Multiple Early Life Stressors as Risk Factors for Neurodevelopmental Abnormalities in the F1 Wistar Rats.

Cumulative exposure to multiple early life stressors is expected to affect behavioral development, causing increased susceptibility to neuropsychiatric disorders. The present study was designed to mimic such conditions in a rat model to study behavioral impairments during adolescence and adulthood. Female Wistar rats (n = 32; 140-150 gm) were switched to a low protein (LP; 8% protein) or control (20% protein) diet 15 days prior to conception, and then the diet regime was maintained throughout the experimental period. Pups born to control and LP dams were intraperitoneally injected with deltamethrin (DLT-pyrethroid insecticide; 0.7 mg/kg body weight; PND 1 to 7), lipopolysaccharide (LPS-bacterial endotoxin; 0.3 mg/kg body weight; PND 3 and 5), or DLT+LPS, on designated days forming eight experimental groups (Control, LP, Control+LPS, LP+LPS, Control+DLT, LP+DLT, Control+DLT+LPS and LP+DLT+LPS). Neurobehavioral assessments were performed in F1 rats (1, 3, 6 months) by open field, elevated plus maze, light and dark box, and rotarod tests. LP rats were found to be highly susceptible to either singular or cumulative exposure as compared to their age-matched control counterparts, showing significantly severe behavioral abnormalities, such as hyperactivity, attention deficits and low anxiety, the hallmark symptoms of neuropsychiatric disorders like schizophrenia and ADHD, suggesting thereby that early life multi-hit exposure may predispose individuals to developmental disorders.

Astrogliosis and associated CSPG upregulation adversely affect dendritogenesis, spinogenesis and synaptic activity in the cerebellum of a double-hit rat model of protein malnutrition (PMN) and lipopolysaccharide (LPS) induced bacterial infection.

The extracellular matrix (ECM) plays a vital role in growth, guidance and survival of neurons in the central nervous system (CNS). The chondroitin sulphate proteoglycans (CSPGs) are a type of ECM proteins that are crucial for CNS homeostasis. The major goal of this study was to uncover the effects of astroglial activation and associated intensified expression of CSPGs on dendritogenesis, spinogenesis as well as on synaptic activity in cerebellum following protein malnutrition (PMN) and lipopolysaccharide (LPS) induced bacterial infection. Female Wistar albino rats (3 months old) were switched to control (20% protein) or low protein (LP, 8% protein) diet for 15 days followed by breeding. A set of pups born to control/LP mothers and maintained on respective diets throughout the experimental period constituted the control and LP groups, while a separate set of both control and LP group pups exposed to bacterial infection by a single intraperitoneal injection of LPS (0.3 mg/ kg body weight) on postnatal day-9 (P-9) constituted control+LPS and LP+LPS groups respectively. The consequences of astrogliosis induced CSPG upregulation on cerebellar cytoarchitecture and synaptic activity were studied using standard immunohistochemical and histological tools on P-21 and 6 months of age. The results revealed reactive astrogliosis and associated CSPG upregulation in a double-hit model of PMN and LPS induced bacterial infection resulted in disrupted dendritogenesis, reduced postsynaptic density protein (PSD-95) levels and a deleterious impact on normal spine growth. Such alterations frequently have the potential to cause synaptic dysregulation and inhibition of plasticity both during development as well as adulthood. At the light of our results, we can envision that upregulation of CSPGs in PMN and LPS co-challenged individuals might emerge as an important modulator of brain circuitry and a major causative factor for many neurological disorders.

Perineuronal nets: Cruise from a honeycomb to the safety nets.

