IBAT AOE and LP production, whereas in the heart it was without effect. In conclusion, these results indicate that both NA and L-NAME effects on AOE activity and LP production are tissue specific and also suggest that nitric oxide mediates the NA-induced inhibition of AOE activity and LP production in the IBAT only.     

Ceftriaxone ameliorates cyclosporine A-induced oxidative nephrotoxicity in rat

A growing body of evidence now suggested that cyclosporine A (CycA)‐induced nephrotoxicity is a crucial clinical problem and oxidative stress is importantly responsible for its toxicity. Ceftriaxone induced antioxidant effect in brain and neuronal tissues against oxidative damage although its antioxidant potential effect on kidney has not been clarified. The aim of this study was to evaluate whether ceftriaxone protects CycA‐induced oxidative stress kidney injury in rats. Twenty‐four rats were equally divided into four groups. First group was used as control. Ceftriaxone (200 mg/kg) and CycA (15 mg/kg) were administrated to second and third groups for 10 days, respectively. The ceftriaxone and CycA combination was given to rats constituting the fourth group for 10 days. Lipid peroxidation (LP), urea nitrogen and lactate dehydrogenase (LDH) levels were higher in CycA group than in control and ceftriaxone groups although LP, urea nitrogen and LDH levels were lower in ceftriaxone + CycA group than in control and ceftriaxone groups. Glutathione peroxidase and catalase activities were lower in CycA group than in control whereas their activities were increased in control and ceftriaxone groups. Superoxide dismutase activity did not change by the treatments. Ceftriaxone administration recovered also CycA‐induced atrophy, vacuolization and exfoliations of tubular epithelium and glomerular collapse in histopathological evaluation of kidney. In conclusion, we observed that ceftriaxone is beneficial on CycA‐induced oxidative stress in kidney of rats by modulating oxidative and antioxidant system. Copyright © 2011 John Wiley & Sons, Ltd.     

Participation of cholinergic mechanisms in realizing the effects of bicuculline]

Screening and electrophysiological methods were applied to the verification of the hypothesis on a possibility of participation of cholinergic structures in the realization of bicucullin effects. M- and N-cholinolytics (benactizine, atropine, aprophen, and pediphen) failed to arrest the convulsions induced in mice by bicucullin adminstration. At the same time substances inducing accumulation of gamma-aminobutyric acid (GABA) in the brain, i.e. aminooxycetic acid and depakin produced a manifest protective action in convulsions caused by bicucullin administration. In electrophysiological experiments there was also revealed an incapacity of M-cholinolytic benaltizine to arrest the bicucullin effects. Bicucullin proved to diminish depression of the test response in the restoration cycle of the primary response of the rat sensory motor cortex at the intervals of 40--125ms between the stimuli, whereas benactizine decreased the late facilitation of the test response at the intervals of 150--300ms between the stimuli. There was also noted no interaction between benactizine and bicucullin by this test. On the basis of these data a conclusion was drawn that bicucullin effects were caused by the block of postsynaptic GABA receptors, and were not connected with the cholinergic structures activity.     

Effect of dietary sesame oil as antioxidant on brain hippocampus of rat in focal cerebral ischemia

Oxidative stress may be regarded as an imbalance between free radical production and opposing antioxidant defenses. Free radical oxidative stress is implicated in rat cerebral ischemia and naturaceutical antioxidants are dietary supplements that have been reported to have neuroprotective activity. Many studies have reported dietary sesame oil (SO) as an effective antioxidant. In the present study the neuroprotective effect of dietary SO was evaluated against middle cerebral artery occlusion (MCAO)-induced cerebral ischemia injury in rats. Rats were fed on diet (20% SO) for 15 days. The middle cerebral artery of adult male Wistar rat was occluded for 2 h and reperfused for 22 h. The antioxidant properties of brain were measured as levels of reduced glutathione (GSH), glutathione-S-transferase (GST), glutathione peroxide (GPx), glutathione reductase (GR), catalase (CAT), superoxide dismutase (SOD) and thiobarbituric acid reactive substance (TBARS). A decrease in the activity of all the enzymatic and non-enzymatic antioxidants was observed along with an increase in lipid peroxidation (LPO) in MCAO group. The neurobehavioral activity of rats was also observed by using videopath analyzer. Dietary SO improved the antioxidant status in MCAO+SO group when compared with MCAO group. The results of neurobehavioral activity also support our biochemical data. The results obtained suggest protective effect of SO against cerebral ischemia in rat brain through their antioxidant properties.     

