Concomitant Treatment with Doxycycline and Rifampicin in Balb/c Mice Infected with Brucella abortus 2308 Fails to Reduce Inflammation and Motor Disability.

Brucellosis is an infection widely distributed around the world, and in some countries it is considered a public health problem. Brucellosis causes insidious symptoms that make it difficult to diagnose. Infection can also trigger chronic pain and neuropsychiatric complications. Antibiotics are not always effective to eradicate infection, contributing to chronicity. We aimed to investigate the effects of antibiotic treatment on proinflammatory cytokines, neurotransmitters, corticosterone, and behavior in a murine model of infecrion of B. abortus strain 2308. Four study groups were created: (a) control; (b) antibiotic control; (c) infected with B. abortus 2308; and (d) infected and treated with rifampicin and doxycycline. We determined B. abortus 2308 colony-forming units (CFUs), the count of dendritic cells, and macrophages in the spleen; serum levels of cytokines and corticosterone; levels of serotonin, dopamine, epinephrine, and norepinephrine in the brain; and equilibrium, physical strength, anxiety, and hopelessness tests. The infected and treated mice group was compared with the control and infected mice to assess whether treatment is sufficient to recover neuroimmunoendocrine parameters. Our results showed that despite the treatment of brucellosis with rifampicin and doxycycline, antibiotic-treated mice showed a persistence of B. abortus 2308 CFUs, an increased count in macrophage number, and higher circulating levels of corticosterone. Furthermore, the levels of IL-12, IL-6, and TNF-α remained higher. We found a decrease in muscular strength and equilibrium concomitant to changes in neurotransmitters in the hippocampus, cerebellum, and frontal cortex. Our data suggest that the remaining bacterial load after antibiotic administration favors inflammatory, neurochemical, and behavioral alterations, partly explaining the widespread and paradoxical symptomatology experienced by patients with chronic brucellosis.

Olfaction and Melatonin: The Use of the Olfactory Discrimination Test.

In order to investigate the role of melatonin in olfactory function, we present the olfactory discrimination test as a simple and low-cost behavioral assessment. The test consists in evaluating the time that each rat spent in two compartments: one has a familiar odor (sawdust with the smell from the animal) and the other one with an unfamiliar odor (clean sawdust). Animals with the normal olfactory functions will discriminate between these two odors and will spend more time in the familiar compartment. We used the olfactory discrimination test to evaluate the role of melatonin receptors expressed in the olfactory bulb of rats. In a previous study, our results have successfully detected an olfactory modulation, by mean of the olfactory discrimination test, promoted by the infusion of melatonin receptor ligands into the olfactory bulb of rats.

Intrapallidal injection of cannabidiol or a selective GPR55 antagonist decreases motor asymmetry and improves fine motor skills in hemiparkinsonian rats.

Cannabidiol (CBD) presents antiparkinsonian properties and neuromodulatory effects, possibly due to the pleiotropic activity caused at multiple molecular targets. Recently, the GPR55 receptor has emerged as a molecular target of CBD. Interestingly, GPR55 mRNA is expressed in the external globus pallidus (GPe) and striatum, hence, it has been suggested that its activity is linked to motor dysfunction in Parkinson's disease (PD). The present study aimed to evaluate the effect of the intrapallidal injection of both CBD and a selective GPR55 antagonist (CID16020046) on motor asymmetry, fine motor skills, and GAD-67 expression in hemiparkinsonian rats. The hemiparkinsonian animal model applied involved the induction of a lesion in male Wistar rats via the infusion of the neurotoxin 6-hydroxydopamine (6-OHDA) into the medial forebrain bundle via stereotaxic surgery. After a period of twenty days, a second surgical procedure was performed to implant a guide cannula into the GPe. Seven days later, lysophosphatidylinositol (LPI), CBD, or CID16020046 were injected once a day for three consecutive days (from the 28th to the 30th day post-lesion). Amphetamine-induced turning behavior was evaluated on the 14th and 30th days post-injury. The staircase test and fine motor skills were evaluated as follows: the rats were subject to a ten-day training period prior to the 6-OHDA injury; from the 15th to the 19th days post-lesion, the motor skills alterations were evaluated under basal conditions; and, from the 28th to the 30th day post-lesion, the pharmacological effects of the drugs administered were evaluated. The results obtained show that the administration of LPI or CBD generated lower levels of motor asymmetry in the turning behavior of hemiparkinsonian rats. It was also found that the injection of CBD or CID16020046, but not LPI, in the hemiparkinsonian rats generated significantly superior performance in the staircase test, in terms of the use of the forelimb contralateral to the 6-OHDA-induced lesion, when evaluated from the 28th to the 30th day post-lesion. Similar results were also observed for superior fine motor skills performance for pronation, grasp, and supination. Finally, the immunoreactivity levels were found to decrease for the GAD-67 enzyme in the striatum and the ipsilateral GPe of the rats injected with CBD and CID16020046, in contrast with those lesioned with 6-OHDA. The results obtained suggest that the inhibitory effects of CBD and CID16020046 on GPR55 in the GPe could be related to GABAergic overactivation in hemiparkinsonism, thus opening new perspectives to explain, at a cellular level, the reversal of the motor impairment observed in PD models.