The extracellular matrix (ECM) is a significant component of the brain, constituting up to 20 % of the brain volume and perform multifarious functions during development, maturation and regeneration of the central nervous system (CNS). ECM molecules assemble systematically to form a relatively rigid and unique lattice-like structure, known as perineuronal nets (PNNs). The PNNs usually envelop the cell body and initial axon segment and are characterized by a mesh-like structure extending along dendrites of neurons. PNNs play prominent role in the early neural development, from migration and differentiation to axonal path finding. They regulate plasticity and regeneration in adulthood by surrounding and stabilizing synaptic contacts. In this review, we have focused on the basic structure, distribution and visualization of PNNs and their role during critical periods of development, synaptogenesis and regulation of synaptic plasticity. Furthermore, we have also tried to evaluate the participation of PNNs in the pathophysiology of several brain disorders and their potential in lowering local oxidative stress. Taken together, the concepts outlined in this review emphasize the heterogeneity of PNNs in response to normal physiological and pathological conditions, highlighting the need for future studies on PNNs to target their role in etiology and potential therapeutic interventions in neurological disorders.

Perinatal exposure to synergistic multiple stressors leads to cellular and behavioral deficits mimicking Schizophrenia-like pathology.

Protein malnourishment and immune stress are potent perinatal stressors, encountered by children born under poor socioeconomic conditions. Thus, it is necessary to investigate how such stressors synergistically contribute towards developing neurological disorders in affected individuals. Pups from Wistar females, maintained on normal (high-protein, HP:20%) and low-protein (LP:8%) diets were used. Single and combined exposures of Poly I:C (viral mimetic: 5 mg/kg body weight) and Lipopolysaccharide (LPS; bacterial endotoxin: 0.3 mg/kg body weight) were injected to both HP and LP pups at postnatal days (PND) 3 and 9 respectively, creating eight groups: HP (control); HP+Poly I:C; HP+LPS; HP+Poly I:C+LPS; LP; LP+Poly I:C; LP+LPS; LP+Poly I:C+LPS (multi-hit). The effects of stressors on hippocampal cytoarchitecture and behavioral abilities were studied at PND 180. LP animals were found to be more vulnerable to immune stressors than HP animals and symptoms like neuronal damage, spine loss, downregulation of Egr 1 and Arc proteins, gliosis and behavioral deficits were maximum in the multi-hit group. Thus, from these findings it is outlined that cellular and behavioral changes that occur following multi-hit exposure may predispose individuals to developing Schizophrenia-like pathologies during adulthood.

Early life exposure to poly I:C impairs striatal DA-D2 receptor binding, myelination and associated behavioural abilities in rats.

Early-life viral infections critically influence the brain development and have been variously reported to cause neuropsychiatric diseases such as Schizophrenia, Parkinson's diseases, demyelinating diseases, etc. To investigate the alterations in the dopaminergic system, myelination and associated behavioral impairments following neonatal viral infection, the viral immune activation model was created by an intraperitoneal injection of Poly I:C (5 mg/kg bw/ip) to neonatal rat pups on PND-7. The DA-D2 receptor binding was assessed in corpus striatum by using 3H-Spiperone at 3, 6 and 12 weeks of age. MOG immunolabelling was performed to check myelination stature and myelin integrity, while corpus callosum calibre was assessed by Luxol fast blue staining. Relative behavioral tasks i.e., motor activity, motor coordination and neuromuscular strength were assessed by open field, rotarod and grip strength meter respectively at 3, 6 and 12 weeks of age. Following Poly I:C exposure, a significant decrease in DA-D2 receptor binding, reduction in corpus callosum calibre and MOG immunolabelling indicating demyelination and a significant decrease in locomotor activity, neuromuscular strength and motor coordination signify motor deficits and hypokinetic influence of early life viral infection. Thus, the findings suggest that early life poly I:C exposure may cause demyelination and motor deficits by decreasing DA-D2 receptor binding affinity.

Maternal Spirulina supplementation during pregnancy and lactation partially prevents oxidative stress, glial activation and neuronal damage in protein malnourished F1 progeny.

