Brain Of Adult Male Rats Research Articles

The Effects of Short-Term Stress and Long-Term Fluoxetine Treatment on the Expression of Apoptotic Proteins in the Brain

The effects of 2- or 8-week-long daily treatment with fluoxetine at a dose of 7.26–7.70 mg/kg given with drinking water and short-term forced-swim stress on the levels of mRNAs of anti- and pro-apoptotic proteins, that is, Bcl-xL and Bax, respectively, were studied in the brains of adult male rats using the RT-PCR method. Antiapoptotic effects of stress on the expression of these proteins were observed in the hippocampus of rats that were not treated with fluoxetine and in the midbrain after 2 weeks of the antidepressant treatment. Pro-apoptotic effects of stress were revealed in the frontal cortex of animals that were not treated with fluoxetine and after 2 weeks of fluoxetine treatment. An 8-week-long fluoxetine treatment resulted in an increase in the basal Bax expression in the hippocampus and in anti-apoptotic effects in the neocortex, which were more clearly seen after stress. The observed interaction of the effects of stress and fluoxetine on the expression of proteins of neuronal survival and plasticity may provide anti- or proapoptotic action of the antidepressant on the cells of the emotiogenic structures of the brain.

ALDEHYDE DEHYDROGENASE 1L1 IN RAT BRAIN CELLS

Aldehyde dehydrogenase belonging to family 1, member L1 (Aldh1L1) is one of the most important enzymes called astrocytes that determine such important functions of these cells as participation in folate metabolism and inactivation of formiate in the CNS. The aim of this study was immunocytochemical detection of cells synthetizing Aldh1L1 in rat brain, and determination of their topography and morphology features. The brain of adult male Wistar rats (n=10) was used at the work. The material was fixed in zinc-ethanol-formaldehyde, a special fixative providing high preservation of antigenic determinants. It was shown that A ldh1L1 is detected in all brain anatomic structures. Among brain cells expressing Aldh1L1 macroglia cells - astrocytes and ep-endymocytes - were identified. In astrocytes the most intensive immunohistochemical reaction was observed in the endfeets of processes of these cells and in superficial astrocytes forming the superficial glial border membrane. In ependymocytes, the product of immune reaction was detected in the cytoplasm as numerous granules of various shapes and size (from 0.1x0.2 to 1.3X3.7 pm). The predominant localization of Aldh1L1 in brain cells involved in transport of substances through blood-brain, CSF-brain, and CSF-blood barriers allows one to expect that this protein will prove to be useful functional marker during experimental investigations of the CNS barrier system and evaluating the reaction of brain to toxic metabolic products of alcohol surrogates.

Nestin expression and invivo proliferative potential of tanycytes and ependymal cells lining the walls of the third ventricle in the adult rat brain.

There is a disagreement in the literature concerning the degree of proliferation of cells in the walls of the third ventricle (3rdV) under normal conditions in the adult mammalian brain. To address this issue, we mapped the cells expressing the neural stem/progenitor cell marker nestin along the entire rostrocaudal extent of the 3rdV in adult male rats and observed a complex distribution. Abundant nestin was present in tanycyte cell bodies and processes and also was observed in patches of ependymal cells as well as in isolated ependymal cells throughout the walls of the 3rdV. However, we observed very limited ependymal cell or tanycyte proliferation in normal adult rats as determined by bromodeoxyuridine (BrdU) incorporation or the expression of Ki-67. Moreover, fewer than 13% of the cells that were BrdU-positive (BrdU+) or Ki-67-positive (Ki-67+) expressed nestin. These observations stand in contrast to those made in the subventricular zone of the lateral ventricle (SVZ) and subgranular zone of the hippocampal formation (SGZ), where cell proliferation measured by BrdU incorporation or Ki-67 expression is observed frequently in cells that also express nestin. Thus, while ependymal cell or tanycyte cell proliferation can be promoted by the addition of mitogens, dietary modifications or other invivo manipulations, the proliferation of ependymal cells and tanycytes in the walls of the 3rdV is very limited in the normal adult male rat brain.

