Neonatal handling prevents anxiety-like symptoms in rats exposed to chronic mild stress: behavioral and oxidative parameters.

This study investigated the influence of neonatal handling on behavioral and biochemical consequences of chronic mild stress (CMS) in adulthood. Male rat pups were submitted to daily tactile stimulation (TS) or maternal separation (MS), from postnatal day 1 (PND1) to postnatal day 21 (PND21), for 10 min/day. In adulthood, half the number of animals were exposed to CMS for 3 weeks and submitted to behavioral testing, including sucrose preference (SP), elevated plus maze (EPM), and defensive burying tasks (DBTs), followed by biochemical assessments. CMS reduced SP, increased anxiety in EPM and DBT, and increased adrenal weight. In addition, CMS decreased plasma vitamin C (VIT C) levels and increased protein carbonyl (PC) levels, catalase (CAT) activity in hippocampus and cortex, and superoxide dismutase (SOD) levels in cortex. In contrast, both forms of neonatal handling were able to prevent reduction in SP, anxiety behavior in DBT, and CMS-induced adrenal weight increase. Furthermore, they were also able to prevent plasma VIT C reduction, hippocampal PC levels increase, CAT activity increase in hippocampus and cortex, and SOD levels increase in cortex following CMS. Only TS was able to prevent CMS-induced anxiety symptoms in EPM and PC levels in cortex. Taken together, these findings show the protective role of neonatal handling, especially TS, which may enhance ability to cope with stressful situations in adulthood.

Antioxidant protection of gallic acid against toxicity induced by Pb in blood, liver and kidney of rats.

The effect of the antioxidant gallic acid (GA) on Pb toxicity in blood, liver and kidney was investigated in the present study. Rats Wistar received Pb nitrate (50 mg/Kg/day, i.p., 5 days) followed by GA (13.5 mg/Kg, p.o., 3 days) or a chelating agent (EDTA, 55 mg/Kg, i.p.). As result, Pb decreased body weight, hematocrit and blood δ-aminolevulinic acid dehydratase (ALA-D) activity. In addition, high Pb levels were observed in blood and tissues, together with increased (1) lipid peroxidation in erythrocytes, plasma and tissues, (2) protein oxidation in tissues and (3) plasma aspartate transaminase (AST) levels. These changes were accompanied by decreasing in antioxidant defenses, like superoxide dismutase (SOD) activity in tissues and catalase (CAT) activity and reduced glutathione (GSH) in liver. GA was able to reverse Pb-induced decrease in body weight and ALA-D activity, as well as Pb-induced oxidative damages and most antioxidant alterations, however it did not decrease Pb bioaccumulation herein as EDTA did. Furthermore, EDTA did not show antioxidant protection in Pb-treated animals as GA did. In conclusion, GA decreased Pb-induced oxidative damages not by decreasing Pb bioaccumulation, but by improving antioxidant defenses, thus GA may be promising in the treatment of Pb intoxications.

Toxicological aspects of trans fat consumption over two sequential generations of rats: Oxidative damage and preference for amphetamine.

Chronic consumption of processed food causes structural changes in membrane phospholipids, affecting brain neurotransmission. Here we evaluated noxious influences of dietary fats over two generations of rats on amphetamine (AMPH)-conditioned place preference (CPP). Female rats received soybean oil (SO, rich in n-6 fatty acids (FA)), fish oil (FO, rich in n-3 FA) and hydrogenated vegetable fat (HVF, rich in trans fatty acids (TFA)) for two successive generations. Male pups from the 2nd generation were maintained on the same supplementation until 41 days of age, when they were conditioned with AMPH in CPP. While the FO group showed higher incorporation of n-3 polyunsaturated-FA (PUFA) in cortex/hippocampus, the HVF group showed TFA incorporation in these same brain areas. The SO and HVF groups showed AMPH-preference and anxiety-like symptoms during abstinence. Higher levels of protein carbonyl (PC) and lower levels of non-protein thiols (NPSH) were observed in cortex/hippocampus of the HVF group, indicating antioxidant defense system impairment. In contrast, the FO group showed no drug-preference and lower PC levels in cortex. Cortical PC was positively correlated with n-6/n-3 PUFA ratio, locomotion and anxiety-like behavior, and hippocampal PC was positively correlated with AMPH-preference, reinforcing connections between oxidative damage and AMPH-induced preference/abstinence behaviors. As brain incorporation of trans and n-6 PUFA modifies its physiological functions, it may facilitate drug addiction.