Protein malnutrition (PMN) is a global health issue but most prevalent in Africa and Asia. It exerts detrimental effect on structural and physiological aspects of hippocampal circuitry. Despite accumulating evidence for PMN induced changes in nervous system, relatively very little is known about how maternal nutritional supplementation during malnutrition affects glial cells and neurons. Herein, we aimed to investigate the effects of maternal Spirulina supplementation against PMN induced oxidative stress, reactive gliosis and neuronal damage in hippocampus of F1 progeny. Three months old healthy Sprague Dawley females (n = 24) were shifted to normoprotein (NC; 20% protein) and low protein (LP; 8% protein) diets 15 days before conception. The NC and LP group females were subdivided into two groups according to Spirulina supplementation (400 mg/kg/b.wt. orally throughout gestation and lactation period): normal control with Spirulina (NC SPI) and low protein with Spirulina supplemented group (LP SPI). F1 progeny born were used in present study. Thus, building on earlier results of ameliorated neurobehavioral and cognitive abilities in Spirulina supplemented protein deprived rats, the present study incorporates neurochemical and morphometric analysis of glial cells and neurons and revealed that maternal Spirulina consumption partially prevented the PMN associated neuropathological alterations in terms of attenuated oxidative brain damage, reduced reactive gliosis and apoptotic cell population, improved dendritic branch complexity with few damaged neurons and enhanced mushroom shaped spine density. The results suggest that cellular changes in hippocampus after PMN are partially restored after maternal Spirulina supplementation and one could envision intervention approaches using Spirulina against malnutrition.

Neuronal changes and cognitive deficits in a multi-hit rat model following cumulative impact of early life stressors.

Perinatal protein malnourishment (LP) is a leading cause for mental and physical retardation in children from poor socioeconomic conditions. Such malnourished children are vulnerable to additional stressors that may synergistically act to cause neurological disorders in adulthood. In this study, the above mentioned condition was mimicked via a multi-hit rat model in which pups born to LP mothers were co-injected with polyinosinic:polycytidylic acid (Poly I:C; viral mimetic) at postnatal day (PND) 3 and lipopolysaccharide (LPS; bacterial mimetic) at PND 9. Individual exposure of Poly I:C and LPS was also given to LP pups to correlate chronicity of stress. Similar treatments were also given to control pups. Hippocampal cellular apoptosis, ß III tubulin catastrophe, altered neuronal profiling and spatial memory impairments were assessed at PND 180, using specific immunohistochemical markers (active caspase 3, ß III tubulin, doublecortin), golgi studies and cognitive mazes (Morris water maze and T maze). Increase in cellular apoptosis, loss of dendritic arborization and spatial memory impairments were higher in the multi-hit group, than the single-hit groups. Such impairments observed due to multi-hit stress mimicked conditions similar to many neurological disorders and hence, it is hypothesized that later life neurological disorders might be an outcome of multiple early life hits.This article has an associated First Person interview with the first author of the paper.

Amelioration of neurobehavioral and cognitive abilities of F1 progeny following dietary supplementation with Spirulina to protein malnourished mothers.

Early life adversities (stress, infection and mal/undernutrition) can affect neurocognitive, hippocampal and immunological functioning of the brain throughout life. Substantial evidence suggests that maternal protein malnutrition contributes to the progression of neurocognitive abnormalities and psychopathologies in adolescence and adulthood in offspring. Maternal malnutrition is prevalent in low and middle resource populations. The present study was therefore undertaken to evaluate the effects of dietary Spirulina supplementation of protein malnourished mothers during pregnancy and lactation on their offspring's reflex, neurobehavioral and cognitive development. Spirulina is a Cyanobacterium and a major source of protein and is being used extensively as a dynamic nutraceutical against aging and neurodegeneration. Sprague Dawley rats were switched to low protein (8% protein) or normal protein (20% protein) diet for 15 days before conception. Spirulina was orally administered (400 mg/kg/b.wt.) to subgroups of pregnant females from the day of conception throughout the lactational period. We examined several parameters including reproductive performance of dams, physical development, postnatal reflex ontogeny, locomotor behavior, neuromuscular strength, anxiety, anhedonic behavior, cognitive abilities and microglia populations in the F1 progeny. The study showed improved reproductive performance of Spirulina supplemented protein malnourished dams, accelerated acquisition of neurological reflexes, better physical appearance, enhanced neuromuscular strength, improved spatial learning and memory and partly normalized PMN induced hyperactivity, anxiolytic and anhedonic behavior in offspring. These beneficial effects of Spirulina consumption were also accompanied by reduced microglial activation which might assist in restoring the behavioral and cognitive skills in protein malnourished F1 rats. Maternal Spirulina supplementation is therefore proposed as an economical nutraceutical/supplement to combat malnutrition associated behavioral and cognitive deficits.