Study the effect of chlorpyrifos pesticide on genomic DNA in tissues (liver, kidney and brain) in adult male rats

Study the effect of chlorpyrifos pesticide on genomic DNA in tissues (liver, kidney and brain) in adult male rats

Differential effects of the 18-kDa translocator protein (TSPO) ligand etifoxine on steroidogenesis in rat brain, plasma and steroidogenic glands: Pharmacodynamic studies

Etifoxine is indicated in humans for treating anxiety. In rodents, besides its anxiolytic-like properties, it has recently shown neuroprotective and neuroregenerative activities. It acts by enhancing GABAA receptor function and by stimulating acute steroid biosynthesis via the activation of the 18-kDa translocator protein. However, the regulatory action of etifoxine on steroid production is not well characterized. In this work, we performed dose-response, acute and chronic time-course experiments on the effects of intraperitoneal injections of etifoxine on steroid levels in adult male rat brain and plasma analyzed by gas chromatography-mass spectrometry. Concentrations of pregnenolone, progesterone and its 5α-reduced metabolites were significantly increased in both tissues in response to 25 and 50mg/kg of etifoxine, as compared with vehicle controls, and reached maximal values at 0.5–1h post-injection. Daily injections of etifoxine (50mg/kg, 15days) kept them increased at day 15. Comparisons between steroidogenic tissues revealed that 1h after 50mg/kg of etifoxine treatment, levels of pregnenolone, progesterone and corticosterone were highest in adrenal glands and markedly increased together with their reduced metabolites. They were also increased by etifoxine in brain and plasma, but not in testis except for corticosterone and its metabolites. In contrast, testosterone level was significantly decreased in testis while with its 5α-reduced metabolites, it was unchanged in brain. Results demonstrate that the modulation of steroid concentrations by etifoxine is dependent on the type of steroid and on the steroidogenic organ. They further suggest that adrenal steroids upregulated by etifoxine make an important contribution to the steroids present in brain. This work provides a precise and complete view of steroids regulated by etifoxine that could be useful in therapeutic research.

Dynamic glucocorticoid-dependent regulation of Sgk1 expression in oligodendrocytes of adult male rat brain by acute stress and time of day.

Recent studies support plasticity in adult brain white matter structure and myelination in response to various experiential factors. One possible contributor to this plasticity may be activity-dependent modulation of serum- and glucocorticoid-inducible kinase 1 (Sgk1) expression in oligodendrocytes. We examined whether Sgk1 expression in adult rat brain white matter is increased by acute stress-induced elevations in endogenous corticosterone and whether it fluctuates with diurnal variations in corticosterone. We observed rapid increases (within 30 min) in Sgk1 mRNA in the corpus callosum in response to acute stress, as well as large increases at the beginning of the rat’s active period (the time of peak corticosterone secretion). These increases were absent in adrenalectomized rats. Corticosterone treatment of adrenalectomized rats also rapidly increased corpus callosum Sgk1 mRNA. The majority of Sgk1 mRNA in corpus callosum was co-localized with myelin basic protein mRNA, suggesting that mature oligodendrocytes respond dynamically to acute stress and circadian rhythms. The regulation of Sgk1 expression by acute stress and time of day was selective for white matter, with limited alteration of Sgk1 expression by these factors in hippocampus and somatosensory cortex. These results indicate a unique sensitivity of oligodendrocyte Sgk1 expression to activity-dependent fluctuations in corticosterone hormone secretion, and raises the prospect that hypothalamic-pituitary-adrenal axis dysregulation or glucocorticoid pharmacotherapy may compromise the normal activity-dependent interactions between oligodendrocytes and neurons.