Acetaminophen at Different Doses Protects Brain Microsomal Ca2+-ATPase and the Antioxidant Redox System in Rats

Acetaminophen, an analgesic and antipyretic drug, rescues neuronal cells from mitochondrial redox impairment and reactive oxygen species (ROS). Excessive administration of acetaminophen above the recommended daily dose range has some negative effects on the brain. We investigated the effects of different doses of acetaminophen on Ca²⁺-ATPase and the antioxidant redox system in rats. Seventy rats were randomly divided into seven equal groups. The first was used for the control. One dose of 5, 10, 20, 100, 200, and 500 mg/kg acetaminophen was intraperitoneally administered to rats constituting the second, third, fourth, fifth, sixth, and seventh groups, respectively. After 24 h, brain cortical samples were taken and brain microsomal samples were obtained by ultracentrifugation. Brain and microsomal lipid peroxidation (LP) and brain calcium levels in the sixth and seventh groups were increased compared to control. LP levels in the second, third, and forth groups; brain vitamin E levels; brain and microsomal glutathione peroxidase (GSH-Px); and Ca²⁺-ATPase activity in the sixth and seventh groups were lower than in control, although brain vitamin E concentrations in the second, third, fourth, and fifth groups and microsomal GSH-Px activity in the third and fourth groups were higher than in control. Brain cortical β-carotene and vitamin A concentrations did not differ in the seven groups. In conclusion, 5–100 mg/kg acetaminophen seems to have protective effects on oxidative stress-induced brain toxicity by inhibiting free radicals and supporting the antioxidant redox system.     

Effects of proteasome inhibitor, MG132, on proteasome activity and oxidative status of rat liver

In vivo effects of N-benzyloxycarbonyl (Cbz)-Leu-Leu-leucinal (MG132) on chymotryptic-like (ChT-L), tryptic-like, and post-glutamyl peptide hydrolytic-like proteasome activities, protein oxidation, lipid peroxidation (LP), glutathione (GSH) level, as well as on the activity of antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and glutathione-reductase) in the rat liver were studied. The possibility of MG132 provoking the formation of free oxygen radicals was also assayed in primary hepatocytes. The following results were obtained: (1) In vivo, MG132 did not change the spontaneous LP, but increased Fe-induced LP and the amount of oxidized proteins; it decreased the GSH level in liver. From the proteasome activities studied in liver cytosol only ChT-L activity was significantly decreased after MG132 administration. Furthermore, MG132 increased antioxidant enzyme activities of SOD, CAT, and GSH-Px. (2) In vitro, MG132 increased free radical oxygen species in hepatocytes; this effect disappeared in the presence of CAT or mannitol. In conclusion, since nowadays proteasome inhibitors are entering into the swing of laboratory and clinical practice, the present data could provide useful information for MG132 action. Consequently, future in vivo experiments with MG132 could highlight the possibility of its use at different pathological conditions.     

Synthesis of N-substituted indole-2-carboxamides and investigation of their biochemical responses against free radicals

The antioxidant role of novel N-substituted indole-2-carboxamides (I2CDs) was investigated for their inhibitory effects on superoxide anion (O2-) and lipid peroxidation (LP). Among the synthesized I2CDs, 3, 4, 6, 8 and 9 significantly inhibited O2*- with an inhibition range at 70-98%. Examination of substituent effects on activity showed that both the ortho- and para- positions of the benzamide residue needs to be dichlorinated in order to get a maximum inhibitory effect on superoxide anion. In general, halogenated derivatives were found more active then the non-halogenated ones. However, none of the I2CDs had a significant inhibitory effects on the level of lipid peroxidation; only compounds 7 and 10 moderately decreased LP levels by over 50% at 10(-3) M concentrations.     

