Negative geotaxis: An early age behavioral hallmark to VPA rat model of autism

Developmental and reproductive toxicity (DART) study of a novel SARS-CoV-2 tetravalent recombinant protein vaccine (SCTV01E) in rats

SCTV01E, a novel SARS-CoV-2 tetravalent protein vaccine containing recombinant spike proteins of Alpha (B.1.1.7), Beta (B.1.351), Delta (B.1.617.2) and Omicron BA.1 (B.1.1.529.1) variants and SCTVA02B adjuvant, has received Emergency Use Authorization (EUA) in China and the United Arab Emirates (UAE) as a next-generation COVID-19 vaccine. A comprehensive reproductive and developmental toxicity evaluation was conducted in Sprague-Dawley (SD) rats under Good Laboratory Practice (GLP) conditions. Maternal animals were intramuscularly injected with 1 × or 3 × the highest human dose every other week prior to mating, followed by booster immunizations during gestation and lactation periods. The main findings showed that SCTV01E vaccination elicited robust binding IgG and neutralizing antibody responses against all four target variants. While no vaccine-related adverse reproductive effects were observed in parental male or female rats, transient injection site reactions and slight, reversible reductions in body weight gain and food consumption were noted. Key developmental parameters were not affected, and postnatal evaluation revealed no evidence of embryo-fetal malformations, developmental delays, or functional impairments in offspring. These results suggest a favorable safety profile for SCTV01E and its possible suitability for clinical trials in humans of reproductive potential. Furthermore, the efficient transplacental and lactational transfer of maternal antibodies observed in animal models suggests a potential protection: direct immunization of mothers may confer passive immunity to both fetuses in utero and neonates during breastfeeding.

Modulation of dopamine, serotonin, and behavior by lutein carrier nanoparticles in a Drosophila melanogaster model of neurodevelopmental disorders

Considering that woman's health during pregnancy is crucial to well-being as much maternal and fetal as well as the child's future, supplementation with antioxidant compounds has emerged as a promising strategy to prevent the development of future diseases. Given this context, the study aimed to evaluate the effect of lutein carrier nanoparticles supplementation during the preconception period on the offspring of Drosophila melanogaster subjected to a neurodevelopmental disorder model. Female flies, were exposed to either a standard diet or a diet containing NPs LUT (6 μM) for 24 h. Following this period, the flies were transferred to new experimental vials, and eighteen males were added, resulting in a total of 53 flies per experimental group. The male and female flies were then subdivided into two groups and exposed to either a standard diet or imidacloprid (IMI), for 7 days, to induce the neurodevelopmental disorder model, creating four experimental groups: 1) Control; 2) IMI; 3) NPs LUT; 4) NPs LUT + IMI. The hatched offspring were then used for behavioral and biochemical evaluations. Our results showed that supplementation with lutein carrier nanoparticles was able to prevent decreased activity of enzyme tyrosine hydroxylase (TH), as did neurotransmitters dopamine (DA) and serotonin (5-HT) in the head of flies, and as a consequence it prevented behavioral damages such as hyperactivity, anxiety, social interaction, repetitive movements, learning and memory in the progeny of both sexes. Thus, these findings highlight the relevance of preconception supplementation with lutein carrier nanoparticles as an effective approach to prevent the emergence of symptoms associated with neuropsychiatric disorders, paving the way for future research aimed at investigating the best intervention period to prevent ASD and ADHD-type disorders.

Impact of preconceptional intermittent fasting on reflex ontogenesis, physical and somatic development of the offspring of Wistar rats

BACKGROUND

Intermittent fasting (IF) has health benefits; however, little is known about its effects on the offspring when practiced by dams in the preconception period. The aim of the study was to evaluate the impact of IF during the preconception period on physical and somatic parameters, as well as on the reflex ontogenesis of Wistar rat offspring.

METHODS

The female rats were randomized into two groups: control (CG) and intermittent fasting group (IF) submitted to a feed restriction of 16 h for four weeks during the preconception period. Reproductive performance, body weight, and energy intake were evaluated in dams. Reflex ontogeny, physical and somatic development, brain fatty acids and the brain histology were evaluated in the offspring.

RESULTS

IF did not change the reproductive performance or weight of dams during the preconception period. An acceleration of vibrissae placing and negative geotaxis parameters of reflex ontogenesis was observed, as well as anticipation of the following physical development indicators: ear unfolding, an eruption of upper incisor teeth, and inferior teeth in the IF offspring. Although the nervous tissue did not present histological changes, the content of some brain fatty acids was found in greater amounts in the IF offspring such as dihomo-γ-linolenic acid (0.66 ± 0.01 %) and eicotrienoic acid (0.58 ± 0.03 %).

CONCLUSION

IF during preconception did not change the body weight or reproductive performance of the dams, and promoted beneficial effects on the neurodevelopment of the offspring in the early life.

Construction of an animal model of autism based on interaction between cerebellar histological, immunohistochemical, and biochemical changes in adult male albino rat

METHODS

Twelve pregnant female rats were divided into a control group and a valproic acid (VPA) treated group (injected intraperitoneally on embryonic day 12 with 600 mg/kg body weight of VPA). Neurobehavioral tests were conducted on the offspring of both groups. The cerebellum was studied by light and electron microscopy as well as GFAP and caspase-3 immunohistochemical staining.

RESULTS

The VPA-treated group showed signs of neuronal degeneration, such as congested blood vessels, vacuolations, irregularly shrunken with dark small heterochromatic nuclei and numerous apoptotic blebs in the Purkinje and granule cells with vacuolated cerebellar glomeruli. The myelinated nerve fibers showed rarefaction and loss of their neurofilaments. GFAP and caspase-3 immune expression were significantly altered in the VPA-treated group.

CONCLUSION

The VPA rat model can serve as an excellent model of autism at the structural level, which may be used as a validated model in preclinical studies to evaluate novel drugs.

Neuroprotective effect of PPAR gamma agonist in rat model of autism spectrum disorder: Role of Wnt/β-catenin pathway

BACKGROUND

The clinical manifestation of autism spectrum disorder (ASD) is linked to the disruption of fundamental neurodevelopmental pathways. Emerging evidences claim to have an upregulation of canonical Wnt/β-catenin pathway while downregulation of PPARγ pathway in ASD. This study aims to investigate the therapeutic potential of pioglitazone, a PPARγ agonist, in rat model of ASD. The study further explores the possible role of PPARγ and Wnt/β-catenin pathway and their interaction in ASD by using their modulators.

MATERIAL AND METHODS

Pregnant female Wistar rats received 600 mg/kg of valproic acid (VPA) to induce autistic symptoms in pups. Pioglitazone (10 mg/kg) was used to evaluate neurobehaviors, relative mRNA expression of inflammatory (IL-1β, IL-6, IL-10, TNF-α), apoptotic markers (Bcl-2, Bax, & Caspase-3) and histopathology (H&E, Nissl stain, Immunohistochemistry). Effect of pioglitazone was evaluated on Wnt pathway and 4 μg/kg dose of 6-BIO (Wnt modulator) was used to study the PPARγ pathway.

RESULTS

ASD model was established in pups as indicated by core autistic symptoms, increased neuroinflammation, apoptosis and histopathological neurodegeneration in cerebellum, hippocampus and amygdala. Pioglitazone significantly attenuated these alterations in VPA-exposed rats. The expression study results indicated an increase in key transcription factor, β-catenin in VPA-rats suggesting an upregulation of canonical Wnt pathway in them. Pioglitazone significantly downregulated the Wnt signaling by suppressing the expression of Wnt signaling-associated proteins. The inhibiting effect of Wnt pathway on PPARγ activity was indicated by downregulation of PPARγ-associated protein in VPA-exposed rats and those administered with 6-BIO.

