Does caffeine therapy improve cognitive impairments in valproic acid rat model of autism?

Effects of hyperbaric oxygen therapy on autistic behaviors and GRIN2B gene expression in valproic acid-exposed rats

Introduction

Autism is a complex neurodevelopmental condition characterized by deficits in social interaction, communication, and restricted repetitive behaviors. Hyperbaric oxygen therapy (HBOT) has emerged as a potential treatment for autism, although its effects on behavior and gene expression are not well understood. The GRIN2B gene, known for its involvement in encoding a glutamate receptor subunit crucial for neuron communication and associated with autism, was a focus of this study.

Methods

Using a rat model induced by prenatal exposure to valproic acid, we examined the impact of HBOT on autism-like behaviors and GRIN2B gene expression. Male Wistar rats were categorized into four groups: control, VPA (valproic acid-exposed), VPA+HBOT [2 atmosphere absolute (ATA)], and VPA+HBOT (2.5 ATA). The rats underwent several behavioral tests to assess social behavior, anxiety, stereotype and exploratory behaviors, and learning. Following the behavioral tests, the HBOT groups received 15 sessions of HBOT at pressures of 2 and 2.5 (ATA), and their behaviors were re-evaluated. Subsequently, real-time PCR was employed to measure GRIN2B gene expression in the frontal lobe.

Results

Our results indicated that HBOT significantly increased social interaction and exploratory behaviors in VPA-exposed rats, alongside elevated GRIN2B gene expression in their frontal lobe.

Discussion

Our findings imply that HBOT might have a potential role in ameliorating autism-related behaviors in the VPA rat model of autism through potential modulation of GRIN2B gene expression. However, additional research is essential to fully comprehend the underlying mechanisms and refine the HBOT protocol for optimizing its effectiveness in improving autism-related symptoms.

Effects of music on cognitive behavioral impairments in both sex of adult rats exposed prenatally to valproic acid

BACKGROUND

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by impairment in reciprocal social interactions, deficits in communication, and restrictive and repetitive behaviors and interests. In previous studies, music has been identified as an intervention therapy for children with ASD.

OBJECTIVES

The present study evaluated the effects of music on cognitive behavioral impairments in both sexes of adult rats exposed prenatally to Valproic acid.

METHODS

For induction of autism, pregnant female rats were pretreated with either saline or VPA (600 mg/kg.i.p.) at gestational day (GD) 12.5. Male and female offspring were divided into Saline.Non-Music, VPA.Non-Music, Saline.Music, and VPA.Music groups. The adult rats in the music groups were exposed to Mozart's piano sonata K.448 for 30 days (4 h/day), from postnatal day (PND) 60 to 90. Social interaction and Morris water maze (MWM) tasks were tested at PND 90.

RESULTS

Our results revealed that prenatal exposure to VPA decreased sociability and social memory performance in both sexes of adult rats. Moreover, prenatal exposure to VPA created learning and memory impairments in both sexes of adult rats in the MWM task. Music intervention improved sociability in both sexes of VPA-exposed rats and social memory in both sexes of VPA-exposed rats, especially in females. Furthermore, our results revealed that music ameliorated learning impairments in VPA-exposed female rats in the MWM task. In addition, music improved spatial memory impairments in VPA-exposed rats of both sexes, especially in females, which needs more investigation in molecular and histological fields in future studies.

CONCLUSION

Music intervention improved sociability and social memory in adult VPA-exposed rats, especially in female animals. Furthermore, music improved memory impairments in VPA-exposed rats of both sexes. It seems that music had a better influence on female rats. However, future studies need more investigations in molecular and histological fields.

Three Decades of Valproate: A Current Model for Studying Autism Spectrum Disorder

Autism Spectrum Disorder (ASD) is a neurodevelopmental disorder with increased prevalence and incidence in recent decades. Its etiology remains largely unclear, but it seems to involve a strong genetic component and environmental factors that, in turn, induce epigenetic changes during embryonic and postnatal brain development. In recent decades, clinical studies have shown that inutero exposure to valproic acid (VPA), a commonly prescribed antiepileptic drug, is an environmental factor associated with an increased risk of ASD. Subsequently, prenatal VPA exposure in rodents has been established as a reliable translational model to study the pathophysiology of ASD, which has helped demonstrate neurobiological changes in rodents, non-human primates, and brain organoids from human pluripotent stem cells. This evidence supports the notion that prenatal VPA exposure is a valid and current model to replicate an idiopathic ASD-like disorder in experimental animals. This review summarizes and describes the current features reported with this animal model of autism and the main neurobiological findings and correlates that help elucidate the pathophysiology of ASD. Finally, we discuss the general framework of the VPA model in comparison to other environmental and genetic ASD models.