Effect of Cell Therapy and Exercise Training in a Stroke Model, Considering the Cell Track by Molecular Image and Behavioral Analysis.

The goal of this study is to see how combining physical activity with cell treatment impacts functional recovery in a stroke model. Molecular imaging and multimodal nanoparticles assisted in cell tracking and longitudinal monitoring (MNP). The viability of mesenchymal stem cell (MSC) was determined using a 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl tetrazolium bromide (MTT) assay and bioluminescent image (BLI) after lentiviral transduction and MNP labeling. At random, the animals were divided into 5 groups (control-G1, and experimental G2-G5). The photothrombotic stroke induction was confirmed by local blood perfusion reduction and Triphenyltetrazolium chloride (TTC), and MSC in the G3 and G5 groups were implanted after 24 h, with BLI and near-infrared fluorescence image (NIRF) tracking these cells at 28 h, 2, 7, 14, and 28 days. During a 28-day period, the G5 also conducted physical training, whereas the G4 simply did the training. At 0, 7, 14, and 28 days, the animals were functionally tested using a cylinder test and a spontaneous motor activity test. MNP internalization in MSC was confirmed using brightfield and fluorescence microscopy. In relation to G1 group, only 3% of cell viability reduced. The G2-G5 groups showed more than 69% of blood perfusion reduction. The G5 group performed better over time, with a progressive recovery of symmetry and an increase of fast vertical movements. Up to 7 days, BLI and NIRF followed MSC at the damaged site, demonstrating a signal rise that could be connected to cell proliferation at the injury site during the acute phase of stroke. Local MSC therapy mixed with physical activity resulted in better results in alleviating motor dysfunction, particularly during the acute period. When it comes to neurorehabilitation, this alternative therapy could be a suitable fit.

Lower antidepressant response to fluoxetine is associated with anxiety-like behavior, hippocampal oxidative imbalance, and increase on peripheral IL-17 and IFN-γ levels.

Major depression is a leading contributor to the global burden of disease. This is mainly related to the disorder chronic and recurrent nature, and to high rates of refractoriness to treatment. Limited efficacy with currently available antidepressants highlights the need for more effective options for treating drug-resistant patients and emphasizes the importance of developing specific preclinical models for treatment-resistant populations. Treatment-resistant depression (TRD) is commonly defined as failure to respond to two or more trials of antidepressants. In this study, we investigated the effect of fluoxetine treatment for fourteen days on the depressive-like behavior and the oxidative and inflammatory parameters of mice submitted to chronic corticosterone administration. After 21 days of subcutaneous corticosterone administration (20 mg/kg/day) and 14 days of oral fluoxetine treatment (10 mg/kg/day, started on day 7 of induction protocol), we separated animals into two groups according to the tail suspension test (TST) results: antidepressant responders (good response to antidepressant, GRA) and non-responders (resistance to antidepressant, AR). Forced swimming test (FST), elevated plus maze test (EPMT), and open field test (OFT) were performed. We found that animals classified as AR (i.e., those with higher immobility values in the TST) demonstrated anxiety-like behavior in the EPMT, increased H2O2 levels, and decreased catalase activity in the hippocampus, as well as increased serum levels of IL-17 and IFN-γ. Our findings suggest that a redox imbalance in the hippocampus, combined with increased levels of peripheral IL-17 and INF-γ, may be involved with an impaired response to fluoxetine.