Tactile stimulation and neonatal isolation affect behavior and oxidative status linked to cocaine administration in young rats.

We investigated the influence of neonatal handling on cocaine-induced conditioned place preference (CPP), anxiety-like symptoms and oxidative status related to drug abstinence in young rats. Pups were submitted to tactile stimulation (TS) or neonatal isolation (NI10 or NI60) after birth, and then were submitted to CPP performed with cocaine. TS group did not show place preference, while unhandled (UH), NI10 and NI60 rats did. Handling was related to anxiety-like symptoms per se in UH and NI60 groups and this behavior was also observed in the cocaine-conditioned rats exposed to the same handlings. Both TS and NI10 pups treated or not with cocaine showed less anxiety-like behavior than animals submitted to other handlings. TS reduced protein carbonyl (PC) in cortex and NI60 increased PC in both striatum and hippocampus of cocaine-treated rats. Among cocaine-treated rats, both times of NI increased plasma lipoperoxidation levels, which was reduced by TS in erythrocytes. TS increased the catalase activity in brain areas, while other handlings did not change this. Both TS and NI10 increased plasma vitamin C levels. These findings indicate that neonatal handling can modify anxiety-like symptoms related to cocaine preference and abstinence, and its protective influence, especially TS, on the antioxidant system.

Influence of neonatal tactile stimulation on amphetamine preference in young rats: parameters of addiction and oxidative stress.

This study investigated the influence of neonatal handling on amphetamine-induced conditioned place preference (CPP), as well as the consequent anxiety-like symptoms and oxidative status related to drug abstinence in young rats. Male pups were exposed to tactile stimulation (TS) or neonatal isolation (NI) for 10 min every day from postnatal day one (PND1) to PND21. After being weaned (PND22), pups were separated by handling type until PND40, when treatment with amphetamine (AMPH-4 mg/kg/mL ip, for 8 days) or vehicle (NaCl 0.9% ip, 1 mL/Kg) in CPP started. AMPH-conditioning evoked drug-preference (in 24h and 96 h) and abstinence symptoms in unhandled (UH) animals, followed by oxidative damage in the cortex, hippocampus and striatum. TS showed beneficial influence, as observed by the decreased drug-preference (24 and 96 h) in relation to UH and NI, showing no abstinence symptoms in this last period, as observed by the reduced anxiety-like symptoms. The oxidative status indicated a protective influence of TS on brain tissues: lower lipid peroxidation (LP) and reduced protein carbonylation (PC) in the cortex, hippocampus and striatum. Furthermore, TS also increased antioxidant defenses in brain tissues and blood: i) increased plasma levels of vitamin C; ii) increased activity of catalase (CAT) and iii) higher levels of glutathione (GSH) in red blood cells (RBC). Moreover, there were positive correlations of AMPH-CPP with PC and LP levels in all the brain areas assessed. In summary, TS modifies AMPH-preference in the CPP paradigm, reducing drug abstinence behaviors, and stimulating the antioxidant defense system, thus protecting the brain areas closely related to addiction in young rats. Studies about TS and addiction in animal models should be extended to the molecular level.

Influence of trans fat and omega-3 on the preference of psychostimulant drugs in the first generation of young rats.