Effects of Tramadol Addiction on Brain of Adult Male Albino Rats and Role of lofexidine during Withdrawal Period: A Biochemical, Histopathological and Immunohistochemical Study

Background: Tramadol is a synthetic opioid analgesic commonly prescribed for moderate to severe pain, becoming abused more popular among teens in most countries. In addition to the euphoric and mood-enhancing effects sought by tramadol abusers, taking this drug for nonmedical purposes, abusing tramadol can lead to tolerance and dependence. Abusers who continue to take tramadol long enough and at high enough doses will eventually develop a physical dependence on the drug and experience unpleasant, or even dangerous, symptoms of withdrawal if they stop taking the medication. Objective: To study the biochemical, histopathological and immunohistochemical changes of repeated administration of tramadol on the brain cells of male albino rats and role of duration of addiction in the damaging effects produced, and to prove if there is a role for lofexidine in the treatment of tramadol addiction in withdrawal period and detect the changes after recovery period and withdrawal of tramadol .Materials and methods: 100 adult male albino rats were randomly divided into equal 5groups: Group I: (20 rats) Control group: including those given normal feeding. Group II: (20 rats) Tramadol treated group for one month. Group III: (20 rats) Tramadol treated group for 2 months. Group IV: (20 rats) Tramadol treated for one month then given lofexidine for another month during withdrawal. Group V: (20 rats) Tramadol treated for one month and left for another month for recovery. Animals were observed for any behavioral changes throughout the research and recorded. At the end of the experiment animals were scarified by cervical dislocation under inhalation anesthesia, autopsy was done and the brain specimens were obtained, prepared for biochemical study for dopamine level and others preserved for histopathological and immunohistochemical study with their specific procedures. Results: Repeated Tramadol administration resulted in rats behavioral changes( restlessness, irritability defensive aggressive reactions) and produced decreased dopamine levels and significant brain damage in the histopathological and immunohistochemical study that increased with increased period of intake (The maximum damage was recorded in group III with two months tramadol administration, varying degrees of recovery after stoppage of intake were noted in Group V and more improvement by Lofexidine treatment in Group IV). Conclusions: Repeated Tramadol administration causes degenerative changes on the rat brain which increased with increasing the period of this administration. Some improvement was detected after stoppage and more improvement with Lofexidine treatment in withdrawal period.

STUDY OF CHRONIC TOXIC EFFECT OF DELTAMETHRIN AND DIMETHOATE ON BRAIN OF ADULT MALE ALBINO RATS

organophosphate pesticides are being increasingly used in combination with Pyrethroids. The effects of single molecules are being studied, but the risk associated with pesticide mixtures is still to estimate. So, the purpose of the current study was to evaluate the individual and combined toxic effects of deltamethrin (DLM) and dimethoate (DM) on brain of adult male albino rats. For this purpose, 60 adult male albino rats were randomized into 5equal groups: Group I: negative control, Group II: positive control received 1ml corn oil once daily. Group III received deltamethrin (5 mg/kg b.w./orally ∕daily), Group IV received dimethoate (20 mg/kg b.w./ orally ∕daily), Group V received deltamethrin (5 mg/kg b.w) and dimethoate(20 mg/kg b.w)orally ∕daily . At the end of the study (12 weeks); Body weight was evaluated then blood sample were obtained for estimation of oxidative stress markers malondialdehyde (MDA) glutathione (GSH), total antioxidant capacity TAC) and plasma cholinesterase (PCHE) level then rats were sacrificed. The brains were excised, prepared for histopathological, immunohistochemical examination and DNA damage estimation by comet assay. Results revealed that single DLM and DM exposure significantly had adverse effects on adult male Albino rats in the form of decrease in the body weight, increase in brain &serum MDA, decrease in TAC &GSH and decrease in PCHE level. Pathological changes in brain of rats included, pychnosis, neuronal degeneration, neuropil vacuolization, hemorrhage and congested blood vessels beside positive immuoreaction for bax. Also they caused DNA damage compared to control group. In conclusion, chronic exposure to DLM and DM singly and in combination induced significant oxidative damage in rat brain, associated with marked perturbations in antioxidant defense system in addition to genotoxicity detected by comet assay. Also, the mixture of the two pesticides caused greater damage on the brain of male albino rats, than the individual pesticides.