Effects of thymoquinone in a rat model of reserpine-induced depression

The objective of this study is to examine the antidepressant and antioxidant effects of thymoquinone (TQ) on reserpine-induced depression, and to investigate the antidepressant and antioxidant activity of combined treatment of TQ+citalopram. In total, 36 male Wistar rats were randomly divided into 6 groups: 1)control1, 2)control2, 3)reserpine, 4)reserpine+TQ 5)reserpine+citalopram and 6)reserpine+TQ+citalopram. Depression was induced by administering intraperitoneal reserpine of 0.2mg/kg/14days. For antidepressant effects, 10 mg/kg TQ and/or 10 mg/kg citalopram was administered intragastrically 30 minutes prior to the administration of reserpine. Rat behavior was examined using the Behavioral Test following the completion of treatment protocol. Total nitric oxide (NOx) levels, malondialdehyde (MDA) levels, total oxidants status (TOS), total antioxidant status (TAS) in brain cortex, plasma as well as brain cortex glutathione (GSH) and levels of plasma total sulfhydryl groups (RSH) were examined. Treatment with TQ ameliorated the reserpine-induced changes in the Behavioral Test (p<0.05). TQ treatment significantly increased dopamine (DA) and noradrenaline (NA) expressions when compared to the R group (p<0.01). Serotonin (5-HT) expression also increased significantly (p<0.05). Brain cortex and plasma TOS, MDA and NOx levels decreased, whereas TAS, GSH and RSH levels increased (p< 0.05). TQ has the ability to prevent depression induced by reserpine. The combination of TQ+citalopram can be used in the treatment of depression with a stronger antioxidant effect

Neurobehavioral evaluation and phytochemical characterization of a series of argentine valerian species.

Folkloric or galenic preparations of valerian roots and rhizomes have been used as sedatives/anxiolytics and sleep inducers since ancient times. "Valerianas" are plants that naturally grow in our region. Although some of them are used in folk medicine, they lack scientific information. We performed a comparative study of the phytochemical composition and the potential in vivo effects of ethanolic extracts of argentine valerian species: Valeriana carnosa Sm., V. clarionifolia Phil. and V. macrorhiza Poepp. ex DC., from "Patagonia Argentina"; V. ferax (Griseb.) Höck and V. effusa Griseb., from the central part of our country, and V. officinalis (as the reference plant). All these plants were rich in phenolic compounds, evidenced the presence of ligands for the benzodiazepine binding site of the GABAA receptor and were able to induce sedation as assessed by loss-of-righting reflex assays (500 mg/kg, i.p.). Mice treated with V. macrorhiza, V. carnosa and V. ferax extracts showed reduced exploratory behaviors while V. clarionifolia produced anxiolytic-like activities (500 mg/kg, i.p.) in the Hole board test. Oral administrations (300 mg/kg and 600 mg/kg, p.o.) evidenced sedative effects for V. ferax and anxiolytic-like properties for V. macrorhiza, V. carnosa and V. clarionifolia extracts. Our native valerian species are active on the CNS, validating its folkloric use as anxiolytic/sedative and sleep enhancers.

RMD86, a thiophene derivative, promotes antinociceptive and antipyretic activities in mice.

Treatment of pain and fever remains an important challenge for modern medicine. Non-steroidal anti-inflammatory drugs (NSAIDs) are the pharmacological options most often used, but their frequent use exposes the patient to serious side effects and dangerous drug interactions. In this context, thiophene derivatives are promising therapeutic alternatives. In this study, we evaluated the in vivo and in silico antinociceptive and antipyretic properties of RMD86, a thiophene derivative. At 100 mg/kg, RMD86 induced no significant changes in the motor coordination of mice in the Rotarod test. At 25, 50, and 100 mg/kg RMD86 significantly reduced the number of abdominal contortions induced by acetic acid (antinociceptive activity) in mice when compared to the control. In the formalin test, for the first phase, there was a reduction in licking times at doses of 50 and 100 mg/kg. In the second phase, reduction occurred at all doses. In the hot plate test, RMD86 (at 100 mg/kg) increased latency time in the first 30 min. For antipyretic activity, RMD86, when compared to the reference drug acetaminophen (250 mg/kg), significantly reduced pyrexia at 30, 60, and 120 min, at dosages of 25, 50 and 100 mg/kg. Molecular docking studies revealed that RMD86 presents a greater number of interactions and lower energy values than both the co-crystallized ligand and the reference drug (meloxicam) against COX-1 and COX-2 isoenzymes. The results give evidence of the analgesic and antipyretic properties like NSAIDs suggesting its potential for pain therapy.