CONCLUSION

In the present study, upregulation of canonical Wnt/β-catenin pathway was demonstrated in ASD rat model. Pioglitazone administration significantly ameliorated these symptoms potentially through its neuroprotective effect and its ability to downregulate the Wnt/β-catenin pathway. The antagonism between the PPARγ and Wnt pathway offers a promising therapeutic approach for addressing ASD.

Tissue nonspecific alkaline phosphatase deficiency impairs Purkinje cell development and survival in a mouse model of infantile hypophosphatasia

Loss-of-function mutations in the tissue-nonspecific alkaline phosphatase (TNAP) gene can result in hypophosphatasia (HPP), an inherited multi-systemic metabolic disorder that is well-known for skeletal and dental hypomineralization. However, emerging evidence shows that both adult and pediatric patients with HPP suffer from cognitive deficits, higher measures of depression and anxiety, and impaired sensorimotor skills. The cerebellum plays an important role in sensorimotor coordination, cognition, and emotion. To date, the impact of TNAP mutation on the cerebellar circuitry development and function remains poorly understood. The main objective of this study was to investigate the roles of TNAP in cerebellar development and function, with a particular focus on Purkinje cells, in a mouse model of infantile HPP. Male and female wild type (WT) and TNAP knockout (KO) mice underwent behavioral testing on postnatal day 13-14 and were euthanized after completion of behavioral tests. Cerebellar tissues were harvested for gene expression and immunohistochemistry analyses. We found that TNAP mutation resulted in significantly reduced body weight, shorter body length, and impaired sensorimotor functions in both male and female KO mice. These developmental and behavioral deficits were accompanied by abnormal Purkinje cell morphology and dysregulation of genes that regulates synaptic transmission, cellular growth, proliferation, and death. In conclusion, inactivation of TNAP via gene deletion causes developmental delays, sensorimotor impairment, and Purkinje cell maldevelopment. These results shed light on a new perspective of cerebellar dysfunction in HPP.

Impairment of neuromotor development and cognition associated with histopathological and neurochemical abnormalities in the cerebral cortex and striatum of glutaryl-CoA dehydrogenase deficient mice

Patients with glutaric acidemia type I (GA I) manifest motor and intellectual disabilities whose pathogenesis has been so far poorly explored. Therefore, we evaluated neuromotor and cognitive abilities, as well as histopathological and immunohistochemical features in the cerebral cortex and striatum of glutaryl-CoA dehydrogenase (GCDH) deficient knockout mice (Gcdh-/-), a well-recognized model of GA I. The effects of a single intracerebroventricular glutaric acid (GA) injection in one-day-old pups on the same neurobehavioral and histopathological/immunohistochemical endpoints were also investigated. Seven-day-old Gcdh-/- mice presented altered gait, whereas those receiving a GA neonatal administration manifested other sensorimotor deficits, including an abnormal response to negative geotaxis, cliff aversion and righting reflex, and muscle tone impairment. Compared to the WT mice, adult Gcdh-/- mice exhibited motor impairment, evidenced by poor performance in the Rota-rod test. Furthermore, neonatal GA administration provoked long-standing short- and long-term memory impairment in adult Gcdh-/- mice. Regarding the histopathological features, a significant increase in vacuoles and neurodegenerative cells was observed in both the cerebral cortex and striatum of 15- and 60-day-old Gcdh-/- mice and was more pronounced in mice injected with GA. Neuronal loss (decrease of NeuN staining) was also significantly increased in the cerebral cortex and striatum of Gcdh-/- mice, particularly in those neonatally injected with GA. In contrast, immunohistochemistry of MBP, astrocytic proteins GFAP and S100B, and the microglial marker Iba1 was not changed in 60-day-old Gcdh-/- mice, suggesting no myelination disturbance, reactive astrogliosis, and microglia activation, respectively. These data highlight the neurotoxicity of GA and the importance of early treatment aiming to decrease GA accumulation at early stages of development to prevent brain damage and learning/memory disabilities in GA I patients.

Prepubertal Repeated Berberine Supplementation Enhances Cerebrocerebellar Functions by Modulating Neurochemical and Behavioural Changes in Wistar Rats

Antioxidant-rich supplementation plays an essential role in the function of mammals' central nervous system. However, no research has documented the effect of berberine (BER) supplementation on the cerebrocerebellar function of prepubertal rats. The present study was designed to investigate the impact of BER supplementation on neurochemical and behavioural changes in prepubertal male rats. Five groups (90 ± 5 g, n = 7 each) of experimental rats were orally treated with corn oil or different doses of BER (25, 50, 100, and 200 mg/kg bw) from the 28th at 68 post-natal days. On the 69 days of life, animals underwent behavioural assessment in the open field, hanging wire, and negative geotaxis tests. The result revealed that BER administration improved locomotive and motor behaviour by increasing distance travelled, line crossings, average speed, time mobile, and absolute turn angle in open field test and decrease in time to re-orient on an incline plane, a decrease in immobility time relative to the untreated control. Furthermore, BER supplementation increased (p < 0.05) antioxidant enzyme activities such as SOD, CAT, GPx, GSH, and TSH and prevented increases (p < 0.05) in oxidative and inflammatory levels as indicated by decreases in RONS, LPO, XO, carbonyl protein, NO, MPO, and TNF-α compared to the untreated control. BER-treated animals a lessened number of dark-stained Nissl cells compared to the untreated control rats. Our findings revealed that BER minimised neuronal degeneration and lesions, improved animal behaviour, and suppressed oxidative and inflammatory mediators, which may probably occur through its agonistic effect on PPAR-α, PPAR-δ, and PPAR-γ - essential proteins known to resolve inflammation and modulate redox signalling towards antioxidant function.

Evaluation of the protective effect of capric acid on behavioral and biochemical alterations in valproic acid-induced model of autism

AIM AND OBJECTIVE

The purpose of the study is to determine the neuroprotective effect of capric acid on sodium valproate-induced model of autism.

METHODS

In this study, the effect of CA was observed in animals with single dose of valproic acid (600 mg/kg, i. p.) where the disease condition was confirmed by developmental impairment in pups. Behavioral tests that assess anxiety, depression, stereotypical and repetitive behavior, social interaction, learning and memory, and other confounding variables were performed. Subsequently, oxidative stress parameters, pro-inflammatory cytokine levels and mitochondrial complex activities in the selected brain regions were analyzed.

RESULTS

Valproic acid successfully produced autism-like symptoms from post-natal day 7 and also demonstrated impairment in social behavior, learning and memory, and anxiety and depression. Valproic acid was found to produce oxidative stress and neuro-inflammation in the hippocampus, prefrontal cortex, and cerebellum. Treatment with capric acid produced a positive effect on the alterations with maximum effects evident at 400 mg/kg, p. o. through amelioration of behavioral as well as biochemical changes.

CONCLUSION

The current study concluded that capric acid could act as a likely candidate for the treatment and management of autism via significant modulation of neurobehavioral parameters, oxidative stress, mitochondrial dysfunction and inflammatory markers.

