Lavandula angustifolia and combination of Lavandula angustifolia and Zataria multiflora administration attenuates prenatal lead-exposed induced learning and memory impairments in male rats

Aggravation of cognitive impairments in the valproic acid-induced animal model of autism in BALB/c mice infected with Toxoplasma gondii

PURPOSE

Toxoplasmosis is a disease caused by infection with a type of coccidial protozoan parasite called Toxoplasma gondii. The relationship between toxoplasmosis and cognitive disorders in neurodegenerative diseases has been proven. There is also evidence that children born to Toxoplasma-infected mothers are more likely to develop autism.

METHODS

In the present study, Toxoplasma-infected pregnant BALB/c mice were given valproic acid to induce autism in their male offspring, and their social behaviors, learning, and memory were examined. Chronic toxoplasmosis was established in BALB/c mice by intraperitoneal injection of cyst form of T. gondii. To induce autism, 600 mg/kg of valproic acid was injected intraperitoneally into mice on the 12.5th day of pregnancy. The behavioral experiments, such as social interaction, novel object recognition, and passive avoidance tasks, were performed on male offspring at 50 days.

RESULTS

Toxoplasma and valproic acid during the embryonic period caused social communication deficits and disrupted recognition memory and avoidance memory in offspring. Our findings showed that administering valproic acid to Toxoplasma-infected mothers exacerbates cognitive disorders in their offspring.

Transmission of behavioral and cognitive impairments across generations in rats subjected to prenatal valproic acid exposure

BACKGROUND

Autism spectrum disorder (ASD) represents an inheritable neurodevelopmental condition characterized by social communication deficits and repetitive behaviors. Numerous studies have underscored the significant roles played by genetic and environmental factors in the etiology of ASD, and these factors are known to perpetuate behavioral impairments across generations.

OBJECTIVES

The primary objective of this study was to assess the behavioral and cognitive attributes in the second filial (F2) generation of male and female rats, with a particular focus on those whose parents had been exposed to valproic acid (VPA) during embryonic development.

METHODS

In this study, a cohort of 32 male and 32 female rats from the second filial (F2) generation, referred to as Mother.ASD, Father.ASD, or Both.ASD, was examined. These designations indicate whether the mother, father, or both parents had experienced embryonic exposure to valproic acid (600 mg/kg, i.p.). During adolescence, the F2 pups underwent behavioral and cognitive assessments, including open field testing, marble burying, social interaction evaluations, and Morris water maze tasks.

RESULTS

Our data revealed that while both the Mother.ASD and Father.ASD groups, regardless of sex, exhibited elevated anxiety-like behavior in the open field test. Only the Mother.ASD group displayed repetitive behaviors and deficits in social memory. Additionally, spatial memory impairments were observed in both sexes. These findings highlight the transmission of autistic-like behaviors in the offspring of Mother.ASD rats from both sexes. Nevertheless, future research endeavors should be more targeted in identifying the specific genes responsible for this transmission.

CONCLUSION

In summary, our findings underscore the transmission of autistic-like behaviors, including anxiety-like behavior, repetitive actions, impairments in social interactions, and deficits in memory, to the offspring of the Mother.ASD group, irrespective of their sex.

Amelioration of cognition impairments in the valproic acid-induced animal model of autism by ciproxifan, a histamine H3-receptor antagonist

Autism spectrum disorder is a neurodevelopmental disorder characterized by deficits in social communication and repetitive behavior. Many studies show that the number of cognitive impairmentscan be reduced by antagonists of the histamine H3 receptor (H3R). In this study, the effects of ciproxifan (CPX) (1 and 3 mg/kg, intraperitoneally) on cognitive impairments in rat pups exposed to valproic acid (VPA) (600 mg/kg, intraperitoneally) wereexamined on postnatal day 48-50 (PND 48-50) using marble-burying task (MBT), open field, novel object recognition (NOR), and Passive avoidance tasks. Famotidine (FAM) (10, 20, and 40 mg/kg, intraperitoneally) was also used to determine whether histaminergic neurotransmission exerts its procognitive effects via H2 receptors (H2Rs). Furthermore, a histological investigation was conducted to assess the degree of degeneration of hippocampal neurons. The results revealed that repetitive behaviors increased in VPA-exposed rat offspring in the MBT. In addition, VPA-exposed rat offspring exhibited more anxiety-like behaviors in the open field than saline-treated rats. It was found that VPA-exposed rat offspring showed memory deficits in NOR and Passive avoidance tasks. Our results indicated that 3 mg/kg CPX improved cognitive impairments induced by VPA, while 20 mg/kg FAM attenuated them. We concluded that 3 mg/kg CPX improved VPA-induced cognitive impairments through H3Rs. The histological assessment showed that the number of CA1 neurons decreased in the VPA-exposed rat offspring compared to the saline-exposed rat offspring, but this decrease was not significant. The histological assessment also revealed no significant differences in CA1 neurons in VPA-exposed rat offspring compared to saline-exposed rat offspring. However, CPX3 increased the number of CA1 neurons in the VPA + CPX3 group compared to the VPA + Saline group, but this increase was not significant. This study showed that rats prenatally exposed to VPA exhibit cognitive impairments in the MBT, open field, NOR, and Passive avoidance tests, which are ameliorated by CPX treatment on PND 48-50. In addition, morphological investigations showed that VPA treatment did not lead to neuronal degeneration in the CA1 subfield of the hippocampus in rat pups.