Garlic passion fruit (Passiflora tenuifila Killip): Assessment of eventual acute toxicity, anxiolytic, sedative, and anticonvulsant effects using in vivo assays.

Several Passiflora species are known for their sedative and anxiolytic properties. However, the functional properties of Passiflora tenuifila Killip are still unexplored. The objective of this work was to evaluate the phenolic composition and acute toxicity, anxiolytic, sedative, and anticonvulsant effects using in vivo assays. The whole fruit (peel, pulp, and seed) was lyophilized and used for all assays. LC-MS showed 19 phenolic compounds, tentatively identified as flavonoids and phenolic acids. Acute treatment with single doses of up to 2000 mg kg-1 in Wistar rats showed no signs of mortality or toxicity over 14 days. The assay of functional effects was performed with Swiss mice, four groups, received by gavage, doses of P. tenuifila (200 or 400 mg kg-1 body weight), water, and diazepam (as negative and positive control), and behavior tests were performed after 60 min of the treatments. The animals treated with P. tenuifila fruit showed a significant decrease in locomotor activity, indicating a sedative and anxiolytic activity. No significant changes were observed in the rotarod apparatus, suggesting that the P. tenuifila fruit did not cause muscle relaxation. The 400 mg kg-1 dose of P. tenuifila exerted a protective effect against pentylenetetrazole-induced seizures, decreasing the severity and not causing the death of the animals. In conclusion, P. tenuifila showed no acute toxicity and had a promising effect as an anxiolytic agent, hypnotic-sedative and anticonvulsant, which could be related to its composition of flavonoids and phenolic acids.

A non-reflexive method based on the variability of temperature and bioimpedance in measuring inflammatory hyperalgesia and analgesia in mice.

BACKGROUND: Preclinical studies measure withdrawal responses to evoking thermal and mechanical stimuli instead of the more clinically important spontaneous pain. NEW METHOD: Therefore, we studied the effect of peripheral inflammation induced by intraplantar administration of complete Freund's adjuvant (CFA) in mice on the variability of temperature and bioimpedance as an index of pain produced by inflammation. To this end, we initially determined mathematical scores based on changes in temperature and bioimpedance (STB) for animals with an inflamed paw and compared these scores with commonly used measures of inflammatory pain. We then pharmacologically validated the tool using dexamethasone. RESULTS: The STB analysis resembled the response found in the von Frey Hair (vFH) test. The CFA-induced increase in STB and vFH tests were reversed by intraperitoneal administration of dexamethasone. The correlation between the STB and vFH measurements showed a high correlation coefficient (R2 = 0.911, p < 0.001). COMPARISON WITH EXISTING METHOD: Our results also demonstrated that CFA paw injection induced mechanical hyperalgesia in mice and remained virtually unaltered during all time-points tested for 5 days, as measured with vFHs. The administration of CFA into the paw induced a large increase in paw volume that was apparent 1 and 5 days after the injection. The CFA injection resulted in a significant (p < 0.05) decrease in the response latency to the heat stimulus, as evaluated on day 4 post-CFA injection. CONCLUSIONS: The data presented here suggest that STB may provide a novel non-invasive approach for inflammatory pain detection.

Monoamine Involvement in the Antidepressant-Like Effect of ß-Caryophyllene.