The current Western diet often provides considerable amounts of saturated and trans fatty acids (TFA), whose incorporation into neuronal membranes has been implicated in changes of brain neurochemical functions. Such influence has caused concerns due to precipitation of neuropsychiatric disorders, whose data are still unclear. Here we evaluated the influence of different fats on preference parameters for amphetamine (AMPH): adolescent rats were orally supplemented with soybean oil (SO, rich in n-6 FA, which was considered an isocaloric control group), fish oil (FO, rich in n-3 FA) and hydrogenated vegetable fat (HVF, rich in saturated and trans FA) from weaning, which were born of dams supplemented with the same fat from pregnancy and lactation. AMPH preference, anxiety-like symptoms and locomotor index were evaluated in conditioned place preference (CPP), elevated plus maze (EPM) and open-field (OF), respectively, while brain oxidative status was determined in cortex, striatum and hippocampus. HVF increased AMPH-CPP and was associated with withdrawal signs, as observed by increased anxiety-like symptoms. Moreover, SO and FO were not associated with AMPH preference, but only FO-supplemented rats did not show any anxiety-like symptoms or increased locomotion. FO supplementation was related to lower oxidative damages to proteins and increased CAT activity in striatum and hippocampus, as well as increased GSH levels in blood, while HVF was related to increased oxidative status. In conclusion, our study showed the harmful influence of TFA on AMPH-CPP and drug craving symptoms, which can be related to dopaminergic neurotransmission.

Hepatoprotective effects of pecan nut shells on ethanol-induced liver damage.

The hepatoprotective activity of the aqueous extract of the shells of pecan nut was investigated against ethanol-induced liver damage. This by-product of the food industry is popularly used to treat toxicological diseases. We evaluated the phytochemical properties of pecan shell aqueous extract (AE) and its in vitro and ex vivo antioxidant activity. The AE was found to have a high content of total polyphenols (192.4±1.9 mg GAE/g), condensed tannins (58.4±2.2 mg CE/g), and antioxidant capacity, and it inhibited Fe(2+)-induced lipid peroxidation (LP) in vitro. Rats chronically treated with ethanol (Et) had increased plasmatic transaminases (ALT, AST) and gamma glutamyl transpeptidase (GGT) levels (96%, 59.13% and 465.9%, respectively), which were effectively prevented (87; 41 and 383%) by the extract (1:40, w/v). In liver, ethanol consumption increased the LP (121%) and decreased such antioxidant defenses as glutathione (GSH) (33%) and superoxide dismutase (SOD) (47%) levels, causing genotoxicity in erythrocytes. Treatment with pecan shell AE prevented the development of LP (43%), GSH and SOD depletion (33% and 109%, respectively) and ethanol-induced erythrocyte genotoxicity. Catalase activity in the liver was unchanged by ethanol but was increased by the extract (47% and 73% in AE and AE+Et, respectively). Therefore, pecan shells may be an economic agent to treat liver diseases related to ethanol consumption.

Haloperidol-loaded polysorbate-coated polymeric nanocapsules decrease its adverse motor side effects and oxidative stress markers in rats.

Haloperidol is the most widely used antipsychotic drug in the treatment of psychiatric disorders. Despite its satisfactory therapeutic effect, its chronic use is related to severe motor side effects. Here, we investigate the incidence of motor side effects of haloperidol-loaded nanocapsules when compared to free haloperidol and the relation with oxidative stress (OS) development. Both vehicle (B-NcFO) and haloperidol loaded polysorbate-coated nanocapsules suspension (H-NcFO) prepared with fish oil as core showed uniform and rounded particles, nanometric size, negative zeta potential, low polydispersity indices and high encapsulation efficiency. Wistar rats received a single dose of free haloperidol (FH), B-NcFO or H-NcFO (0.2 mg/kg ip) and were submitted to acute motor side effects evaluation 1 h after the injection. Lower catalepsy time and oral dyskinesia were observed in H-NcFO-treated group than in FH group; however, both formulations decreased animals' locomotor activity. In a experiment performed subchronically, rats injected daily with H-NcFO (0.2 mg/kg-ip) for 28 days showed decreased oral dyskinesia frequency and catalepsy time and no impairment on locomotor activity as compared to FH group (0.2 mg/kg-ip). FH group showed higher OS, as observed by increased lipid peroxidation and reduced glutathione levels and catalase activity in extrapyramidal region. Our findings showed that nanocapsules may be an efficient form to prevent or minimize haloperidol motor side effects, which are related to OS development, ameliorating psychiatric patients' quality of life.