A Role of Central NELL2 in the Regulation of Feeding Behavior in Rats.

A brain-enriched secreting signal peptide, NELL2, has been suggested to play multiple roles in the development, survival, and activity of neurons in mammal. We investigated here a possible involvement of central NELL2 in regulating feeding behavior and metabolism. In situ hybridization and an im-munohistochemical approach were used to determine expression of NELL2 as well as its colocalization with proopiomelanocortin (POMC) and neuropeptide Y (NPY) in the rat hypothalamus. To investigate the effect of NELL2 on feeding behavior, 2 nmole of antisense NELL2 oligodeoxynucleotide was administered into the lateral ventricle of adult male rat brains for 6 consecutive days, and changes in daily body weight, food, and water intake were monitored. Metabolic state-dependent NELL2 expression in the hypothalamus was tested in vivo using a fasting model. NELL2 was noticeably expressed in the hypothalamic nuclei controlling feeding behavior. Furthermore, all arcuatic POMC and NPY positive neurons produced NELL2. The NELL2 gene expression in the hypothalamus was up-regulated by fasting. However, NELL2 did not affect POMC and NPY gene expression in the hypothalamus. A blockade of NELL2 production in the hypothalamus led to a reduction in daily food intake, followed by a loss in body weight without a change in daily water intake in normal diet condition. NELL2 did not affect short-term hunger dependent appetite behavior. Our data suggests that hypothalamic NELL2 is associated with appetite behavior, and thus central NELL2 could be a new therapeutic target for obesity.

TIMING OF TRAUMATIC BRAIN INJURY AND ITS SYSTEMIC EFFECTS ON THE LUNGS OF ADULT MALE ALBINO RATS

Objective: Timing of traumatic brain injury (TBI) is very common and important especially, in forensic autopsy cases with no signs of intracranial hemorrhage or contusion and with short time of survival following head injury. In such cases it is difficult to determine the cause of death. TBI results in systemic inflammatory responses that are complicated by dysfunction of peripheral organs such as the lungs, liver and intestine. The lung is especially critical in the setting of lung transplantation, where more than half of donor allografts are obtained postmortem from individuals with TBI. The aim of the present study was to assess post-intervals of traumatic brain injury and to evaluate the effects of TBI on lungs by measuring serum levels of High mobility group box 1 protein (HMGB1), performing quantitative real-time polymerase chain reaction (qPCR) analysis for gene expression and detecting any histopathological changes or immunohistochemical reaction of brain and lungs. Materials and Methods: Fifty four adult male albino rats divided into in to 3 groups (18 rats each): Group I: Negative control: rats left without any intervention. Group II: (sham): rats were anesthetized with ether inhalation and left without TBI inflection. Group III (TBI): rats were anesthetized with ether inhalation then the head was placed on platform and brain injury was done by weight drop method. After TBI infliction, six rats from group III (TBI) at each time point (1 st, 3rd& 7thday) and six rats from group I&II were anesthetized and blood samples were drawn for measuring serum level of (HMGB1).Then rats were sacrificed, specimens from contused cerebral cortex and lungs were subjected to quantitative real-time polymerase chain reaction (qPCR) analysis for gene expression of HMCB1, histopathology examination and immunohistochemical detection of HMGB1 immunoreaction. Results: Traumatic brain injury induced time dependent up-regulation of HMGB1 in serum and qPCR gene expression. Significant histopathological inflammatory changes and positive HMGB1 immunoreaction of brain and lung tissues of TBI (group III) were detected when compared with both control groups. Conclusion: It can be concluded that traumatic brain injury induced time dependent changes in serum and tissue levels of HMGB1, also histopathological changes in the brain and lungs of adult male albino rats. So, this marker can be useful for the diagnosis and timing of brain trauma and predict post TBI lung injury.