Comparative Evaluation of Neuroprotective Activity of Tryptanthrin and Its Oxime in Middle Cerebral Artery Occlusion in Rats

The neuroprotective activity of tryptanthrin and its oxime was compared in male Wistar rats with a model of intraluminal occlusion of the middle cerebral artery. Neurobehavioral tests were performed 4, 24, and 48 h after focal cerebral infarction (FCI) using a modified neurological severity score (mNSS); additionally, the horizontal stability test, the plantar sensitivity test of the fore and hind limbs, holding on the tilted cage top test, and negative geotaxis test were performed. The size of FCI and the severity of brain tissue swelling were examined on day 2 after occlusion. Tryptanthrin and its oxime were administered at a dose of 10 mg/kg intraperitoneally during FCI, then daily for 2 days. In the control group, the mean score of neurological deficit remained at a high level for 2 days. FCI size was 43.8±3.4% of hemisphere area, and the hemisphere volume increased by 18.5±2.0% due to brain tissue swelling and edema. Administration of tryptanthrin and its oxime significantly decreased neurological deficits at all control points and reduced FCI size (by 24.2 and 30.4%, respectively) and brain tissue swelling of the affected hemisphere (by 64.9 and 62.7%, respectively). Therefore, the neuroprotective effect of tryptanthrine and its oxime in the acute period of FCI is largely determined by their anti-inflammatory activity.

Protective role of the ginsenoside Rg1 against methimazole-induced gestational hypothyroidism on reflexive behaviors, conditioned fear and cortical antioxidant levels in mice offspring

Ginsenoside Rg1(Rg1), a monomer of a tetracyclic triterpenoid derivative, possesses diverse medicinal properties attributed to its unique chemical structure and may have beneficial effects on fetal development. This study aimed to investigate the protective effects of prenatal exposure to Rg1 against Methimazole-induced gestational hypothyroidism on reflexive behaviors, conditioned fear, and cortical antioxidant levels in mouse offspring.40 female virgin mice and 12 male NMRI mice were assigned to four groups: group 1 served as the control, group 2 received Methimazole(MMI) at a concentration of 0.02% in their drinking water, group 3 received Rg1(150 mg/kg), and group 4 received both MMI and Rg1.Groups of 2-4 were administered the substances from days 1-9 of gestation. After delivery, pups were selected, and reflexive motor behaviors and conditioned fear were assessed. Additionally, levels of brain tissue catalase(CAT), malondialdehyde(MDA), superoxide dismutase(SOD), and glutathione peroxidase(GPx) levels were measured. Furthermore, postpartum immobility time in the forced swimming test (FST), tail suspension test (TST), and the number of squares crossed in the open field test (OFT)were determined. The results demonstrated that maternal exposure to Rg1 improved ambulation score, hind-limb suspension score, grip strength, front-limb suspension, hind-limb foot angle, negative geotaxis, surface righting, and conditioned fear in hypothyroidism-induced offspring(P<0.05). Rg1 decreased immobility time in the FST, and TST, and increased the number of squares crossed in the OFT in postpartum hypothyroidism-induced mice(P<0.05). Moreover, Rg1 reduced brain tissue MDA levels and increased brain tissue CAT, SOD, and GPx levels in mice and their offspring(P<0.05). These findings indicate that Rg1 mitigated postpartum depression in mice and improved reflexive motor behaviors in their pups.

The Notch1/Hes1 pathway regulates Neuregulin 1/ErbB4 and participates in microglial activation in rats with VPA-induced autism

The core clinical characteristics of autism, which is a neurodevelopmental disease, involve repetitive behavior and impaired social interactions. Studies have shown that the Notch and Neuregulin1 (NRG1) signaling pathways are abnormally activated in autism, but the mechanism by which these two signaling pathways interact to contribute to the progression of autism has not been determined. Our results suggest that the levels of Notch1, Hes1, NRG1, and phosphorylated ErbB4 in the cerebellum (CB), hippocampus (HC), and prefrontal cortex (PFC) were increased in rats with valproic acid (VPA)-induced autism compared to those in the Con group. However, 3, 5-difluorophenyl-L-alanyl-L-2-phenylglycine tert-butyl (DAPT), which is a Notch pathway inhibitor, ameliorated autism-like behavioral abnormalities and decreased the protein levels of NRG1 and phosphorylated ErbB4 in rats with VPA-induced autism; these results demonstrated that the Notch1/Hes1 pathway could participate in the pathogenesis of autism by regulating the NRG1/ErbB4 signaling pathway. Studies have shown that the Notch pathway regulates microglial differentiation and activation during the onset of neurological disorders and that microglia affect autism-like behavior via synaptic pruning. Therefore, we hypothesized that the Notch1/Hes1 pathway could regulate the NRG1/ErbB4 pathway and thus participate in the development of autism by regulating microglial functions. The present study showed that AG1478, which is an ErbB4 inhibitor, ameliorated the autism-like behaviors in a VPA-induced autism rat model, reduced abnormal microglial activation, and decreased NRG1 and Iba-1 colocalization; however, AG1478 did not alter Notch1/Hes1 activity. These results demonstrated that Notch1/Hes1 may participate in the microglial activation in autism by regulating NRG1/ErbB4, revealing a new mechanism underlying the pathogenesis of autism.

Neuroprotective efficacy of hypothermia and Inter-alpha Inhibitor Proteins after hypoxic ischemic brain injury in neonatal rats

Therapeutic hypothermia is the standard of care for hypoxic-ischemic (HI) encephalopathy. Inter-alpha Inhibitor Proteins (IAIPs) attenuate brain injury after HI in neonatal rats. Human (h) IAIPs (60 ​mg/kg) or placebo (PL) were given 15 ​min, 24 and 48 ​h to postnatal (P) day-7 rats after carotid ligation and 8% oxygen for 90 ​min with (30 ​°C) and without (36 ​°C) exposure to hypothermia 1.5 ​h after HI for 3 ​h. Hemispheric volume atrophy (P14) and neurobehavioral tests including righting reflex (P8-P10), small open field (P13-P14), and negative geotaxis (P14) were determined. Hemispheric volume atrophy in males was reduced (P ​< ​0.05) by 41.9% in the normothermic-IAIP and 28.1% in the hypothermic-IAIP compared with the normothermic-PL group, and in females reduced (P ​< ​0.05) by 30.3% in the normothermic-IAIP, 45.7% in hypothermic-PL, and 55.2% in hypothermic-IAIP compared with the normothermic-PL group after HI. Hypothermia improved (P ​< ​0.05) the neuroprotective effects of hIAIPs in females. The neuroprotective efficacy of hIAIPs was comparable to hypothermia in female rats (P ​= ​0.183). Treatment with hIAIPs, hypothermia, and hIAIPs with hypothermia decreased (P ​< ​0.05) the latency to enter the peripheral zone in the small open field test in males. We conclude that hIAIPs provide neuroprotection from HI brain injury that is comparable to the protection by hypothermia, hypothermia increases the effects of hIAIPs in females, and hIAIPs and hypothermia exhibit some sex-related differential effects.

Ameliorating effect of pioglitazone on prenatal valproic acid-induced behavioral and neurobiological abnormalities in autism spectrum disorder in rats

Autism spectrum disorder (ASD) is a neurodevelopment disorder that mainly arises due to abnormalities in different brain regions, resulting in behavioral deficits. Besides its diverse phenotypical features, ASD is associated with complex and varied etiology, presenting challenges in understanding its precise neuro-pathophysiology. Pioglitazone was reported to have a fundamental role in neuroprotection in various other neurological disorders. The present study aimed to investigate the therapeutic potential of pioglitazone in the prenatal valproic acid (VPA)-model of ASD in Wistar rats. Pregnant female Wistar rats received VPA on Embryonic day (E.D12.5) to induce autistic-like-behavioral and neurobiological alterations in their offspring. VPA-exposed rats presented core behavioral symptoms of ASD such as deficits in social interaction, poor spatial and learning behavior, increased anxiety, locomotory and repetitive activity, and decreased exploratory activity. Apart from these, VPA exposure also stimulated neurochemical and histopathological neurodegeneration in various brain regions. We administered three different doses of pioglitazone i.e., 2.5, 5, and 10 mg/kg in rats to assess various parameters. Of all the doses, our study highlighted that 10 mg/kg pioglitazone efficiently attenuated the autistic symptoms along with other neurochemical alterations such as oxidative stress, neuroinflammation, and apoptosis. Moreover, pioglitazone significantly attenuated the neurodegeneration by restoring the neuronal loss in the hippocampus and cerebellum. Taken together, our study suggests that pioglitazone exhibits therapeutic potential in alleviating behavioral abnormalities induced by prenatal VPA exposure in rats. However, further research is needed to fully understand and establish pioglitazone's effectiveness in treating ASD.