Myrtenol Inhalation Mitigates Asthma-Induced Cognitive Impairments: an Electrophysiological, Behavioral, Histological, and Molecular Study

Asthma is an inflammatory disorder with significant health problems. It generally affects the lungs but can also impact brain performance via several mechanisms. Some investigations have proposed that asthma impairs cognition. This study assessed the impacts of myrtenol as a monoterpene on cognitive disorders following asthma at behavioral, molecular, and synaptic levels. Asthma was induced by injection and inhalation of ovalbumin (OVA). Male Wistar rats were allocated to five groups: control, asthma, asthma/vehicle, asthma/myrtenol, and asthma/budesonide. Myrtenol (8 mg/kg) or budesonide (160 μg/kg) was administered through inhalation once a day for 1 week, and at the end of the inhalation period, behavioral tests (MWM and Open Field), field potential recording, hippocampal brain-derived neurotrophic factor (BDNF), IL1β (ELISA), and NFκB measurement (Western blot) were performed to evaluate cognitive performance. Moreover, H&E (hematoxylin and eosin) staining was used for hippocampus histological evaluation. Myrtenol improved spatial learning, memory, LTP (long-term potentiation) impairments, and anxiety-like behaviors following asthma. Myrtenol inhalation increased the BDNF level and decreased the IL1β level and NFκB expression in the hippocampus of the asthmatic rats. The neuronal damage in the hippocampus following allergic asthma was alleviated via myrtenol administration. Myrtenol, as an herbal extract, protects the hippocampus from asthma consequences. Our observations revealed that myrtenol can improve spatial learning, memory, synaptic plasticity impairments, and anxiety-like behaviors following asthma. We believe that these ameliorating effects of myrtenol can be attributed to inflammation suppression and increased BDNF in the hippocampus.

The Role of Inhaled Estradiol and Myrtenol, Alone and in Combination, in Modulating Behavioral and Functional Outcomes Following Traumatic Experimental Brain Injury: Hemodynamic, Molecular, Histological and Behavioral Study

BACKGROUND

Traumatic brain injury (TBI) is an important and growing cause of disability worldwide, and its cognitive consequences may be particularly significant. This study assessed the neuroprotective impacts of estradiol (E2), myrtenol (Myr), and the combination of the two on the neurological outcome, hemodynamic parameters, learning and memory, brain-derived neurotrophic factor (BDNF) level, phosphoinositide 3-kinases (PI3K/AKT) signaling, and inflammatory and oxidative factors in the hippocampus after TBI.

METHODS

Eighty-four adult male Wistar rats were randomly divided into 12 groups with seven rats in each (six groups to measure intracranial pressure, cerebral perfusion pressure, brain water content, and veterinary coma scale, and six groups for behavioral and molecular studies): sham, TBI, TBI/vehicle, TBI/Myr, TBI/E2, and TBI/Myr + E2 (Myr 50 mg/kg and E2 33.3 μg/kg via inhalation for 30 min after TBI induction). Brain injury was induced by using Marmarou's method. Briefly, a 300-g weight was dropped down from a 2-m height through a free-falling tube onto the head of the anesthetized animals.

RESULTS

Veterinary coma scale, learning and memory, brain water content, intracranial pressure, and cerebral perfusion pressure were impaired following TBI, and inflammation and oxidative stress were raised in the hippocampus after TBI. The BDNF level and PI3K/AKT signaling were impaired due to TBI. Inhalation of Myr and E2 had protective effects against all negative consequences of TBI by decreasing brain edema and the hippocampal content of inflammatory and oxidant factors and also by improving BDNF and PI3K/AKT in the hippocampus. Based on these data, there were no differences between alone and combination administrations.