Neonatal tactile stimulation changes anxiety-like behavior and improves responsiveness of rats to diazepam.

In this study we evaluated the influence of neonatal tactile stimulation (TS) on behavioral and biochemical effects related to a low dose of diazepam (DZP) in adult rats. Male pups of Wistar rats were handled (TS) daily from PND1 to PND21 for 10 min, while unhandled (UH) rats were not touched. In adulthood, half the animals of each group received a single administration of diazepam (0.25mg/kg body weight i.p.) or vehicle and then were submitted to behavioral and biochemical evaluations. In the TS group, DZP administration reduced anxiety-like symptoms in different behavioral paradigms (elevated plus maze, EPM; staircase and open-field and defensive burying) and increased exploratory behavior. These findings show that neonatal TS increased DZP pharmacological responses in adulthood compared to neonatally UH animals, as observed by reduced anxiety-like symptoms and lower levels of plasma cortisol. TS also changed plasma levels of antioxidant defenses such as vitamin C and glutathione peroxidase, whose increase may be involved in lower oxidative damages to proteins in cortex, subthalamic region and hippocampus of these animals. Here we are showing for the first time that neonatal TS is able to change responsiveness to benzodiazepine drugs in adulthood and provides better pharmacological responses in novel situations of stress.

Haloperidol-loaded polysorbate-coated polymeric nanocapsules increase its efficacy in the antipsychotic treatment in rats.

Haloperidol is an antipsychotic drug associated with the development of movement disorders. We evaluated the effect of its nanoencapsulation on its pharmacological activity and motor side effects. Haloperidol-loaded polysorbate-coated nanocapsules (H-NC) showed nanometric size, negative zeta potential and low polydispersity indices and high encapsulation efficiency (>95%). Rats received a single dose of H-NC (0.2mg/kg ip) and four doses of D,L-amphetamine, AMPH (8.0mg/kg ip), injected every 3h (0, 3, 6 and 9h). The AMPH-induced stereotyped movements were quantified in the intervals of 15 min after each of four doses of AMPH, demonstrating greater pharmacological efficacy of the H-NC over free haloperidol (FH). The acute motor side effects were evaluated 1h after a single dose of H-NC or its free solution (0.2mg/kg ip). The group treated with H-NC presented lower extrapyramidal effects (catalepsy and oral dyskinesia) than those treated with FH. In the last experimental set, rats sub-chronically treated with a daily dose of H-NC (0.2mg/kg ip) for 28 days showed a lower incidence of extrapyramidal effects than those treated with the free drug (0.2mg/kg ip). Our findings showed the potential of using H-NC in the development of a nanomedicine aimed at increasing the efficacy of this antipsychotic drug and reducing its side effects.

Short term dietary fish oil supplementation improves motor deficiencies related to reserpine-induced parkinsonism in rats.

Fish oil (FO) supplementation could cause an increase in the concentration of plasmatic free fatty acids and, consequently, could compete with pro-inflammatory arachidonic acid (ARA) derived from brain biomembranes metabolism in the cerebrospinal fluid. Essential fatty acids (EFA) (n-3) have been reported by their antioxidant and neuroprotective properties, and therefore the influence of the FO supplementation on the reserpine-induced motor disorders was studied. Wistar rats were orally treated with FO solution for 5 days, and co-treated with reserpine (R; 1 mg/kg/mL) or its vehicle for 3 days (every other day). Reserpine-induced orofacial dyskinesia and catalepsy (P < 0.05) were prevented by FO (P < 0.05). Biochemical evaluations showed that reserpine treatment increased the lipid peroxidation in the cortex and striatum (P < 0.05), while the FO supplementation prevented this oxidative effect in both brain regions (P < 0.05). Our results showed the protective role of FO in the brain lipid membranes, reinforcing the beneficial effect of n-3 fatty acids in the prevention of degenerative and motor disorders.

Locomotor damage and brain oxidative stress induced by lead exposure are attenuated by gallic acid treatment.