The effect of inhibiting hindbrain A2 noradrenergic neurons by 6-Hydroxydopamine on lipopolysaccharide-treated male rats autistic animal model

Autism spectrum disorder (ASD) is a complex neurodevelopmental illness that often emerges in early childhood. The incidence of ASD has shown a notable rise in recent years. ASD is defined by deficits in social communication, and presence of rigid and repetitive behaviors and interests. The underlying mechanisms of ASD remain elusive. Multiple studies have documented the presence of neuroinflammation and increased levels of inflammatory cytokines, specifically, IL-6, TNF, and NF-κB, in various brain regions, including the prefrontal cortex (PFC) and hippocampus in individuals with ASD. Noradrenergic neurons play a crucial role in brain development and the regulation of motor, behavioral, and memory functions. This study sought to examine the impact of intracerebroventricular (icv.) injection of the neurotoxin, 6-hydroxydopamine (6-OHDA), in the caudal dorsal vagal complex A2 neurons on various neuroinflammatory pathways at the hippocampus and PFC in valproic acid (VPA) autistic animal model. This was done in conjunction with an intraperitoneal (i.p.) injection of Lipopolysaccharides (LPS) in animal models with VPA-induced autism. We specifically examined the impact of the caudal fourth ventricle 6-OHDA icv. injection and LPS (i.p.) injection on self-grooming behavior. We measured the mRNA expression of IL-6, TNF-a, and NF-κB using qRT-PCR, and the protein expression of COX-2, GPX-1, p-AMPK, and AMPK using western blot analysis. The self-grooming activity was considerably higher in the combined treatment group (6-OHDA icv. + LPS i.p.) compared to the control group. A substantial increase observed in the expression of IL-6, TNF-α, and NF-κB genes in the PFC of the treatment group that received icv. Administration of 6-OHDA, compared to the control group. The VPA-autism rats that received the combo treatment exhibited a slight increase in the expression level of NF-κB gene in the hippocampus, compared to the control group. At the PFC, we noticed a substantial drop in the expression of the antioxidant protein GPX-1 in the group that received the combo treatment compared to the control group. Our data investigates a novel aspect that the 6-OHDA-induced inhibition of hindbrain A2 neurons could be influencing the neuroinflammatory pathways in the PFC and hippocampus of autistic animal models.

Valproate treatment induces age- and sex-dependent neuronal activity changes according to a patch clamp study

Autism spectrum disorder is a heterogeneous neurodevelopmental disorder characterized by impaired social interactions, restricted, and stereotyped behaviors. The valproic acid model is one of the most recognized and broadly used models in rats to induce core symptoms of this disorder. Comorbidity of epilepsy and autism occurs frequently, due to similar background mechanisms that include the imbalance of excitation and inhibition. In this series of experiments, treatment was performed on rat dams with a single 500 mg/kg dose i.p. valproate injection on embryonic day 12.5. Intracellular whole-cell patch clamp recordings were performed on brain slices prepared from adolescent and adult offspring of both sexes on pyramidal neurons of the medial prefrontal cortex and entorhinal cortex. Current clamp stimulation utilizing conventional current step protocols and dynamic clamp stimulation were applied to assess neuronal excitability. Membrane properties and spiking characteristics of layer II-III pyramidal cells were analyzed in both cortical regions. Significant sex-dependent and age-dependent differences were found in several parameters in the control groups. Considering membrane resistance, rheobase, voltage sag slope, and afterdepolarization slope, we observed notable changes mainly in the female groups. Valproate treatment seemed to enhance these differences and increase network excitability. However, it is possible that compensatory mechanisms took place during the maturation of the network while reaching the age-group of 3 months. Based on the results, the expression of the hyperpolarization-activated cyclic nucleotide-gated channels may be appreciably affected by the valproate treatment, which influences fundamental electrophysiological properties of the neurons such as the voltage sag. Remarkable changes appeared in the prefrontal cortex; however, also the entorhinal cortex shows similar tendencies.

Preventive effects of resveratrol against early-life impairments in the animal model of autism induced by valproic acid

Background

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition characterized by social interaction deficits and repetitive/stereotyped behaviors. Its prevalence is increasing, affecting one in 36 children in the United States. The valproic acid (VPA) induced animal model of ASD is a reliable method for investigating cellular, molecular, and behavioral aspects related to the disorder. Trans-Resveratrol (RSV), a polyphenol with anti-inflammatory and antioxidant effects studied in various diseases, has recently demonstrated the ability to prevent cellular, molecular, sensory, and social deficits in the VPA model. In this study, we examined the effects of prenatal exposure to VPA and the potential preventive effects of RSV on the offspring.

Method

We monitored gestational weight from embryonic day 6.5 until 18.5 and assessed the onset of developmental milestones and morphometric parameters in litters. The generalized estimating equations (GEE) were used to analyze longitudinal data.

Results

Exposure to VPA during rat pregnancy resulted in abnormal weight gain fold-changes on embryonic days 13.5 and 18.5, followed by fewer animals per litter. Additionally, we discovered a positive correlation between weight variation during E15.5-E18.5 and the number of rat pups in the VPA group.

Conclusion

VPA exposure led to slight length deficiencies and delays in the onset of developmental milestones. Interestingly, the prenatal RSV treatment not only prevented most of these delays but also led to the early onset of certain milestones and improved morphometric characteristics in the offspring. In summary, our findings suggest that RSV may have potential as a therapeutic intervention to protect against the negative effects of prenatal VPA exposure, highlighting its importance in future studies of prenatal neurodevelopmental disorders.

Lipopolysaccharide impairs neurodevelopment and induces changes in astroglial reactivity, antioxidant defenses and bioenergetics in the cerebral cortex of neonatal rats

Neonates have an immature immune system, which increases their vulnerability to infectious agents and inflammatory insults. The administration of the immunostimulatory agent lipopolysaccharide (LPS) has been shown to induce the expression of pro-inflammatory cytokines and cause behavior alterations in rodents at different ages. However, the effects of LPS administration during the neonatal period and its consequences during immune system maturation remain to be elucidated. We showed here that a single intraperitoneal administration of LPS in rats on postnatal day (PND) 7 caused early and variable alterations in TNF-α, S100B and GFAP levels in the cerebral cortex, CSF and serum of the animals, indicating long-term induction of neuroinflammation and astroglial reactivity. However, on PND 21, only GFAP levels were increased by LPS. Additionally, LPS induced oxidative stress and altered energy metabolism enzymes in the cerebral cortex on PND 21, and caused neurodevelopment impairment over time. These data suggest that neuroinflammation induction during the neonatal period induces glial reactivity, oxidative stress and bioenergetic disruption that may lead to neurodevelopment impairment and cognitive deficit in adult life.

Phosphodiesterase inhibitor, ibudilast alleviates core behavioral and biochemical deficits in the prenatal valproic acid exposure model of autism spectrum disorder

BACKGROUND

Autism spectrum disorder (ASD) is categorized as a neurodevelopmental disorder, presenting with a variety of aetiological and phenotypical features. Ibudilast is known to produce beneficial effects in several neurological disorders including neuropathic pain, multiple sclerosis, etc. by displaying its neuroprotective and anti-inflammatory properties. Here, in our study, the pharmacological outcome of ibudilast administration was investigated in the prenatal valproic acid (VPA)-model of ASD in Wistar rats.