Cumulative multiple early life hits- a potent threat leading to neurological disorders.

Early life Stress is a worldwide concern linked with development of later life neurological disorders. Early developmental age is sensitive to many prominent environmental insults like malnourishment, immune inflammation, abuse, maternal separation, alcohol and drugs. Hence, an individual during an early age encounters more than one simultaneous stressor that leads to impairment of cognitive and behavioral abilities, a symptom common to most of the neurological disorders. Stressors like malnourishment and immune inflammation are common and encountered by a huge number of populations, contributing enormously to a damaged CNS and in most of the cases they act synergistically in dependency to each other, giving rise to the concept of multi-hit. Multi perinatal hit acts by mimicking the mechanism of ageing in CNS and increasing the risk for later life neurological disorders. Multi stress exposure is also responsible for disrupting the cellular homeostasis of the brain by inducing glial activation, neurotoxicity and oxidative stress, which is the major reason of cell death and circuitry damage in brain. Multi perinatal hit thus increases the risk of neurological disorders by many folds through interfering with ongoing developmental cascades and eventually modulating the fate of cellular components in brain. Thus, a stress induced architecturally and chemically altered CNS is vulnerable and prone to neurological disorders like Alzheimer's, Schizophrenia, ALS, Autism and Parkinson's disease. This review compiles the information available regarding the effects of early life stressors on different components of brain, primarily focusing on the connection between perinatally encountered multi hit and development of later life neurological disorders.

Developmental Changes in Oligodendrocyte Genesis, Myelination, and Associated Behavioral Dysfunction in a Rat Model of Intra-generational Protein Malnutrition.

Impairments in oligodendrocyte development and resultant myelination deficits appear as a common denominator to all neurological diseases. An optimal in utero environment is obligatory for normal fetal brain development and later life brain functioning. Late embryonic and early postnatal brains from F1 rat born to protein malnourished mothers were studied through a combination of immunocytochemical and quantitative PCR assay for analyzing the relative expression of platelet-derived growth factor receptor-α (PDGFRα), myelin-associated glycoprotein (MAG), proteolipid protein (PLP), and myelin oligodendrocyte glycoprotein (MOG) to determine oligodendrocyte genesis, differentiation, maturation, and myelination. Myelin integrity and corpus callosum caliber was assessed by Luxol fast blue (LFB) staining, whereas grip strength test and open field activity monitoring for behavioral evaluation in F1 rats. We demonstrate that intra-generational protein deprivation results in drastically low PDGFRα+ oligodendrocyte precursor (OPC) population and significantly reduced expression of myelin protein genes resulting in poor pre-myelinating and mature myelinating oligodendrocyte number, hypo-myelination, and misaligned myelinated fibers. LFB staining and MOG immunolabeling precisely revealed long-term changes in corpus callosum (CC) caliber and demyelination lesions in LP brain supporting the behavioral and cognitive changes at early adolescence and adulthood following maternal protein malnutrition (PMN). Thus, intra-generational PMN negatively affects the oligodendrocyte development and maturation resulting in myelination impairments and associated with behavioral deficits typically mimicking clinical hallmarks of neuropsychiatric disorders. Our results further strengthen and augment the hypothesis "Impaired gliogenesis is a big hit for neuropsychiatric phenotype."

Poly (I:C) Exposure in Early Life Alters Methylation of DNA and Acetylation of Histone at Synaptic Plasticity Gene Promoter in Developing Rat Brain Leading to Memory Impairment.