Music alleviates cognitive impairments in an animal model of autism

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by core symptoms including impairment in social communication and restrictive and repetitive behaviors and interests. Music has emerged in the past decade as an intervention therapy for children with ASD. The aim of the present study was to evaluate the effects of music on cognition impairments in the valproic acid (VPA) rat model of autism. The VPA was administered for animal modeling of autism on embryonic day 12.5 (E12.5) (600 mg/kg). Male and female pups were sub divided into four main groups (Saline.Non-music, VPA.Non-music, Saline.Music, and VPA.Music). The rats in the music groups were exposed to Mozart's piano sonata K.448 for 30 days (4 h/day), from postnatal day (PND) 21 to 50. Autistic-like behaviors were tested using a social interaction, the Morris water maze (MWM), and a passive avoidance tasks at the end of the PND 50. Our results demonstrated that VPA-exposed rat pups had significantly lower sociability and social memory performance compared with the saline-exposed rats in both sexes. VPA-exposed rat pups exhibited learning and memory impairments in the MWM and passive avoidance tasks. Our results demonstrated that music improved sociability in VPA-exposed rats, especially in males. Furthermore, our findings revealed that music improved learning impairments in VPA-exposed male rats in MWM task. In addition, music improved spatial memory impairments in VPA-exposed rats of both sexes. We also found that music improved passive avoidance memory impairments in VPA-exposed rats of both sexes, especially in females. More investigation in future studies are needed.

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.

Effects of short environmental enrichment on early-life adversity induced cognitive alternations in adolescent rats

Early-life experiences, including parental care, affect cognitive performance later in life. Being exposed to early-life maternal separation (MS) increases susceptibility to stress-related psychopathology. Previous studies suggest that MS could induce learning and memory impairments. Since enriched environment (EE) provides more opportunities for exploration and social interaction, in the present study we evaluated the effects of a short EE paradigm with a duration of 13 days on cognitive abilities of maternally separated rats (MS; 180 min/day, postnatal day (PND) 1-21) during adolescence in four experimental groups: Control, Control+EE, MS, and MS+EE. Plasma corticosterone (CORT) and brain-derived neurotrophic factor (BDNF) levels were also measured in experimental animals. We also studied the induction of long-term potentiation (LTP) in the slices of hippocampal CA1 area. The behavioral and electrophysiological assessments were started at PND 35. MS caused higher basal CORT levels in plasma and impaired spatial learning, memory, and social interaction. LTP induction was also impaired in MS rats and plasma BDNF levels were reduced in these animals. MS also induced more anxiety-like behavior. Short EE reduced plasma CORT levels had the potential to improve locomotor activity and anxiety-like behavior in MS+EE rats and reversed MS-induced impairments of spatial learning, memory, and social behavior. LTP induction and plasma BDNF levels were also enhanced in MS+EE rats. We concluded that short EE might be considered as a therapeutic strategy for promoting cognition.

Maternal separation impairs mother's cognition 1 month beyond the separation

OBJECTIVE

Separation of pups from their dam during the infancy not only has detrimental effects on the pups' brain but also affects dams' behavior. Postpartum stress may affect mothers' cognitive functions. In the present study, by using a 180-min day-1 maternal separation (MS) paradigm, we assessed anxiety-like behavior and locomotor activity of rat dams which experienced separation from postnatal day (PND) 1 until weaning. We tried for the first time to clarify whether such separation impairs dam's performance in the Morris water maze.

METHOD

We assessed dams' behavior at three time points: 24 h, 1 week, and 1 month after weaning. Therefore, the six groups consisted of control (CTRL) 24 h, 1 week, and 1 month and MS 24 h, 1 week, and 1 month, which was allocated in this study.

RESULTS

Our results revealed that although MS-24 h and MS-1 week groups had intact locomotor activity, MS-1 month group showed less locomotor activity in the open field. Moreover, MS-induced anxiety-like behavior was more pronounced in MS-1 week and MS-1 month dams. Spatial learning and memory was also impaired only in MS-1 month dams.

CONCLUSION

We can conclude that MS induces cognitive impairments in dam that may appear not immediately after the separation but a few weeks after such stressful event.