BACKGROUND: Major depressive disorder is a psychiatric disorder that affects 4.4% of the population worldwide. Although the majority of antidepressant drugs ameliorate depressive symptoms, there is still a need for safer and more effective antidepressant. OBJECTIVE: Evaluate the antidepressant-like activity of sesquiterpene compound ß-caryophyllene (BCP) for the possible contribution of the monoamine and hippocampal levels of brain-derived neurotrophic factor (BDNF). METHODS: Male albino Swiss mice were subjected to the forced swimming test after acute treatment and to the tail suspension test after repeated treatment. Hippocampal levels of BDNF were assayed by enzyme-linked immunosorbent assay. RESULTS: The anti-immobility effect of BCP was reverted by pretreatment with an inhibitor of catecholamine synthesis α-methyl-p-tyrosine (100 mg/kg, i.p.), α2-adrenergic antagonist yohimbine (1 mg/kg, i.p.), and ß-adrenergic antagonist propranolol (2 mg/kg, i.p.), but not by pretreatment with either α1-adrenergic antagonist prazosin (1 mg/kg, i.p.) or 5-HT1A antagonist NAN-190 (0.5 mg/kg, i.p.), thereby suggesting the involvement of α2 and ß-adrenergic receptors, but not of the α1-adrenergic and 5-HT1A serotonergic receptors, in BCP's antidepressive-like activity. Furthermore, BCP increased BDNF levels in the hippocampus after 14 days of treatment. No treatments in this study altered locomotor activity in the open field test. CONCLUSION: This study provides a new mechanism of BCP-induced antidepressant-like effect mediated by some sub-types of catecholaminergic neurotransmitter system that could be a candidate for clinical tests of new treatments for depressive disorders.

Individual and sex differences in high and low responder phenotypes.

Individual differences in responses to a novel environment are an important tool to predict predisposition to neuropsychiatric disorders. One way to examine individual differences involves classifying animals based on locomotion in a novel context. In this study we focused on individual and sex differences by categorizing female and male mice as high (HR) or low responders (LR) on the basis of open field locomotion. We then assessed whether groups differed on behavioral measures of spontaneous alternations, anxiety, depression and contextual fear conditioning. In the Y-maze, we observed no differences across HR/LR or sex on spontaneous alternations, but HR displayed more locomotion. HR male mice showed less anxiety-like behavior in the light-dark test but not the elevated plus maze. We observed no differences in the forced swim test across HR/LR, although males exhibited greater depression-like behavior overall. HR mice exhibited less contextual fear memory compared to LR regardless of sex. Principal component analyses suggested sex-specific patterns of behaviors across tests, with female responses within individual tests tending to load together. In females anxiety- and depression-like behaviors explained a large part of the variance observed across tests in our battery, whereas male behavior was primarily explained by variables related to locomotion.

Antidepressant, antioxidant and neurotrophic properties of the standardized extract of Cocos nucifera husk fiber in mice.

The plant Cocos nucifera and its derivatives have shown antidepressant-like effects, although its hydroalcoholic extract has not been studied with this end in mind. Therefore, we decided to determine the antidepressant-like effects of the standardized hydroalcoholic extract of Cocos nucifera husk fiber (HECN) as well as oxidative alterations in the prefrontal cortex (PFC), hippocampus (HC) and striatum (ST), and the levels of brain-derived neurotrophic factor (BDNF) in the HC of mice. The extract was characterized based on the content of total polyphenols as well as two phenol compounds-catechin and chlorogenic acid-by HPLC-PDA. Male animals were treated per os (p.o.) for 7 days with distilled water or HECN (50, 100 or 200 mg/kg), or intraperitoneally with vitamin E (Vit E 400 mg/kg). One hour after the last drug administration, the animals were submitted to the open field test, forced swimming test (FST), tail suspension test (TST) and, immediately after the behavioral tests, had their brain removed for neurochemical determinations. The results showed that HECN100 decreased the immobility time in the FST and TST presenting, thus demonstrating an antidepressant-like effect. The administration of HECN decreased malondialdehyde levels in all doses and brain areas studied with the exception of HECN50 in the HC. The administration of HECN also decreased nitrite levels in all doses and brain regions studied. HECN100 also increased the levels of BDNF in HC of mice. In conclusion, we demonstrated that HECN has antidepressant-like properties, probably based on its antioxidant and neurotrophic effects, and is thus relevant for the treatment of depression.