BACKGROUND: Exposure to adverse environmental conditions such as toxic chemicals, viral infections, and even stress during pregnancy or early life may disrupt the development of normal brain and its functioning leading to incidence of neurodevelopmental disorders at later stages of life. Recently, we reported that poly (I:C) exposure altered synaptic plasticity protein level and impaired memory through activation of microglia cells. PURPOSE: As epigenetic modifications are involved in memory formation, we have studied methylation of DNA and acetylation of histone at promoters of synaptic plasticity genes in the brain of rats exposed to poly (I:C) during early life. METHODS: One dose of poly (I:C) (5 mg/kg bw) was intraperitoneally injected to rat pups on postnatal seventh day. A set of pups exposed to vehicle was included as control. In order to assess methylation of DNA and acetylation of histone at synaptic plasticity gene promoter, we performed qPCR after methylated DNA immunoprecipitation and chromatin immunoprecipitation. RESULTS: Poly (I:C) exposure reduced the level of 5-methylcytosine (5mC) at synaptic plasticity gene (bdnf, arc, and egr1) promoters in the frontal cortex (FC) and hippocampus of 3-week rats, although increased it later in both regions of 12-week rats as compared to respective controls. On contrary, poly (I:C) exposure enhanced acetylation of histone H3K9 (H3K9Ac) at promoters of these genes in both regions of 3-week rats but decreased in 12-week rats. CONCLUSION: Poly (I:C) exposure altered 5mC and H3K9Ac at synaptic plasticity gene promoters resulting in memory impairment of rats at later life.

Postnatal exposure to poly (I:C) impairs learning and memory through changes in synaptic plasticity gene expression in developing rat brain.

Viral infection during early stage of life influences brain development and results in several neurodevelopmental disorders such as schizophrenia, autism and behavioral abnormalities. However, the mechanism through which infection causes long-term behavioral defects is not well known. To elucidate this, we have used synthetic polyinosinic-polycytidylic acid [poly (I:C)] which acts as a dsRNA molecule and interacts with toll-like receptor-3 (TLR-3) of microglia cells to evoke the immune system, thus mimicking the viral infection. Rat pups of postnatal day (PND) 7 were infused with a single dose of poly (I:C) (5 mg/kg BW) and vehicle alone to controls. When these pups grew to 3, 6 and 12 weeks, their spatial and fear conditioning memory were impaired as assessed by Morris water maze and passive avoidance test, respectively. We checked the immune activation by staining of TNF-α in the hippocampus and observed that poly (I:C) exposure elevated the number of TNF-α positive cells immediately after 12 h of infusion in one week rat and it persisted up to postnatal age of 3 and 12 weeks. Moreover, poly (I:C) significantly decreased the binding of 3H-QNB to the cholinergic receptors in the frontal cortex and hippocampus of 3 and 6 weeks rats as compared to control but did not change significantly in 12 weeks rats. RT-PCR and immunoblotting results showed that poly (I:C) exposure upregulated the expression of memory associated genes (BDNF, Arc, EGR1) at mRNA and protein level in frontal cortex and hippocampus of 3 weeks rats as compared to control. However, long-time persistence of poly (I:C) effects significantly decreased the expression of these genes in both brain regions of 12 weeks rats. Taken together, it is evident that early life exposure to poly (I:C) has a long-term effect and impairs learning and memory, probably through TNF-α mediated neuroinflammation and alteration in the expression of memory associated genes in frontal cortex and hippocampus of rats.

Maternal Protein Malnutrition: Current and Future Perspectives of Spirulina Supplementation in Neuroprotection.