Neuroanatomical differences in FAST and SLOW rat strains with differential vulnerability to kindling and behavioral comorbidities.

The neurobiological factors underlying a predisposition towards developing epilepsy and its common behavioral comorbidities are poorly understood. FAST rats are a strain that has been selectively bred for enhanced vulnerability to kindling, while the SLOW strain has been bred to be resistant to kindling. FAST rats also exhibit behavioral traits reminiscent of those observed in neurodevelopmental disorders (autism spectrum disorder (ASD)/attention-deficit/hyperactivity disorder (ADHD)) commonly comorbid with epilepsy. In this study, we aimed to investigate neuroanatomical differences between these strains that may be associated with a differential vulnerability towards these interrelated disorders. Ex vivo high-resolution magnetic resonance imaging on adult male FAST and SLOW rat brains was performed to identify morphological differences in regions of interest between the two strains. Behavioral examination using open-field, water consumption, and restraint tests was also conducted on a subgroup of these rats to document their differential ASD/ADHD-like behavior phenotype. Using optical stereological methods, the volume of cerebellar granule, white matter, and molecular layer and number of Purkinje cells were compared in a separate cohort of adult FAST and SLOW rats. Behavioral testing demonstrated hyperactivity, impulsivity, and polydipsia in FAST versus SLOW rats, consistent with an ASD/ADHD-like phenotype. Magnetic resonance imaging analysis identified brain structural differences in FAST compared with SLOW rats, including increased volume of the cerebrum, corpus callosum, third ventricle, and posterior inferior cerebellum, while decreased volume of the anterior cerebellar vermis. Stereological measurements on histological slices indicated significantly larger white matter layer volume, reduced number of Purkinje cells, and smaller molecular layer volume in the cerebellum in FAST versus SLOW rats. These findings provide evidence of structural differences between the brains of FAST and SLOW rats that may be mechanistically related to their differential vulnerability to kindling and associated comorbid ASD/ADHD-like behaviors.

Sex differences in subcellular distribution of delta opioid receptors in the rat hippocampus in response to acute and chronic stress

Drug addiction requires associative learning processes that critically involve hippocampal circuits, including the opioid system. We recently found that acute and chronic stress, important regulators of addictive processes, affect hippocampal opioid levels and mu opioid receptor trafficking in a sexually dimorphic manner. Here, we examined whether acute and chronic stress similarly alters the levels and trafficking of hippocampal delta opioid receptors (DORs). Immediately after acute immobilization stress (AIS) or one-day after chronic immobilization stress (CIS), the brains of adult female and male rats were perfusion-fixed with aldehydes. The CA3b region and the dentate hilus of the dorsal hippocampus were quantitatively analyzed by light microscopy using DOR immunoperoxidase or dual label electron microscopy for DOR using silver intensified immunogold particles (SIG) and GABA using immunoperoxidase. At baseline, females compared to males had more DORs near the plasmalemma of pyramidal cell dendrites and about 3 times more DOR-labeled CA3 dendritic spines contacted by mossy fibers. In AIS females, near-plasmalemmal DOR-SIGs decreased in GABAergic hilar dendrites. However, in AIS males, near-plasmalemmal DOR-SIGs increased in CA3 pyramidal cell and hilar GABAergic dendrites and the percentage of CA3 dendritic spines contacted by mossy fibers increased to about half that seen in unstressed females. Conversely, after CIS, near-plasmalemmal DOR-SIGs increased in hilar GABA-labeled dendrites of females whereas in males plasmalemmal DOR-SIGs decreased in CA3 pyramidal cell dendrites and near-plasmalemmal DOR-SIGs decreased hilar GABA-labeled dendrites. As CIS in females, but not males, redistributed DOR-SIGs near the plasmalemmal of hilar GABAergic dendrites, a subsequent experiment examined the acute affect of oxycodone on the redistribution of DOR-SIGs in a separate cohort of CIS females. Plasmalemmal DOR-SIGs were significantly elevated on hilar interneuron dendrites one-hour after oxycodone (3 mg/kg, I.P.) administration compared to saline administration in CIS females. These data indicate that DORs redistribute within CA3 pyramidal cells and dentate hilar GABAergic interneurons in a sexually dimorphic manner that would promote activation and drug related learning in males after AIS and in females after CIS.