METHODS

Autistic-like symptoms were induced in Wistar male pups of dams administered with Valproic acid (VPA) on embryonic day 12.5. VPA-exposed male pups were administered with two doses of ibudilast (5 and10 mg/kg) and all the groups were evaluated for behavioral parameters like social interaction, spatial memory/learning, anxiety, locomotor activity, and nociceptive threshold. Further, the possible neuroprotective effect of ibudilast was evaluated by assessing oxidative stress, neuroinflammation (IL-1β, TNF-α, IL-6, IL-10) in the hippocampus, % area of Glial fibrillary acidic protein (GFAP)-positive cells and neuronal damage in the cerebellum.

KEY FINDINGS

Treatment with ibudilast significantly attenuated prenatal VPA exposure associated social interaction and spatial learning/memory deficits, anxiety, hyperactivity, and increased nociceptive threshold, and it decreased oxidative stress markers, pro-inflammatory markers (IL-1β, TNF-α, IL-6), and % area of GFAP-positive cells and restored neuronal damage.

CONCLUSIONS

Ibudilast treatment has restored crucial ASD-related behavioural abnormalities, potentially through neuroprotection. Therefore, benefits of ibudilast administration in animal models of ASD suggest that ibudilast may have therapeutic potential in the treatment of ASD.

Altered offspring neurodevelopment in an L-NAME-induced preeclampsia rat model

Introduction

To investigate the mechanism underlying the increased risk of subsequent neurodevelopmental disorders in children born to mothers with preeclampsia, we evaluated the neurodevelopment of offspring of a preeclampsia rat model induced by the administration of N-nitro-L-arginine methyl ester (L-NAME) and identified unique protein signatures in the offspring cerebrospinal fluid.

Methods

Pregnant rats received an intraperitoneal injection of L-NAME (250 mg/kg/day) during gestational days 15-20 to establish a preeclampsia model. Behavioral experiments (negative geotaxis, open-field, rotarod treadmill, and active avoidance tests), immunohistochemistry [anti-neuronal nuclei (NeuN) staining in the hippocampal dentate gyrus and cerebral cortex on postnatal day 70], and proteome analysis of the cerebrospinal fluid on postnatal day 5 were performed on male offspring.

Results

Offspring of the preeclampsia dam exhibited increased growth restriction at birth (52.5%), but showed postnatal catch-up growth on postnatal day 14. Several behavioral abnormalities including motor development and vestibular function (negative geotaxis test: p < 0.01) in the neonatal period; motor coordination and learning skills (rotarod treadmill test: p = 0.01); and memory skills (active avoidance test: p < 0.01) in the juvenile period were observed. NeuN-positive cells in preeclampsia rats were significantly reduced in both the hippocampal dentate gyrus and cerebral cortex (p < 0.01, p < 0.01, respectively). Among the 1270 proteins in the cerebrospinal fluid identified using liquid chromatography-tandem mass spectrometry, 32 were differentially expressed. Principal component analysis showed that most cerebrospinal fluid samples achieved clear separation between preeclampsia and control rats. Pathway analysis revealed that differentially expressed proteins were associated with endoplasmic reticulum translocation, Rab proteins, and ribosomal proteins, which are involved in various nervous system disorders including autism spectrum disorders, schizophrenia, and Alzheimer's disease.

Conclusion

The offspring of the L-NAME-induced preeclampsia model rats exhibited key features of neurodevelopmental abnormalities on behavioral and pathological examinations similar to humans. We found altered cerebrospinal fluid protein profiling in this preeclampsia rat, and the unique protein signatures related to endoplasmic reticulum translocation, Rab proteins, and ribosomal proteins may be associated with subsequent adverse neurodevelopment in the offspring.

L-2-Hydroxyglutaric Acid Administration to Neonatal Rats Elicits Marked Neurochemical Alterations and Long-Term Neurobehavioral Disabilities Mediated by Oxidative Stress

L-2-Hydroxyglutaric aciduria (L-2-HGA) is an inherited neurometabolic disorder caused by deficient activity of L-2-hydroxyglutarate dehydrogenase. L-2-Hydroxyglutaric acid (L-2-HG) accumulation in the brain and biological fluids is the biochemical hallmark of this disease. Patients present exclusively neurological symptoms and brain abnormalities, particularly in the cerebral cortex, basal ganglia, and cerebellum. Since the pathogenesis of this disorder is still poorly established, we investigated the short-lived effects of an intracerebroventricular injection of L-2-HG to neonatal rats on redox homeostasis in the cerebellum, which is mostly affected in this disorder. We also determined immunohistochemical landmarks of neuronal viability (NeuN), astrogliosis (S100B and GFAP), microglia activation (Iba1), and myelination (MBP and CNPase) in the cerebral cortex and striatum following L-2-HG administration. Finally, the neuromotor development and cognitive abilities were examined. L-2-HG elicited oxidative stress in the cerebellum 6 h after its injection, which was verified by increased reactive oxygen species production, lipid oxidative damage, and altered antioxidant defenses (decreased concentrations of reduced glutathione and increased glutathione peroxidase and superoxide dismutase activities). L-2-HG also decreased the content of NeuN, MBP, and CNPase, and increased S100B, GFAP, and Iba1 in the cerebral cortex and striatum at postnatal days 15 and 75, implying long-standing neuronal loss, demyelination, astrocyte reactivity, and increased inflammatory response, respectively. Finally, L-2-HG administration caused a delay in neuromotor development and a deficit of cognition in adult animals. Importantly, the antioxidant melatonin prevented L-2-HG-induced deleterious neurochemical, immunohistochemical, and behavioral effects, indicating that oxidative stress may be central to the pathogenesis of brain damage in L-2-HGA.

Narrative Review: The Effect of Vitamin A Deficiency on Gut Microbiota and Their Link with Autism Spectrum Disorder

Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders defined by a lack of social behaviors, repetitive behaviors and nonverbal interactions, such as limited eye contact, facial expression, and body gesturing. It is not a single condition, but rather a multi-factorial disorder caused by hereditary and non-genetic risk factors, as well as their interaction. According to several studies, the gut microbiota may have a role in the pathophysiology of autism spectrum disorder. Various studies have found differences in the composition of the gastrointestinal (GI) microbiota in children with ASD compared to unaffected siblings and/or healthy unrelated controls. The processes that relate the gut microbiota to brain dysfunctions (the gut-brain axis) in ASD are yet to be fully understood. However, the differences in the gastrointestinal composition might be due to vitamin A deficiency because vitamin A (VA) plays a role in the regulation of the intestinal microbiota. This narrative review discusses the impact of vitamin A deficiency on the gut microbiota composition and tries to understand how this may contribute for the development and severity of ASD.

The effects of acamprosate on maternal and neonatal outcomes in a mouse model of alcohol use disorders

BACKGROUND

Despite the teratogenic effects of alcohol, little is known about the safety of pharmacotherapies such as acamprosate for the treatment of alcohol use disorders in pregnancy. The aims of this study were to investigate, in a mouse model, the effects of maternally administered acamprosate on maternal and neonatal health, offspring neurodevelopment and behaviour, as well as examine whether acamprosate reduces the neurological harm associated with alcohol consumption in pregnancy.

METHODS

Dams were randomly allocated to one of four treatment groups: (i) control (water), (ii) acamprosate (1.6 g/L), (iii) alcohol (5% v/v) or (iv) acamprosate and alcohol (1.6 g/L; 5% v/v ethanol) and exposed from 2-weeks pre-pregnancy until postpartum day 7. Gestational outcomes including litter size and sex ratio were assessed, in addition to early-life markers of neurodevelopment. At 8 weeks of age, motor coordination, anxiety, locomotion, and memory of the adult offspring were also examined.