CONCLUSIONS

Our results propose that Myr and E2 have neuroprotective effects on cognition impairments due to TBI.

Effects of voluntary, and forced exercises on neurotrophic factors and cognitive function in animal models of Parkinson's disease

BACKGROUND

Parkinson's disease (PD) is one of the most common neurodegenerative diseases in the elderly. Cognitive dysfunction represents a common and challenging non-motor symptom for people with Parkinson's disease. The number of neurotrophic proteins in the brain is critical in neurodegenerative diseases such as Parkinson's. This research aims to compare the effects of two types of exercise, forced and voluntary, on spatial memory and learning and neurochemical factors (CDNF and BDNF).

METHODS

In this research, 60 male rats were randomly divided into six groups (n = 10): the control (CTL) group without exercise, the Parkinson's groups without and with forced (FE) and voluntary (VE) exercises, and the sham groups (with voluntary and forced exercise). The animals in the forced exercise group were placed on the treadmill for four weeks (five days a week). At the same time, voluntary exercise training groups were placed in a special cage equipped with a rotating wheel. At the end of 4 weeks, learning and spatial memory were evaluated with the Morris water maze test. BDNF and CDNF protein levels in the hippocampus were measured by the ELISA method.

RESULTS

The results showed that although the PD group without exercise was at a significantly lower level than other groups in terms of cognitive function and neurochemical factors, both types of exercise, could improve these problems.

CONCLUSION

According to our results, 4 weeks of voluntary and forced exercises were all found to reverse the cognitive impairments of PD rats.

Investigating the effects of Citrullus colocynthis on cognitive performance and anxiety-like behaviors in STZ-induced diabetic rats

Background: Diabetes can impair cognitive performance and lead to dementia. Patients with type 1 diabetes mellitus (T1DM) are reported with different levels of cognitive dysfunctions in various cognitive domains ranging from general intellectual testing to specific deficits with visuospatial abilities, motor speed, writing, attention, reading, and psychomotor efficiency. The present study aimed to investigate the effect of Citrullus colocynthis on cognitive functions.Methods: A total of 42 male Wistar rats (3-4  months old and weighing 200-250  g) were tested in the current study. Rats were randomly allocated into 3 groups of control, Diabetes, and Diabetes + Drug. The diabetic rats received Citrullus colocynthis extraction orally. The behavioral tests included the open field, elevated plus maze (EPM), novel object recognition (NOR), passive avoidance tests, and Morris Water Maze (MWM) tests. Data were analyzed using student and paired t-tests via SPSS software version 16.Results: Our results showed the protective effects of Citrullus colocynthis administration against cognitive impairments. This is followed by STZ-induced diabetes in the MWM, novel object recognition, and passive avoidance tasks. Also, it was found that Citrullus colocynthis improved anxiety in diabetic rats.Conclusion According to the findings of this study, the administration of 200  mg/kg C. colocynthis once per day for 40  days can lead to ameliorated cognitive impairments and antidiabetic effects such as increasing body weight and decreasing FBS.

High-Intensity Interval Training Ameliorates Molecular Changes in the Hippocampus of Male Rats with the Diabetic Brain: the Role of Adiponectin

Alzheimer's disease (AD) is closely related to type 2 diabetes (T2D). This study investigated the impact of high-intensity interval training (HIIT) on diabetes-induced disturbances in AD-related factors (including AMP-activated protein kinase (AMPK), glycogen synthase kinase-3β (GSK3β), and tau protein) in the hippocampus, with the main focus on adiponectin signaling.In total, 28 male Wistar rats at the age of 8 weeks were randomly assigned to four groups (n = 7 in each group): control (Con), type 2 diabetes (T2D), HIIT (Ex), and type 2 diabetes + HIIT (T2D + Ex). T2D was induced by a high-fat diet plus a single dose of streptozotocin (STZ). Rats in Ex and T2D + Ex groups performed 8 weeks of HIIT (running at 8-95% of V_max, 4-10 intervals). Insulin and adiponectin levels in serum and hippocampus were measured along with hippocampal expression of insulin and adiponectin receptors, phosphorylated AMPK, dephosphorylated GSK3β, and phosphorylated tau. Homeostasis model assessment for insulin resistance (HOMA-IR), homeostasis model assessment for insulin resistance beta (HOMA-β), and quantitative insulin sensitivity check index (QUICKI) were calculated to assess insulin resistance and sensitivity. T2D decreased insulin and adiponectin levels in serum and hippocampus, as well as the hippocampal levels of insulin and adiponectin receptors and AMPK, but increased GSK3β and tau in the hippocampus. HIIT reversed diabetes-induced impairments and consequently decreased tau accumulation in the hippocampus of diabetic rats. HOMA-IR, HOMA-β, and QUICKI were improved in Ex and T2D + Ex groups. Overall, our results confirmed that T2D has undesirable effects on the levels of some Alzheimer's-related factors in the hippocampus, and HIIT could ameliorate these impairments in the hippocampus.