Oxidative stress in rat brain but not in liver following oral administration of a low dose of nanoparticulate silver

While it is known that silver nanoparticles (AgNPs) can enter the brain, our knowledge of AgNP-induced neurotoxicity remains incomplete. We investigated the ability of 10 nm citrate-stabilized AgNPs to generate oxidative stress in brain and liver of adult male Wistar rats after repeated oral exposure for 14 days, using a low dose of 0.2 mg/kg b.w. as compared with the same dose of ionic silver (silver citrate). In AgNP-exposed animals, the level of reactive oxygen species (ROS), lipid peroxidation (MDA) and glutathione peroxidase (GPx) activity were found to be significantly higher in brain relative to the control group receiving saline. Administration of ionic silver (silver citrate) increased ROS and MDA levels in both tissues. Activities of GPx in brain so as superoxide dismutase (SOD) and catalase (CAT) in liver of exposed animals were also elevated. Besides, AgNPs and silver ions were both found to cause statistically significant decrease in the reduced-to-oxidized glutathione ratio (GSH/GSSG) in brain. The results show that exposure to a very low dose of particulate silver generates mild oxidative stress in the brain but not in the liver of rats, indicating a role of oxidative stress in AgNP-induced neurotoxicity.

Age and sex differences in oxytocin and vasopressin V1a receptor binding densities in the rat brain: focus on the social decision-making network

Oxytocin (OT) and vasopressin (AVP) regulate various social behaviors via activation of the OT receptor (OTR) and the AVP V1a receptor (V1aR) in the brain. Social behavior often differs across development and between the sexes, yet our understanding of age and sex differences in brain OTR and V1aR binding remains incomplete. Here, we provide an extensive analysis of OTR and V1aR binding density throughout the brain in juvenile and adult male and female rats, with a focus on regions within the social decision-making network. OTR and V1aR binding density were higher in juveniles than in adults in regions associated with reward and socio-spatial memory and higher in adults than in juveniles in key regions of the social decision-making network and in cortical regions. We discuss possible implications of these shifts in OTR and V1aR binding density for the age-specific regulation of social behavior. Furthermore, sex differences in OTR and V1aR binding density were less numerous than age differences. The direction of these sex differences was region-specific for OTR but consistently higher in females than in males for V1aR. Finally, almost all sex differences in OTR and V1aR binding density were already present in juveniles and occurred in regions with denser binding in adults compared to juveniles. Possible implications of these sex differences for the sex-specific regulation of behavior, as well potential underlying mechanisms, are discussed. Overall, these findings provide an important framework for testing age- and sex-specific roles of OTR and V1aR in the regulation of social behavior.

Resistance to DNA Damaging Agents Produced Invasive Phenotype of Rat Glioma Cells-Characterization of a New in Vivo Model.

Chemoresistance and invasion properties are severe limitations to efficient glioma therapy. Therefore, development of glioma in vivo models that more accurately resemble the situation observed in patients emerges. Previously, we established RC6 rat glioma cell line resistant to DNA damaging agents including antiglioma approved therapies such as 3-bis(2-chloroethyl)-1-nitrosourea (BCNU) and temozolomide (TMZ). Herein, we evaluated the invasiveness of RC6 cells in vitro and in a new orthotopic animal model. For comparison, we used C6 cells from which RC6 cells originated. Differences in cell growth properties were assessed by real-time cell analyzer. Cells’ invasive potential in vitro was studied in fluorescently labeled gelatin and by formation of multicellular spheroids in hydrogel. For animal studies, fluorescently labeled cells were inoculated into adult male Wistar rat brains. Consecutive coronal and sagittal brain sections were analyzed 10 and 25 days post-inoculation, while rats’ behavior was recorded during three days in the open field test starting from 25th day post-inoculation. We demonstrated that development of chemoresistance induced invasive phenotype of RC6 cells with significant behavioral impediments implying usefulness of orthotopic RC6 glioma allograft in preclinical studies for the examination of new approaches to counteract both chemoresistance and invasion of glioma cells.