Malnutrition has been widely recognized as a grave burden restricting the progress of underdeveloped and developing countries. Maternal, neonatal and postnatal nutritional immunity provides an effective approach to decrease the risk of malnutrition associated stress in adulthood. Particularly, maternal nutritional status is a critical contributor for determining the long-term health aspects of an offspring. Maternal malnutrition leads to increased risk of life, poor immune system, delayed motor development and cognitive dysfunction in the children. An effective immunomodulatory intervention using nutraceutical could be used to enhance immunity against infections. The immune system in early life possesses enormous dynamic capacity to manage both genetic and environment driven processes and can adapt to rapidly changing environmental exposures. These immunomodulatory stimuli or potent nutraceutical strategy can make use of early life plasticity to target pathways of immune ontogeny, which in turn could increase the immunity against infectious diseases arising from malnutrition. This review provides appreciable human and animal data showing enduring effects of protein deprivation on CNS development, oxidative stress and inflammation and associated behavioral and cognitive impairments. Relevant studies on nutritional supplementation and rehabilitation using Spirulina as a potent protein source and neuroprotectant against protein malnutrition (PMN) induced deleterious changes have also been discussed. However, there are many futuristic issues that need to be resolved for proper modulation of these therapeutic interventions to prevent malnutrition.

A Sequential Study of Age-Related Lipofuscin Accumulation in Hippocampus and Striate Cortex of Rats.

BACKGROUND: The age-pigment, lipofuscin that accumulates in cells intrinsically and progressively with age is considered as the hallmark of aging. This accumulation is more prominent in post-mitotic cells like neurons and also appears in glia. PURPOSE: The aim of the present study was to assess the age-associated occurrence and distribution pattern of lipofuscin both in neurons and microglia in various regions of hippocampus and striate cortex. METHODS: The accumulation pattern of lipofuscin in hippocampus and striate cortex was observed in the female Wistar rats of 6 age groups, that is, 3, 6, 12, 18, 24, and 30 months using the autofluorescent property of lipofuscin and its specific localization in neurons and microglia by dual immunolabeling with NeuN and Iba-1 antibodies respectively. Cytoarchitectural and the morphological age-related changes were observed with cresyl violet staining. RESULTS: Lipofuscin pigments accumulate progressively through the normal aging process in hippocampus and striate cortex. However, in hippocampus, lipofuscin accumulates in a region-specific manner with the highest accumulation observed in cornu ammonis (CA) 1 and 3 subregions. Furthermore, the lipofuscin accumulation was also observed in microglia in the senile brains both in the hippocampus and striate cortex. CONCLUSION: The progressive deposition of lipofuscin could result in cellular dysfunction. This encouraged us to forward the idea that microglia not only participate in the removal of the pigment from the neurons but also accumulate these waste products in itself. Such senescent microglia may contribute to age- related neurodegeneration as they lose the neuroprotective potential due to oxidative stress and thus may be unable to effectively phagocytose the age pigment.

Neonatal Lipopolysaccharide Infection Causes Demyelination and Behavioral Deficits in Adult and Senile Rat Brain.

BACKGROUND: Neonatal bacterial infections have been reported to cause white matter loss, although studies concerning the influence of infection on the expression of myelin and aging are still in their emerging state. PURPOSE: The present study aimed to investigate the effects of perinatal lipopolysaccharide (LPS) exposure on the myelination at different age points using histochemical and immunocytochemical techniques and the relative motor coordination. METHODS: A rat bacterial infection model was established by exposing the neonatal rats with LPS (0.3 mg/kg body weight, i.p., on postnatal day (PND) 3 followed by a booster at PND 5) and its impact was studied on the myelination and motor coordination in young, adult, and senile rats. RESULTS: The results obtained suggest that the administration of LPS induces demyelination, predominantly in cortex and corpus callosum. Low expression level of myelin oligodendrocyte glycoprotein (MOG) was observed at all time points, with prominence at 12, 18, and 24 months of age. In addition, reduced staining with luxol fast blue stain was also recorded in the experimentals. With the increasing demyelination and declining motor ability, LPS exposure also seemed to accelerate normal aging symptoms. CONCLUSION: There is a direct correlation of myelin damage and poor motor coordination with age. This would provide a better incite to understand inflammation-associated demyelinating changes in age-associated neurodegenerative disorders. Since, no long-term studies on behavioral impairments caused by LPS-induced demyelination in the central nervous system has been reported so far, this work would help in the better understanding of the long-term pathological effects of bacterial-induced demyelination.