Canagliflozin alleviates valproic acid-induced autism in rat pups: Role of PTEN/PDK/PPAR-γ signaling pathways

Autism is complex and multifactorial, and is one of the fastest growing neurodevelopmental disorders. Canagliflozin (Cana) is an antidiabetic drug that exhibits neuroprotective properties in various neurodegenerative syndromes. This study investigated the possible protective effect of Cana against the valproic acid (VPA)-induced model of autism. VPA was injected subcutaneously (SC) into rat pups at a dose of 300 mg/kg, twice daily on postnatal day-2 (PD-2) and PD-3, and once on PD-4 to induce an autism-like syndrome. Graded doses of Cana were administered (5 mg/kg, 7.5 mg/kg, and 10 mg/kg, P.O.) starting from the first day of VPA injections and continued for 21 days. At the end of the experiment, behavioral tests and histopathological alterations were assessed. In addition, the gene expression of peroxisome proliferator-activated receptor γ (PPAR γ), lactate dehydrogenase A (LDHA), pyruvate dehydrogenase kinase (PDK), cellular myeloctomatosis (c-Myc) with protein expression of glucose transporter-1 (GLUT-1), phosphatase and tensin homolog (PTEN), and level of acetylcholine (ACh) were determined. Treatment with Cana significantly counteracted histopathological changes in the cerebellum tissues of the brain induced by VPA. Cana (5 mg/kg, 7.5 mg/kg, and 10 mg/kg) improved sociability and social preference, enhanced stereotypic behaviors, and decreased hyperlocomotion activity, in addition to its significant effect on the canonical Wnt/β-catenin pathway via the downregulation of gene expression of LDHA (22%, 64%, and 73% in cerebellum tissues with 51%, 60%, and 75% in cerebrum tissues), PDK (27%, 50%, and 67% in cerebellum tissues with 34%, 66%, and 77% in cerebrum tissues), c-Myc (35%, 44%, and 72% in cerebellum tissues with 19%, 58%, and 79% in cerebrum tissues), protein expression of GLUT-1 (32%, 48%, and 49% in cerebellum tissues with 30%, 50%, and 54% in cerebrum tissues), and elevating gene expression of PPAR-γ (2, 3, and 4 folds in cerebellum tissues with 1.5, 3, and 9 folds in cerebrum tissues), protein expression of PTEN (2, 5, and 6 folds in cerebellum tissues with 6, 6, and 10 folds in cerebrum tissues), and increasing the ACh levels (4, 5, and 7 folds) in brain tissues. The current study confirmed the ameliorating effect of Cana against neurochemical and behavioral alterations in the VPA-induced model of autism in rats.

Histamine H3 receptor antagonist, ciproxifan, alleviates cognition and synaptic plasticity alterations in a valproic acid-induced animal model of autism

RATIONALE

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by deficits in social communication and cognitive behaviors. Histamine H3 receptor (H3R) antagonists are considered as therapeutic factors for treating cognitive impairments.

OBJECTIVES

The aim of the present study was to evaluate the effects of the H3R antagonist, ciproxifan (CPX), on cognition impairment especially, spatial learning memory, and synaptic plasticity in the CA1 region of the hippocampus in autistic rats.