NADPH oxidase activity and reactive oxygen species production in brain and kidney of adult male hypertensive Ren-2 transgenic rats.

Hypothalamic paraventricular nucleus (PVN) and rostral ventrolateral medulla (RVLM) play an important role in brain control of blood pressure (BP). One of the important mechanisms involved in the pathogenesis of hypertension is the elevation of reactive oxygen species (ROS) production by nicotine adenine dinucleotide phosphate (NADPH) oxidase. The aim of our present study was to investigate NADPH oxidase-mediated superoxide (O(2)(-)) production and to search for the signs of lipid peroxidation in hypothalamus and medulla oblongata as well as in renal medulla and cortex of hypertensive male rats transgenic for the murine Ren-2 renin gene (Ren-2 TGR) and their age-matched normotensive controls - Hannover Sprague Dawley rats (HanSD). We found no difference in the activity of NADPH oxidase measured as a lucigenin-mediated O(2)(-) production in the hypothalamus and medulla oblongata. However, we observed significantly elevated NADPH oxidase in both renal cortex and medulla of Ren-2 TGR compared with HanSD. Losartan (LOS) treatment (10 mg/kg body weight/day) for 2 months (Ren-2 TGR+LOS) did not change NADPH oxidase-dependent O(2)(-) production in the kidney. We detected significantly elevated indirect markers of lipid peroxidation measured as thiobarbituric acid-reactive substances (TBARS) in Ren-2 TGR, while they were significantly decreased in Ren-2 TGR+LOS. In conclusion, the present study shows increased NADPH oxidase activities in renal cortex and medulla with significantly increased TBARS in renal cortex. No significant changes of NADPH oxidase and markers of lipid peroxidation were detected in the studied brain regions.

Effect of voluntary alcohol consumption on Maoa expression in the mesocorticolimbic brain of adult male rats previously exposed to prolonged maternal separation.

Discordant associations between monoamine oxidase A (MAOA) genotype and high alcohol drinking have been reported in human and non-human primates. Environmental influences likely moderate genetic susceptibility. The biological basis for this interplay remains elusive, and inconsistencies call for translational studies in which conditions can be controlled and brain tissue is accessible. The present study investigated whether early life stress and subsequent adult episodic alcohol consumption affect Maoa expression in stress- and reward-related brain regions in the rat. Outbred Wistar rats were exposed to rearing conditions associated with stress (prolonged maternal separation) or no stress during early life, and given free choice between alcohol and/or water in adulthood. Transcript levels of Maoa were assessed in the ventral tegmental area, nucleus accumbens (NAc), medial prefrontal cortex, cingulate cortex, amygdala and dorsal striatum (DS). Blood was collected to assess corticosterone levels. After alcohol consumption, lower blood corticosterone and Maoa expression in the NAc and DS were found in rats exposed to early life stress compared with control rats. An interaction between early life stress and voluntary alcohol intake was found in the NAc. Alcohol intake before death correlated negatively with Maoa expression in DS in high alcohol-drinking rats exposed to early life stress. Maoa expression is sensitive to adulthood voluntary alcohol consumption in the presence of early life stress in outbred rats. These findings add knowledge of the molecular basis of the previously reported associations between early life stress, MAOA and susceptibility to alcohol misuse.