Intra-generational protein malnutrition impairs temporal astrogenesis in rat brain.

The lack of information on astrogenesis following stressor effect, notwithstanding the imperative roles of astroglia in normal physiology and pathophysiology, incited us to assess temporal astrogenesis and astrocyte density in an intra-generational protein malnutrition (PMN) rat model. Standard immunohistochemical procedures for glial lineage markers and their intensity measurements, and qRT-PCR studies, were performed to reveal the spatio-temporal origin and density of astrocytes. Reduced A2B5+ glia restricted precursor population in ventricles and caused poor dissemination to cortex at embryonic days (E)11-14, and low BLBP+ secondary radial glia in the subventricular zone (SVZ) of E16 low protein (LP) brains reflect compromised progenitor pooling. Contrary to large-sized BLBP+ gliospheres in high protein (HP) brains at E16, small gliospheres and discrete BLBP+ cells in LP brains evidence loss of colonization and low proliferative potential. Delayed emergence of GFAP expression, precocious astrocyte maturation and significantly reduced astrocyte number suggest impaired temporal and compromised astrogenesis within LP-F1 brains. Our findings of protein deprivation induced impairments in temporal astrogenesis, compromised density and astrocytic dysfunction, strengthen the hypothesis of astrocytes as possible drivers of neurodevelopmental disorders. This study may increase our understanding of stressor-associated brain development, opening up windows for effective therapeutic interventions against debilitating neurodevelopmental disorders.

Lipopolysaccharide-Induced Apoptosis of Astrocytes: Therapeutic Intervention by Minocycline.

Astrocytes are most abundant glial cell type in the brain and play a main defensive role in central nervous system against glutamate-induced toxicity by virtue of numerous transporters residing in their membranes and an astrocyte-specific enzyme glutamine synthetase (GS). In view of that, a dysregulation in the astrocytic activity following an insult may result in glutamate-mediated toxicity accompanied with astrocyte and microglial activation. The present study suggests that the lipopolysaccharide (LPS)-induced inflammation results in significant astrocytic apoptosis compared to other cell types in hippocampus and minocycline could not efficiently restrict the glutamate-mediated toxicity and apoptosis of astrocytes. Upon LPS exposure 76 % astrocytes undergo degeneration followed by 44 % oligodendrocytes, 26 % neurons and 10 % microglia. The pronounced astrocytic apoptosis resulted from the LPS-induced glutamate excitotoxicity leading to their hyperactivation as evident from their hypertrophied morphology, glutamate transporter 1 upregulation and downregulation of GS. Therapeutic minocycline treatment to LPS-infused rats efficiently restricted the inflammatory response and degeneration of other cell types but could not significantly combat with the apoptosis of astrocytes. Our study demonstrates a novel finding on cellular degeneration in the hippocampus revealing more of astrocytic death and suggests a more careful consideration on the protective efficacy of minocycline.

Slow Physical Growth, Delayed Reflex Ontogeny, and Permanent Behavioral as Well as Cognitive Impairments in Rats Following Intra-generational Protein Malnutrition.

Environmental stressors including protein malnutrition (PMN) during pre-, neo- and post-natal age have been documented to affect cognitive development and cause increased susceptibility to neuropsychiatric disorders. Most studies have addressed either of the three windows and that does not emulate the clinical conditions of intra-uterine growth restriction (IUGR). Such data fail to provide a complete picture of the behavioral alterations in the F1 generation. The present study thus addresses the larger window from gestation to F1 generation, a new model of intra-generational PMN. Naive Sprague Dawley (SD) dams pre-gestationally switched to LP (8% protein) or HP (20% protein) diets for 45 days were bred and maintained throughout gestation on same diets. Pups born (HP/LP dams) were maintained on the respective diets post-weaningly. The present study aimed to show the sex specific differences in the neurobehavioral evolution and behavioral phenotype of the HP/LP F1 generation pups. A battery of neurodevelopmental reflex tests, behavioral (Open field and forelimb gripstrength test), and cognitive [Elevated plus maze (EPM) and Morris water maze (MWM)] assays were performed. A decelerated growth curve with significantly restricted body and brain weight, delays in apparition of neuro-reflexes and poor performance in the LP group rats was recorded. Intra-generational PMN induced poor habituation-with-time in novel environment exploration, low anxiety and hyperactive like profile in open field test in young and adult rats. The study revealed poor forelimb neuromuscular strength in LP F1 pups till adulthood. Group occupancy plots in MWM test revealed hyperactivity with poor learning, impaired memory retention and integration, thus modeling the signs of early onset Alzehemier phenotype. In addition, a gender specific effect of LP diet with severity in males and favoring female sex was also noticed.