We investigated the antioxidant potential of gallic acid (GA), a natural compound found in vegetal sources, on the motor and oxidative damages induced by lead. Rats exposed to lead (50 mg/kg, i.p., once a day, 5 days) were treated with GA (13.5mg/kg, p.o.) or EDTA (110 mg/kg, i.p.) daily, for 3 days. Lead exposure decreased the locomotor and exploratory activities, reduced blood ALA-D activity, and increased brain catalase (CAT) activity without altering other antioxidant defenses. Brain oxidative stress (OS) estimated by lipid peroxidation (TBARS) and protein carbonyl were increased by lead. GA reversed the motor behavior parameters, the ALA-D activity, as well as the markers of OS changed by lead exposure. CAT activity remained high, possibly as a compensatory mechanism to eliminate hydroperoxides during lead poisoning. EDTA, a conventional chelating agent, was not beneficial on the lead-induced motor behavior and oxidative damages. Both GA (less) and EDTA (more) reduced the lead accumulation in brain tissue. Negative correlations were observed between the behavioral parameters and lipid peroxidation and the lead levels in brain tissue. In conclusion, GA may be an adjuvant in lead exposure, mainly by its antioxidant properties against the motor and oxidative damages resulting from such poisoning.

Comparative study between two animal models of extrapyramidal movement disorders: prevention and reversion by pecan nut shell aqueous extract.

Acute reserpine and subchronic haloperidol are animal models of extrapyramidal disorders often used to study parkinsonism, akinesia and tardive dyskinesia. In humans, these usually irreversible and disabling extrapyramidal disorders are developed by typical antipsychotic treatment, whose pathophysiology has been related to oxidative damages development. So far, there is no treatment to prevent these problems of the psychiatric clinic, and therefore further studies are needed. Here we used the animal models of extrapyramidal disorders cited above, which were performed in two distinct experiments: orofacial dyskinesia (OD)/catalepsy induced by acute reserpine and subchronic haloperidol after (experiment 1) and before (experiment 2) oral treatment with pecan shell aqueous extract (AE), a natural and promissory antioxidant. When administered previously (exp.1), the AE prevented OD and catalepsy induced by both reserpine and haloperidol. When reserpine and haloperidol were administered before the extract (exp.2), the animals developed OD and catalepsy all the same. However, the orofacial parameter (but not catalepsy) in both animal models was reversed after 7 and 14 days of AE treatment. These results indicate that, acute reserpine and subchronic haloperidol administrations induced similar motor disorders, although through different mechanisms, and therefore are important animal models to study the physiopathology of extrapyramidal disorders. Comparatively, the pecan shell AE was able to both prevent and reverse OD but only to prevent catalepsy. These results reinforce the role of oxidative stress and validate the two animal models used here. Our findings also favor the idea of prevention of extrapyramidal disorders, rather than their reversal.

Comparative study between n-6, trans and n-3 fatty acids on repeated amphetamine exposure: a possible factor for the development of mania.

In the last decades, foods rich in omega-3 (ω-3) fatty acids (FA) have been replaced by omega-6 (ω-6) and trans FA, which are found in processed foods. The influence of ω-6 (soybean oil--SO), trans (hydrogenated vegetable fat--HVF) and ω-3 (fish oil--FO) fatty acids on locomotor and oxidative stress (OS) parameters were studied in an animal model of mania. Rats orally fed with SO, HVF and FO for 8 weeks received daily injections of amphetamine (AMPH--4 mg/kg/mL-ip) for the last week of oral supplementation. HVF induced hyperactivity, increased the protein carbonyl levels in the cortex and decreased the mitochondrial viability in cortex and striatum. AMPH-treatment increased the locomotion and decreased the mitochondrial viability in all groups, but its neurotoxicity was higher in the HVF group. Similarly, AMPH administration increased the protein carbonyl levels in striatum and cortex of HVF-supplemented rats. AMPH reduced the vitamin-C plasmatic levels of SO and HVF-fed rats, whereas no change was observed in the FO group. Our findings suggest that trans fatty acids increased the oxidative damage per se and exacerbated the AMPH-induced effects. The impact of trans fatty acids consumption on neuronal diseases and its consequences in brain functions must be further evaluated.