Effect of cholinolytic and adrenergic blocking preparations on rat erythrocyte resistance to hypo-osmotic hemolysis]

The influence of central cholinolytics and adrenoblocking drugs on the hemolysis of rat erythrocytes in the hypoosmotic buffer was studied in vitro. At pH 7.4 in a concentration of 10(-4) M central cholinolytics ethyl-dipracil, diphacil, pediphen, tropacin, and beta-adrenoblocking agent propranolol protected the erythrocytes from hemolysis most intensively. The central M-cholinlytics amizyl, glypin, and alpha-adrenoblocking agents purroxan, sympatholytin, phentolamin were less active. The antihemolytic effect of drugs reached the maximum in the course of 30 minutes, and was maintained for several hours. The protection of erythrocytes from hemolysis by drugs containing tertiary nitrogen was greater. Prevention of the hypoosmotic hemolysis pointed to the stabilization of the erythrocyte membrane by the preparations examined. In the mechanism of action of the central N-cholinolytics and beta-adrenoblocking drugs it is necessary to consider the possibility of stabilization of the membrane formations containing no synaptic contacts.     

Effect of Emblica officinalis tannoids on a rat model of tardive dyskinesia

Effect of active tannoid principles of E. officinalis, comprising of emblicanin A (37%), emblicanin B (33%), punigluconin (12%) and pedunculagin (14%), was investigated on a rat model of tardive dyskinesia (TD) induced by once daily administration of haloperidol (1.5 mg/kg, ip) for 28 days. Involuntary orofacial movements (chewing movements, buccal tremors and tongue protusion) were assessed as TD parameters. The tannoid principles of E. officinalis (EOT) were administered concomitantly with haloperidol in the doses of 10, 20 and 50 mg/kg, po, for 28 days. Sodium valproate (200 mg/kg, po), a Gaba-mimetic agent, and vitamin E (400 mg/kg, po), an antioxidant, were used as the standard drugs and administered for the same period. EOT induced a dose-related inhibition of all the three TD parameters assessed, as did vitamin E. The effect of sodium valproate remained statistically insignificant. The results suggest that EOT exerts a prophylactive effect against neuroleptic-induced TD which is likely to be due to its earlier reported antioxidant effects in rat brain areas, including striatum.     

Activity of antioxidant enzymes in enterocytes of the small intestine and blood cells after ionizing irradiation and administration of vitamin E in rats

The long-term influence of low X-ray irradiation increases lipid peroxidation (LP) in radiosensitive (bone marrow, enterocytes of small intenstine) and in relatively radioresistant blood cells (erythrocytes). The activation of antioxidant system enzymes in observed cells does not decrease LP intensity. We concluded that additional administration of alpha-tocopherol provided the decrease of the first and end products of LP in the observed tissues mostly in the beginning of the experiment. Antioxidant effect of the preparation is more significant in cells with high proliferative activity but normal activity of enzymes was not determined.     

Effects of Extremely Low-Frequency Magnetic Field on Caspase Activities and Oxidative Stress Values in Rat Brain

This study was aimed to investigate the effect of extremely low-frequency magnetic field (ELF-MF) on apoptosis and oxidative stress values in the brain of rat. Rats were exposed to 100 and 500 µT ELF-MF, which are the safety standards of public and occupational exposure for 2 h/day for 10 months. Brain tissues were immunohistochemically stained for the active (cleaved) caspase-3 in order to measure the apoptotic index by a semi-quantitative scoring system. In addition, the levels of catalase (CAT), malondialdehyde (MDA), myeloperoxidase (MPO), total antioxidative capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) were measured in rat brain. Final score of apoptosis and MPO activity were not significantly different between the groups. CAT activity decreased in both exposure groups (p?<?0.05), while TAC was found to be lower in ELF 500 group than those in ELF-100 and sham groups (p?<?0.05). MDA, TOS, and OSI values were found to be higher in ELF-500 group than those in ELF-100 and sham groups (p?<?0.05). In conclusion, apoptosis was not changed by long-term ELF-MF exposure, while both 100 and 500 µT ELF-MF exposure induced toxic effect in the rat brain by increasing oxidative stress and diminishing antioxidant defense system.