Differential temporal expression of S100ß in developing rat brain.

Radial glial cells (RGs) originally considered to provide scaffold to the radially migrating neurons constitute a heterogeneous population of the regionally variable precursor cells that generate both neurons as well as glia depending upon the location and the timing of development. Hence specific immunohistochemical markers are required to specify their spatiotemporal location and fate in the neurogenic and gliogenic zones. We hypothesize S100ß as a potential and unified marker for both primary and secondary progenitors. To achieve this, cryocut sections from rat brains of varied embryonic and postnatal ages were immunolabeled with a combination of antibodies, i.e., S100ß + Nestin, Nestin + GFAP and S100ß + GFAP. A large population of the primary and secondary progenitors, lining the VZ and SVZ, simultaneously co-expressed S100ß and nestin establishing their progenitor nature. A downregulation of both S100ß and nestin noticed by the end of the 1st postnatal week marks their differentiation towards neuronal or glial lineage. In view of the absence of co-expression of GFAP (glial fibrillary acidic protein) either with S100ß or nestin, the suitability of accepting GFAP as an early marker of RG's was eliminated. Thus the dynamic expression of S100ß in both the neural stem cells (NSCs) and RGs during embryonic and early neonatal life is associated with its proliferative potential and migration of undifferentiated neuroblasts and astrocytes. Once they lose their potential for proliferation, the S100ß expression is repressed with its reemergence in mature astrocytes. This study provides the first clear evidence of S100ß expression throughout the period of neurogenesis and early gliogenesis, suggesting its suitability as a radial progenitor cell marker.

Glial alterations in tuberculous and cryptococcal meningitis and their relation to HIV co-infection--a study on human brains.

INTRODUCTION: Tuberculosis and cryptococcal infection of the central nervous system are common AIDS-associated opportunistic infections in tropical underdeveloped and developing countries. To date, research on these infections has focused on clinical, imaging, laboratory diagnosis, and animal models to elucidate the pathogenesis. There is paucity of information on astroglial and microglial alterations in the human nervous system following these infections. METHODOLOGY: The pathomorphologic and morphometric alterations of astroglia and microglia in the prefrontal cortex and hippocampus in cases of tuberculous meningitis (TBM) and cryptococcal meningitis (CM) with and without associated HIV were described and compared with cases of HIV encephalitis without opportunistic infections (OI) and HIV-negative human brain tissue. RESULTS: In TBM, the microglia and astrocytes were activated with hypertrophy and hyperplasia, aggregating in the subpial zone and around granulomas in meningeal exudate. In cases of cryptococcal meningitis, reactive changes were less prominent, though activation of both cellular elements was found. Association of HIV with these OIs resulted in muted glial and microglial response. In HIV encephalitis without OI, the level of activation of was low. Both astroglial and microglial cells expressed caspase-3, a pro-apoptotic marker, following HIV and opportunistic infections. Neuronal apoptosis, a mechanism to ensure neuronal survival, was less evident. The reactive astrocytes and microglia following opportunistic infection developed dystrophic changes heralding senescence. CONCLUSIONS: Further studies on neuronal-astroglial-microglial interaction will offer deeper insight into the pathogenetic and immune mechanisms in the cellular and pathomorphological evolution of tuberculous and cryptococcal infections.