Effects of omega-3 essential fatty acids (omega-3 EFAs) on motor disorders and memory dysfunction typical neuroleptic-induced: behavioral and biochemical parameter.

The effects of fish oil supplementation on motor disorders, memory dysfunction, and lipid peroxidation (LP) induced by typical neuroleptics were studied. Wistar rats received a suspension prepared with fish oil containing omega-3 fatty acids, water, and Tween 80 (1%) in the place of drinking water (FO group) or vehicle (C group) for 8 weeks. After 4 weeks of treatment, half of the animals of both groups were treated with haloperidol (H and FO + H groups; experiment 1), fluphenazine (F and FO + F groups; experiment 2), or vehicle (C group), administered once a week (12 mg/kg/im) for 4 weeks, maintaining the treatment with FO. Extrapyramidal motor disorders by haloperidol and fluphenazine were observed by an increase in vacuous chewing movements and catalepsy (P < 0.05). These effects were reduced by FO treatment (P < 0.05). Both neuroleptics displayed impairment in memory retention observed by latency time to find the original location of platform in water-maze task, after 4 days of training performed in the last treatment week. This effect was reduced by FO (P < 0.05) to both haloperidol and fluphenazine treatments. Haloperidol increased the LP in plasma and hippocampus, and these effects were decreased by FO treatment (P < 0.05). Fluphenazine increased the LP in plasma and substantia nigra, which were completely decreased by FO treatment (P < 0.05). The FO decreased the motor disorders, memory dysfunction, and oxidative damage typical neuroleptic-induced. Our results indicate that FO exhibits a neuroprotector role useful on diseases related to oxidative damages, and may be considered in the prevention of motor and memory side effects induced by the antipsychotic treatment.

Amylose content in rice (Oryza sativa) affects performance, glycemic and lipidic metabolism in rats / Teor de amilose do arroz (Oryza sativa) afeta o desempenho, metabolismo glicêmico e lipídico em ratos

This research aimed at evaluating the effect of diets with high, intermediate and low amylose content of rice on performance, glycemic and lipidic metabolism in rats. Male Wistar rats were fed diets with grains of cooked rice of the cultivars 'IRGA 417', 'IRGA 416' and 'MOCHI' with high, intermediate and low amylose content, respectively. Wet and dry fecal production and serum HDL cholesterol were not affected by amylose content. The animals in the treatments with high amylose content ('IRGA 417') presented lower feed intake, body weight gain and apparent digestibility, higher fecal water content and nitrogen excretion, reduced fecal pH, lower postprandial blood glucose response, serum total cholesterol and triglycerides levels and pancreas weight, and higher fasting serum glucose concentration and liver weight. Amylose:amylopectin ratio significantly affects rice starch digestion in the gastrointestinal tract, affecting some biologically relevant parameters.

O objetivo deste trabalho foi avaliar o efeito de dietas com alto, intermediário e baixo teor de amilose sobre o desempenho, metabolismo glicêmico e lipídico em ratos. Foram utilizados ratos machos Wistar alimentados com rações experimentais elaboradas com grãos de arroz cozido das cultivares 'IRGA 417', 'IRGA 416' e 'MOCHI' com alto, intermediário e baixo teores de amilose, respectivamente. A produção de fezes úmidas e secas e colesterol HDL não foram afetados pelo teor de amilose dos grãos. Os animais submetidos ao tratamento com alto teor de amilose (IRGA 417) apresentaram menores consumo, ganho de peso e digestibilidade aparente, maiores umidade nas fezes e excreção de nitrogênio, reduzido pH fecal, concentração plasmática posprandial de glicose, colesterol total, triglicerídeos e peso do pâncreas e maior concentração de glicose no jejum e peso do fígado. A proporção amilose e amilopectina nos grãos afeta significativamente a digestão do amido de arroz no trato gastrointestinal, afetando alguns parâmetros biologicamente relevantes.