RESULTS

Exposure to acamprosate did not affect maternal and birth outcomes (mating success, gestational weight gain, litter size, sex ratio), neonatal outcomes (head and body length, postnatal weight) or neurodevelopmental markers (righting reflex and negative geotaxis). Acamprosate exposure did not affect offspring motor control, locomotion or anxiety, however the effects on short-term memory remain uncertain. Prenatal alcohol exposed offspring exhibited various alterations, such as lower postnatal weight, smaller head (p = 0.04) and body lengths (p = 0.046) at postnatal day 70 (males only), increased negative geotaxis speed (p = 0.03), an increased time spent in the inner zone of the open field (p = 0.02). Acamprosate mitigated the effects of alcohol for negative geotaxis at postnatal day 7 (p = 0.01) and female offspring weight at postnatal day 70 (p = 0.03).

CONCLUSIONS

Overall, we show that prenatal acamprosate exposure was not associated with poor maternal or neonatal health outcomes or impaired neurodevelopment and behaviour. However, acamprosate's effects on short-term memory remain uncertain. We present preliminary evidence to suggest acamprosate displayed some neuroprotective effects against damage caused by in utero alcohol exposure.

Methimazole-induced gestational hypothyroidism affects the offspring development and differently impairs the conditioned fear in male and female adulthood rodents

Gestational hypothyroidism is a prevalent disorder in pregnant women and also impairs fetal development with relevant outcomes. One of the outcomes of greatest interest has been rodent fear- and anxiety-like behavior. However, the relationship between maternal hypothyroidism and onset of conditioned fear-related responses in offspring remains controversial. Here, we used a well-validated methimazole-induced gestational hypothyroidism to investigate the behavioral consequences in offspring. Dams were treated with methimazole at 0.02% in drinking water up to gestational Day 9. Maternal body weights and maternal behavior were evaluated, and the puppies ware analyzed for weight gain and physical/behavioral development and assigned for the open field and fear conditioning test. Methimazole-induced gestational hypothyroidism induced loss in maternal and litter weight, increases in maternal behavior, and impairs in offspring developmental landmarks in both male and female rodents. Only male offspring enhanced responsiveness to conditioned fear-like behavior in adulthood.

Effect of Hypoxic-Ischemic Brain Injury in Neonatal Rats on Behavioral Parameters and Expression of CDK8 in the Brain Tissue

Behavioral changes in newborn 3-day-old rats (n=44) with modeled hypoxic-ischemic brain injury (HIBI) were observed, and the expression of CDK8 in brain tissues was detected to clarify the significance of CDK8. In 30 min, 3 h, and 3 days after HIBI, the left (ischemic) hemisphere was taken for examination. In 3 days after HIBI, the rat pups were examined in the behavioral tests. In rat pups with HIBI, changes of CDK8 expression were detected by Western blotting and real-time PCR and changes in the righting reflex and forelimb grip strength test (p<0.05) were revealed in comparison with sham-operated animals. The expression of CDK8 increased 30 min after HIBI and decreased in 3 h and 3 days. Hypoxia and ischemia of the left brain may affect locomotion, but not sensation. Since CDK8 is involved in the immune response after cerebral hypoxia and ischemia, this kinase can be used as an early diagnostic index.

Granulocyte Colony-Stimulating Factor Improved Core Symptoms of Autism Spectrum Disorder via Modulating Glutamatergic Receptors in the Prefrontal Cortex and Hippocampus of Rat Brains

Chronic neuroinflammation-induced anomalous glutamate receptor activation has been identified as one of the important factors in the pathogenesis of autism spectrum disorder (ASD). Thus, the current study was designed to elucidate the neuroprotective effect of the granulocyte colony-stimulating factor (G-CSF), a haemopoietic growth factor, an anti-inflammatory, and a neuroprotectant to decipher the underlying mechanism(s) in the valproic acid (VPA)-induced experimental model of ASD. Experimentally, the ASD rat model was induced by a single dose of VPA (600 mg/kg; i.p.) on gestation day 12.5 to the pregnant female rats. After birth, pups were treated with vehicle, normal saline 0.9% i.p., risperidone (2.5 mg/kg; i.p.), and G-CSF (10, 35, and 70 μg/kg; i.p.) from postnatal day (PND) 23 to 43. All the groups were subjected to various developmental and behavior tests from birth. The rats were sacrificed on PND 55, and their brain was excised and processed for biochemical parameters (oxidative stress, inflammatory markers, BDNF), histological examination (H&E, Nissl staining), NMDA, and AMPA receptor expression by immunohistochemistry, western blot, and real-time polymerase chain reaction evaluation. Also, the possible interaction of the G-CSF with NMDA and AMPA receptors was evaluated using the in-silico method. The results of the study showed that in VPA-exposed rats, postnatal treatment of G-CSF rescued all the behavioral abnormalities, oxidative stress, and inflammatory parameters in a dose-dependent manner while risperidone did not show any significant results. The in-silico analysis showed the direct interaction of G-CSF with NMDA and AMPA receptors. The upregulated expression of NMDA and AMPA both in the prefrontal cortex as well as hippocampus was alleviated by G-CSF thereby validating its anti-inflammatory and excitoprotective properties. Thus, G-CSF demonstrated neuroprotection against the core symptoms of autism in the VPA-induced rodent model, making it a potential candidate for the treatment of ASD.

Probing Caffeine Administration as a Medical Management for Hydrocephalus: An Experimental Study

BACKGROUND

Hydrocephalus is currently managed by cerebrospinal fluid diversion from the cerebral ventricles to other body sites, but this is complicated by obstruction and infection in young infants, thus adding to morbidity and mortality. Studies have reported caffeine to be a pleiotropic neuroprotective drug in the developing brain due to its antioxidant, anti-inflammatory, and antiapoptotic properties, with improved white matter microstructural development. In this study, we investigate the use of caffeine administration as a possible means of pharmacological management for hydrocephalus.

METHODS

A total of 76 three-day-old mice pups from 10 dams were divided into four groups: hydrocephalus was induced in the pups in two groups by intracisternal injection of kaolin suspension, and their dams were given either caffeine (50 mg/kg by gavage) or water daily for 21 days; the dams in the other 2 (non-hydrocephalic) groups similarly had either caffeine or water; the pups received caffeine administered via lactation. Developmental neurobehavioral tests were performed until day 21, when the pups were sacrificed. Their brains were removed and processed for Cresyl and Golgi staining; both quantitative and qualitative analyses were then carried out.

RESULTS

Improved developmental motor activities and reflexes were observed in the hydrocephalus + caffeine-treated pups. Caffeine administration was associated with reduced cell death and increased dendritic arborization of the neurons in the sensorimotor cortex and striatum of hydrocephalic mice pups.

CONCLUSION

Caffeine administration appears to have promise as an adjunct in hydrocephalus management, and its use needs to be further explored.