Comparison of unbiased estimation of neuronal number in the rat hippocampus with different staining methods

BackgroundNeuN and Nissl staining (toluidine blue, cresyl violet staining) are routinely used methods in unbiased stereological estimation of the total number of hippocampal neurons. New methodIn the present study, we stained serial frozen coronal sections from 5 normal adult male Sprague-Dawley rat brains with different methods, measured the deformation of hippocampal area in brain sections and estimated the total number of hippocampal neurons using the optical fractionator. ResultsThe deformation in x, y-axis was not obviously different with different staining protocols, but shrinkage in z-axis was significant after staining (p<0.001). NeuN staining produced significant higher estimate number than cresyl violet staining by 24% (p=0.002), however, NeuN and Cresyl Violet staining showed a high degree of correlation in quantification of total neuronal numbers and both methods are suitable for unbiased stereological estimation. Comparison with existing method (s)NeuN is more reliable but if time is limited or the number of animals used in experiments is high, cresyl violet staining may be a feasible method. ConclusionsCompared with previous estimates of the neurons number in rat hippocampus, our present data is reliable and the stereological analysis based on our system is a cost-effective unbiased method for estimation of neuron number.

Different protocols of treadmill exercise induce distinct neuroplastic effects in rat brain motor areas

A variety of exercise protocols have been used to promote experimental neuroplasticity. However, the plastic brain responses generated by several aspects of training (types, frequency, regimens, duration) remain undetermined. The aim of this study was to compare the plastic changes in the glutamatergic system and synaptic proteins in motor cortex, striatum and cerebellum promoted by two different treadmill exercise regimens. The present study analyzed by immunohistochemistry and Western blotting the expression of the subunits of AMPA receptors (GluA1 and GluA2/3) and synaptic proteins (synapsin I and synaptophysin) in adult male Wistar rat brains. The animals were divided into animals subjected to two different frequencies of aerobic exercise groups and sedentary animals. The exercise groups were: intermittent treadmill exercise (ITE) – animals that exercised 3 times a week (every other day) during four weeks, and continuous treadmill exercise (CTE) – animals that exercised every day during four weeks. Our results reveal that different protocols of treadmill exercise were able to promote distinct synaptic reorganization processes among the exercised groups. In general, the intermittent exercise regimen induced a higher expression of presynaptic proteins, whereas the continuous exercise regimen increased postsynaptic GluA1 and GluA2/3 receptors.

Toxic Potentials of Aluminum Exposure on the Brain, Liver and Kidney in Adult Male Albino Rats: Biochemical, Histopathological and Immunohistochemical Study

Aluminum (Al) is a toxic metal and exposure to it in various ways is unavoidable owing to its abundant presence and use in everyday life Aluminum exposure leads to serious, lifethreatening complications as it accumulates in all tissues of mammals. Twenty four adult male albino rats were equally divided into three groups; group I was used as a negative control, group II received normal saline intraperitoneally (positive control group) and group III received Aluminum chloride (Al Cl3) intraperitoneally at 10 mg/kg body weight/day (1/ 20 of LD50) for 30 days (treated group). At the end of the experimental period, blood was withdrawn for estimating liver and kidney functions (serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), blood urea nitrogen and creatinine levels respectively). Then the rats were sacrificed and the brain, liver and kidney were examined by light microscope for detecting histopathological changes. Tissue sections were examined immunohistochemically for the detection of the caspase 3 (apoptosis-related cytosine peptidase) protein immunoreactions activity. In Al Cl3 reated group (group III), there were significant increases in serum AST, ALT, blood urea nitrogen and creatinine. Histopathological changes were in the form of: neuronal degeneration of the cerebral cortex with increased number of pyramidal cells and fibrillary background of the brain, dilated congested central vein, loss of cord arrangement of hepatocytes and lipid accumulation in the hepatocytes of the liver, and dilated swollen glomeruli with obstruction in renal tubules of the kidney. Cytoplasmic caspase 3 protein showed strong immunoreaction in neuronal cells, hepatocytes and renal tissues. On the light of the results of the present study, it can be concluded that Al Cl3 induced toxic injuries in the brain, liver and kidney as evidenced by biochemical, histopathological and immunohistochemical changes.