METHODS

Pregnant rats were injected with either valproic acid (VPA) (600 mg/kg, i.p.) or saline on an embryonic day 12.5 (E12.5). The effects of the H3R antagonist, ciproxifan (CPX) (1, 3 mg/kg, i.p.), were investigated on learning and memory in VPA-exposed rat pups and saline-exposed rat pups using Morris water maze (MWM) and social interaction tasks. The H2R antagonist, famotidine (FAM) (10, 20, 40 mg/kg, i.p.), was used to determine whether brain histaminergic neurotransmission exerted its procognitive effects through the H2R. In addition, synaptic reinforcement was evaluated by in vivo field potential recording.

RESULTS

The results showed that VPA-exposed rat pups had significantly lower sociability and social memory performance compared to the saline rats. VPA-exposed rat pups exhibited learning and memory impairments in the MWM task. In addition, VPA caused suppression of long-term potentiation (LTP) in the CA1 area of the hippocampus. Our results demonstrated that CPX 3 mg/kg improved VPA-induced cognitive impairments and FAM 20 mg/kg attenuated cognitive behaviors as well as electrophysiological properties.

CONCLUSIONS

CPX 3 mg/kg improved VPA-induced impairments of LTP as well as learning and memory deficits through H2R.

Trehalose Attenuates Learning and Memory Impairments in Aged Rats via Overexpression of miR-181c

MicroRNAs have been recognized as important regulators of the aging process. Trehalose, a natural disaccharide, displays protective effects against neuronal impairment through several mechanisms. However, little is known about the interactive effects of aging and trehalose on behavioral function and underlying miRNA expression patterns in the hippocampus of young and old rats. Male Wistar rats were divided into four groups. Two groups of aged (24 months) and young (4 months) rats were administered 2% trehalose solution for 30 days. Two other groups of aged and young rats received regular tap water. At the end of treatment, rats were assessed for cognitive behavior using the Morris water maze test. The expression level of miR-181c and mir-34c was also measured by qRT-PCR. We found that trehalose treatment reduced learning and memory impairment in old rats compared to control old animals (p < 0.05). In contrast, cognitive performance was not significantly improved in trehalose-treated young rats in comparison with young controls (p > 0.05). We also showed that the expression level of miR-181c was significantly increased in trehalose-treated rats (p < 0.01). However, analysis of miR-34c expression level indicated no significant difference between trehalose-treated old rats and non-treated old animals (p > 0.05). Our results indicated that trehalose treatment improved learning and memory function in aged rats by targeting miR-181c. Therefore, trehalose administration may provide a therapeutic strategy to ameliorate age-associated cognitive impairment.

Sex difference in cognitive behavioral alterations and barrel cortex neuronal responses in rats exposed prenatally to valproic acid under continuous environmental enrichment

Autism spectrum disorder is a developmental disorder that can affect social interactions and sensory-motor behaviors. The present study investigates the effect of environmental enrichment (EE) on behavioral alterations and neuron responses associated with the barrel cortex of young adult female and male rats exposed prenatally to valproic acid (VPA). Pregnant female rats were pretreated with either saline or VPA (500 mg/kg, IP) on day 12.5 of gestation. Male and female pups were exposed to either EE or standard-setting (non-enrichment) conditions for 1 month (between postnatal day [PND] 30 and 63-65) and were divided into non-EE (control), EE, VPA, and VPA + EE groups. Three-chamber sociability and social novelty, acoustic startle reflex, and texture discrimination tests were conducted on PND 62. Responses of barrel cortex neurons of male pups were evaluated using the extracellular single-unit recording technique on PND 63-65. Results showed that the performance of rats of both sexes in social interactions, texture discrimination tasks, and acoustic startle reflex significantly decreased in the VPA groups compared with the control rats (P < 0.05). In this regard, EE attenuated the altered deficit performance observed in the VPA animals compared with the VPA-EE animals (P < 0.05). The performance of females was better than males in the discrimination tasks and acoustic startle reflex. In contrast, males were better than females in the three-chamber social interaction test. Additionally, the excitatory receptive field response magnitude of the barrel cortex neurons in the VPA + EE group increased compared with the VPA group (P < 0.05). The results suggest that continuous EE can attenuate cognitive function disturbances in autistic-like rats and, at least at the behavioral level, the effects depend on sex.