Neuromotor Development in the Shank3 Mouse Model of Autism Spectrum Disorder

Although autism spectrum disorder (ASD) is mainly characterized by developmental delay in social and communication skills, it has been shown that neuromotor deficits are an early component of ASD. The neuromotor development of B6.129-Shank3tm2Gfng/J (Shank3B−/−) mice as an animal model of autism has not been analyzed yet. The aim of this study was to compare the early neuromotor development of Shank3B−/− to wild-type mice. The mice underwent a multitude of neurodevelopmental tests and observations from postnatal day 1 (PND = 1) to weaning. Shank3B−/− mice opened their eyes later than their wild-type litter mates (p < 0.01). Shank3B−/− mice were also slower in the negative geotaxis test from PND = 13 to PND = 16 (p < 0.001) in both sexes. The results of this study indicate neurodevelopmental deficits in Shank3B−/− mice. The test is partially dependent on truncal motor control, and these lines of evidence suggest a phenotype of developmental hypotonia, which corresponds with the phenotypes seen in patients with Phelan-McDermid Syndrome. There was no observable effect of sex in any of the tests. There were no observed differences in upper and lower incisor eruption, ear unfolding, air righting, surface righting and ear twitch reflexes. Further studies should prove whether the delay in neuromotor development is linked to social or communication deficits, and thus, whether it may serve as an early indicator of autistic-like phenotype in mice.

Addition of Prebiotics to the Ketogenic Diet Improves Metabolic Profile but Does Not Affect Seizures in a Rodent Model of Infantile Spasms Syndrome

The ketogenic diet (KD) is an effective treatment for infantile spasms syndrome (IS). However, the KD has implications for somatic growth, development, and the gut microbiota. The impact of incorporating a prebiotic fiber (PRE, oligofructose-enriched inulin, 0.8 g/dL) into a KD diet on spasms, developmental milestones, fecal gut microbiota, metabolites, and hippocampal mitochondrial metabolism were examined. Following IS induction, animals were randomized to KD or KD + PRE diets. A third group without IS and suckled by dams was included as a normally developing reference group (R). PRE inclusion decreased ketones and increased circulating glucose levels but had no impact on spasms. In the liver, PRE increased triglyceride concentrations, decreased carnitine levels, and downregulated genes encoding enzymes responsible for ketogenesis. In the hippocampus, PRE increased glutathione levels but did not affect the maximal respiratory capacity of mitochondria. Analysis of the gut microbiota showed that KD + PRE increased microbial richness and the relative abundance of Bifidobacterium pseudolongum and Lactobacillus johnsonii. No differences in developmental milestones (i.e., surface righting, negative geotaxis, and open field behavior) were observed between KD and KD + PRE, except for ultrasonic vocalizations that were more frequent in KD + PRE. In summary, PRE did not impact spasms or developmental outcomes, but was effective in improving both metabolic parameters and gut microbiota diversity.

Head-to-Head Study of Developmental Neurotoxicity and Resultant Phenotype in Rats: α-Hexabromocyclododecane versus Valproic Acid, a Recognized Model of Reference for Autism Spectrum Disorders

Evidence is now growing that exposure to environmental pollutants during the critical early-life period of brain development may contribute to the emergence of Autism Spectrum Disorders (ASD). This study seeks to compare the developmental neurotoxicity of the α-isomer of hexabromocyclododecane (α-HBCDD), a persistent brominated flame retardant, to the valproic acid (VPA) model of ASD in rodents. Pregnant Wistar rats were divided into three groups: control, α-HBCDD (100 ng/kg/day p.o., GD0-PND21) and VPA (600 mg/kg i.p., GD12). Male offspring were tested for their neuromotor development from PND2-21. At PND21, brain functionality was assessed by measuring cytochrome oxidase activity (CO). Modifications in neuroglia and synaptic plasticity were evaluated in the cortex. Similar subtle behavioural changes related to neuromotor maturation and noise reaction were observed in both treated groups. At PND21, a reduction in CO activity was measured in the VPA group only, in specific areas including auditory nuclei, visual cortex, cingulate and frontal cortices. At the same age, α-HBCDD pointed out significant overexpression of cortical markers of synaptic plasticity while both treated groups showed a significant under expression of astrocyte proteins (S100-β and GFAP). Early-life exposure to a low dose of α-HBCDD may trigger neurobehavioural alterations in line with ASD.

Alterations of the Hippocampal Networks in Valproic Acid-Induced Rat Autism Model

Autism Spectrum Disorder (ASD) is one of the most frequently diagnosed neurodevelopmental disorders, characterized among others by impairments in social interactions and repetitive behavior. According to one of the leading hypotheses about its origin, ASD is caused by the imbalance of excitatory and inhibitory circuit activity. ASD-related morphological and functional changes can be observed in several brain regions i.e., in the prefrontal cortex and the hippocampus. It is well-established that prenatal valproic-acid (VPA) exposure of rats on day 12.5 leads to neurodevelopmental alterations with autism-like clinical and behavioral symptoms. The aim of this study was to investigate potential changes in the excitability of neuronal networks and individual neurons of the hippocampus elicited by prenatal VPA treatment. As there are marked sex differences in ASD, offspring of both sexes were systematically tested, using two different age groups, to elucidate eventual differences in neurodevelopment after VPA treatment. Excitatory connections and long-term synaptic plasticity as well as intrinsic excitability of CA1 pyramidal cells were examined. Pregnant female Wistar rats received saline or 500 mg/kg VPA i. p. on gestation day 12.5. Brain slices of 6-week-old and 3-month-old offspring were investigated using extra- and intracellular electrophysiological techniques. Field potential- and whole-cell patch clamp recordings were carried out to measure network excitability and single cell activity in the CA1 region hippocampus. Enhanced excitability of hippocampal networks was detected in the 6-week-old VPA-treated male rats; however, this change could not be observed in 3-month-old males. Intrinsic excitability of single neurons, however, was increased in 3-month-old males. In 6-week-old treated females, the most prominent effect of VPA was an increase in voltage sag, to a similar degree to the neurons of the older age group. In 3-month-old females, a network excitability increase could be demonstrated, in a lesser degree than in younger males. It can be concluded, that VPA treatment had diverse effects on hippocampal excitability depending on the sex and the age of the animals. We found that certain alterations manifested in 6-week-old rats were compensated later, on the other hand, other changes persisted until the age of 3 months.

Quantification of Behavioral Deficits in Developing Mice With Dystonic Behaviors

Converging evidence from structural imaging studies in patients, the function of dystonia-causing genes, and the comorbidity of neuronal and behavioral defects all suggest that pediatric-onset dystonia is a neurodevelopmental disorder. However, to fully appreciate the contribution of altered development to dystonia, a mechanistic understanding of how networks become dysfunctional is required for early-onset dystonia. One current hurdle is that many dystonia animal models are ideally suited for studying adult phenotypes, as the neurodevelopmental features can be subtle or are complicated by broad developmental deficits. Furthermore, most assays that are used to measure dystonia are not suited for developing postnatal mice. Here, we characterize the early-onset dystonia in Ptf1a ^Cre ;Vglut2 ^fl/fl mice, which is caused by the absence of neurotransmission from inferior olive neurons onto cerebellar Purkinje cells. We investigate motor control with two paradigms that examine how altered neural function impacts key neurodevelopmental milestones seen in postnatal pups (postnatal day 7-11). We find that Ptf1a ^Cre ;Vglut2 ^fl/fl mice have poor performance on the negative geotaxis assay and the surface righting reflex. Interestingly, we also find that Ptf1a ^Cre ;Vglut2 ^fl/fl mice make fewer ultrasonic calls when socially isolated from their nests. Ultrasonic calls are often impaired in rodent models of autism spectrum disorders, a condition that can be comorbid with dystonia. Together, we show that these assays can serve as useful quantitative tools for investigating how neural dysfunction during development influences neonatal behaviors in a dystonia mouse model. Our data implicate a shared cerebellar circuit mechanism underlying dystonia-related motor signs and social impairments in mice.

Exposure of pregnant rats to stress and/or sertraline: Side effects on maternal health and neurobehavioral development of male offspring

AIMS

Sertraline (SE) is one of the most prescribed medications for treating gestational depression, anxiety and stress. However, little is known about its effects on nervous-system development in offspring. Therefore, this study investigated the somatic, reflex and neurobehavioral development of rats exposed to SE during pregnancy, associated or not with stress.