Diferencias individuales en los perros domésticos (Canis familiaris): Revisión de las evaluaciones conductuales / Individual differences in domestic dogs (Canis familiaris): A behavioral assessment review

El estudio de las diferencias individuales en el comportamiento de los perros domésticos tiene un gran valor aplicado dado que permite una mejor selección de los mismos para cumplir las variadas funciones que tienen en la sociedad humana como perros guía, policía, compañía, rescatistas de personas, etc. En el trabajo que se informa se presenta una revisión de estudios sobre diferencias individuales en perros, basada únicamente en las baterías conductuales que evalúan un conjunto de rasgos del temperamento. Con este objetivo se realiza una breve descripción de cada batería de pruebas utilizadas en la literatura, analizando las definiciones operacionales de las variables evaluadas y los diferentes tipos de estímulos utilizados. Los rasgos mayormente evaluados son: temerosidad, agresividad, disposición al entrenamiento y sociabilidad. La temerosidad, en general es evaluada a través de la respuesta del animal ante la aparición de un estímulo súbito que puede ser intenso o no, como por ejemplo la reacción frente a un ruido fuerte, la apertura de un paraguas, o la aparición repentina de una figura humana. La agresividad se mide a través de la reacción frente a la amenaza o provocación por parte de un humano, la sustracción de un objeto o la confrontación con un perro dominante. La disposición al entrenamiento es estudiada a través de la respuesta del animal frente a diferentes estímulos como el juego con un trapo o una cuerda, el ejercicio de devolución de un objeto o la obediencia frente a distintos comandos. Por último, la sociabilidad se evalúa con la aparición o el acercamiento de un humano desconocido o con la exposición a un perro no familiar. Se discuten además las limitaciones metodológicas de las baterías así como también los importantes usos aplicados de las mismas.

A review of the research on individual differences in domestic dogs is presented in this paper. Temperament has been defined as the group of individual differences in behavior which is manifested steadily across situations and over time. It has been studied in a wide range of species including humans. Domestic dogs have undergone intense processes of selection on behavioral traits during domestication, and in the development of different breeds. These processes produced a great morphological, genetic and behavioral variability, which turned the dog in an interesting model for the study of individual differences. In this study we present a review of the different test batteries developed for the assessment of various behavioral traits. Test batteries are defined as standard experimental situations where a stimulus is used to provoke a behavior which is compared statistically to that of other individuals in the same situations, in order to classify the subjects. To achieve this aim, a brief description of seven batteries is given. Four of them evaluated dogs from breeding or train ing centers. Their aim was to select those animals which possess the most adequate traits to become guide or police dogs. The remaining batteries evaluated shelter dogs in order to elaborate a behavioral profile to improve the adoption process. In each battery described we analysed the operational definitions of the variables, the method used for scoring the animal's responses (overall vs. direct), the use of trained observers and the different types of stimuli used. The behavioral traits that are mainly assessed in dogs are fearfulness, aggressiveness, responsiveness to training, and sociability. Fearfulness is generally assessed through the appearance of a startling stimulus, which can be intense or not, such as the reaction towards a strong noise, the open ing of an umbrella, or the sudden appearance of a human figure. Aggressiveness is measured through the reaction towards a threat or provocation of a human being, the removal of an object, or the confrontation with a dominant dog. Responsiveness to train ing is studied through the response of the animal towards different stimuli, such as tug of war, retrieval, or obedience to commands. Finally, sociability is assessed with the appearance or approach of an unknown human being, or with the exposure to an unfamiliar dog. On the whole, the relevance of the assessment of these traits is fundamentally linked to the close relationship between dogs and humans. On the other hand, from a methodological point of view, it is important to note that most of the batteries evaluated a great number of subjects, which is difficult to achieve. Also, they allow to study behavioral variability in several traits at the same time, providing a large amount of information. Notably, several tests obtained predictive validity. The main difficulties presented by the temperament batteries are the diversity in nomenclature of the same traits and the variety of definitions used. Some of them even lack the reliability and validity requirements which are necessary to be considered measuring instruments. Furthermore, complex statistical analyses are done with unreliably obtained data. To conclude, despite the methodological limitations, temperament batteries have a great applied value. They allow the adequate selection of animals before the investment of valuable resources in their training, and a correct temperament evaluation can improve the adoption process of shelter dogs, diminishing the risk of relinquishment by predicting behavioral problems. The scope of this subject does not only matter to researchers interested in animal models of individual differences in behavior, but also to all the professionals who work in applied areas where dogs are an elemental part of the task, as the rescue or search of missing people, assisted therapy, drug detection, herding, etc.