MAIN METHODS

Pregnant Wistar rats were assigned to the following groups (n = 10-8 rats/group): CO - control animals administered filtered water by gavage; SE - animals administered 20 mg/kg SE by gavage; ST - animals subjected to restraining stress and administered filtered water; ST/SE - animals subjected to restraining stress and administered 20 mg/kg SE. The treatment was administered between gestational days (GD) 13 to 20. Somatic and reflex developments were investigated in the male offspring from postnatal day (PND) 1 to 21. The elevated plus maze was performed on PND 25 and 80. The open field and light/dark box test were performed on PND 90 and 100, respectively.

KEY FINDINGS

Body weight reduction and vaginal bleeding were observed in pregnant rats exposed to SE. The male offspring of the SE group showed delay in incisor eruption, fur development and negative geotaxis. In addition, the SE group was less exploratory (anxious personality) compared to the CO and ST groups.

SIGNIFICANCE

The results obtained in the present study demonstrate that sertraline not only impairs maternal health, but also, associated or not with stress, can compromise the somatic, reflex and neurobehavioral development of male rats.

Inhibition of the ERK1/2 Phosphorylation by Dextromethorphan Protects against Core Autistic Symptoms in VPA Induced Autistic Rats: In Silico and in Vivo Drug Repurposition Study

The imbalance between excitatory and inhibitory neurotransmitters is explicitly related to the pathophysiology of autism spectrum disorder (ASD). The role of an NMDA receptor antagonist, dextromethorphan, was studied in ameliorating the ASD-like symptoms by regulating the excitatory and inhibitory imbalance using the valproic acid (VPA) model of ASD. Female Wistar rats were administered VPA [600 mg/kg on embryonic day ED-12.5] through intraperitoneal (ip) injection to induce ASD in pups. Autistic pups were then given dextromethorphan (10, 15, and 30 mg/kg; ip) and risperidone (2.5 mg/kg; ip) from PND 23 to 43 in different groups. Behavioral tests (three chamber sociability, self-grooming, Morris water maze, elevated plus maze, open field, rotarod, grip strength), oxidative stress and inflammatory markers, histological evaluation (H&E, Nissil staining), and NMDA and ERK1/2 expression by immunohistochemistry and RT-PCR were done. The in silico modeling of dextromethorphan against PPDA, TCN-201, MK-22, EVT-101 on NMDA receptors was also performed. Dextromethorphan (30 mg/kg) rescued the impaired behavioral patterns including social excitability, hyperactivity, repetitive and restricted behaviors as well as mitigation of the memory and motor coordination. The levels of various oxidative stress markers (GSH, SOD, catalase, MDA) and inflammatory markers (IL-1β, IL-6, IL-10, TNF-α) were ameliorated by different doses of dextromethorphan. It also reduced the neuronal injury score and rescued the overly expressed pERK1/2 and NMDA signaling in both the prefrontal cortex and hippocampus of the autistic pups. In silico results showed favorable binding of dextromethorphan against TCN-201 and MK-22 binding sites. The present study provided experimental evidence for the potential therapeutic role of dextromethorphan in attenuating autism symptomatology in the ASD model of rats. Thus, modulation of the glutamatergic signaling can be a potential target for ASD treatment.

Optimization of behavioral testing in a long-term rat model of hypoxic ischemic brain injury

BACKGROUND

Hypoxic ischemic (HI) brain injury is a significant cause of childhood neurological deficits. Preclinical rodent models are often used to study these deficits; however, no preclinical study has determined which behavioral tests are most appropriate for long-term follow up after neonatal HI.

METHODS

HI brain injury was induced in postnatal day (PND) 10 rat pups using the Rice-Vannucci method of unilateral carotid artery ligation. Rats underwent long-term behavioral testing to assess motor and cognitive outcomes between PND11-50. Behavioral scores were transformed into Z-scores and combined to create composite behavioral scores.

RESULTS

HI rats showed a significant deficit in three out of eight behavioral tests: negative geotaxis analysis, the cylinder test and the novel object recognition test. These individual test outcomes were transformed into Z-scores and combined to create a composite Z-score. This composite z-score showed that HI rats had a significantly increased behavioral burden over the course of the experiment.

CONCLUSION

In this study we have identified tests that highlight specific cognitive and motor deficits in a rat model of neonatal HI. Due to the high variability in this model of neonatal HI brain injury, significant impairment is not always observed in individual behavioral tests, but by combining outcomes from these individual tests, long-term behavioral burden can be measured.

Curcumin Prevents Cerebellar Hypoplasia and Restores the Behavior in Hyperbilirubinemic Gunn Rat by a Pleiotropic Effect on the Molecular Effectors of Brain Damage

Bilirubin toxicity to the central nervous system (CNS) is responsible for severe and permanent neurologic damage, resulting in hearing loss, cognitive, and movement impairment. Timely and effective management of severe neonatal hyperbilirubinemia by phototherapy or exchange transfusion is crucial for avoiding permanent neurological consequences, but these therapies are not always possible, particularly in low-income countries. To explore alternative options, we investigated a pharmaceutical approach focused on protecting the CNS from pigment toxicity, independently from serum bilirubin level. To this goal, we tested the ability of curcumin, a nutraceutical already used with relevant results in animal models as well as in clinics in other diseases, in the Gunn rat, the spontaneous model of neonatal hyperbilirubinemia. Curcumin treatment fully abolished the landmark cerebellar hypoplasia of Gunn rat, restoring the histological features, and reverting the behavioral abnormalities present in the hyperbilirubinemic rat. The protection was mediated by a multi-target action on the main bilirubin-induced pathological mechanism ongoing CNS damage (inflammation, redox imbalance, and glutamate neurotoxicity). If confirmed by independent studies, the result suggests the potential of curcumin as an alternative/complementary approach to bilirubin-induced brain damage in the clinical scenario.

Kolaviron ameliorates behavioural deficit and injury to striatal dopaminergic terminals via modulation of oxidative burden, DJ-1 depletion and CD45R+ cells infiltration in MPTP-model of Parkinson's disease

Parkinson's disease (PD) is the second most common neurodegenerative disease. Currently, the precise pathogenic detail of PD is not entirely clear and first line therapeutics fail to attenuate the progress of the disease. In this study, we examined the neuroprotective effect of kolaviron, a natural antioxidant and anti-inflammatory biflavonoid from Garcinia kola seed, on behavioural impairment, neurodegeneration, oxidative stress and neuroinflammation in an acute MPTP-induced PD model. Kolaviron mitigated the frequently interrupted MPTP-associated hyperkinesia, inefficient gait, immobility, inability to pay attention to sizable holes on walking path, habitual clockwise rotations characterized with minimal diversion of movements and impaired balance. Also, kolaviron suppressed MPTP-mediated striatal oxidative stress, depletion as well as degeneration of dopaminergic terminals, reduced DJ-1 secretion and upregulated expression of caspase-3. Kolaviron facilitated cytoprotective antioxidant response and prevented MPTP-mediated neuroinflammation by blocking striatal infiltration of peripheral CD45R positive cells. Additionally, kolaviron reversed MPTP-induced inhibition of acetylcholinesterase activity. Together, our study provides evidence that the neuroprotective capacity of kolaviron to modulate striatal degeneration, behavioural impairment, antioxidant/redox imbalance and neuroinflammation implicated in the pathogenesis of PD may involve upregulation of DJ-1 secretion and inhibition of CD45R cells infiltration. Our data recommend kolaviron as a possible neuroprotective strategy in the management of Parkinson's disease and the associated behavioural complications, albeit the identity of MPTP-associated striatal CD45R infiltrate needs to be further characterized.