Bate palmas mutant mice as a model of Kabuki syndrome: Higher susceptibility to infections and vocalization impairments?

The recessive mutant mouse bate palmas (bapa) arose from N-ethyl-N-nitrosourea mutagenesis. Previous studies of our group revealed some behavioral impairments and a mutation in the lysine (K)-specific methyltransferase 2D (Kmt2d) gene. Because mutations in the KMT2D gene in humans are mainly responsible for Kabuki syndrome, this study was proposed to validate bapa mice as a model of Kabuki syndrome. Besides other symptoms, Kabuki syndrome is characterized by increased susceptibility to infections and speech impairments, usually diagnosed in the early childhood. Thus, juvenile male and female bapa mice were studied in different developmental stages (prepubertal period and puberty). To induce sickness behavior and to study infection susceptibility responses, lipopolysaccharide (LPS) was used. To study oral communication, ultrasonic vocalizations were evaluated. Behavioral (open-field test) and central (astrocytic glial fibrillary acidic protein [GFAP] and tyrosine hydroxylase [TH]) evaluations were also performed. Control and bapa female mice emitted 31-kHz ultrasounds on prepubertal period when exploring a novel environment, a frequency not yet described for mice, being defined as 31-kHz exploratory vocalizations. Males, LPS, and puberty inhibited these vocalizations. Bapa mice presented increased motor/exploratory behaviors on prepubertal period due to increased striatal TH expression, revealing striatal dopaminergic system hyperactivity. Combining open-field behavior and GFAP expression, bapa mice did not develop LPS tolerance, that is, they remained expressing signs of sickness behavior after LPS challenge, being more susceptible to infectious/inflammatory processes. It was concluded that bapa mice is a robust experimental model of Kabuki syndrome.

Zinc, but not paracetamol, prevents depressive-like behavior and sickness behavior, and inhibits interferon-gamma and astrogliosis in rats.

Considering all mental and addictive disorders, depression is the most responsible for years of life lost due to premature mortality and disability. Antidepressant drugs have limited effectiveness. Depression can be triggered by immune/inflammatory factors. Zinc and paracetamol interfere with immune system and have demonstrated beneficial effects on depression treatment when administered concomitant with antidepressant drugs. The objective of this study was to test zinc and/or paracetamol as treatments of depressive-like behavior, sickness behavior, and anxiety in rats, as well as to understand the central and peripheral mechanisms involved. Sickness behavior and depressive-like behavior were induced in rats with repetitive lipopolysaccharide (LPS, 1 mg/kg for two consecutive days) administrations. Rats received zinc and/or paracetamol for three consecutive days. Sickness behavior (daily body weight and open field general activity); anxiety (light-dark test); depressive-like/antidepressant behavior (forced swim test); plasma corticosterone and interferon (IFN)-gamma levels; and glial fibrillary acidic protein (GFAP) and tyrosine hydroxylase (TH) brain expression were evaluated. LPS induced sickness behavior and depressive-like behavior, as well as elevated IFN-gamma levels and increased GFAP expression. Zinc prevented both behavioral and biochemical impairments. Paracetamol and zinc + paracetamol association induced only slight beneficial effects. Anxiety, corticosterone, and TH do not seem be related with depression and the other behavioral and neuroimmune changes. In conclusion, zinc treatment was beneficial for sickness behavior and depressive-like behavior without concomitant administration of antidepressants. IFN-gamma and GFAP were linked with the expression of sickness behavior and depressive-like behavior and were also involved with the antidepressant effects. Therefore, zinc, IFN-gamma, and GFAP pathways should be considered for depression treatment.

Billings reservoir water used for human consumption presents microbiological contaminants and induces both behavior impairments and astrogliosis in zebrafish.

The Billings reservoir is the largest water-storage facility in the São Paulo Metropolitan Region, with only a small part of the reservoir used for water supply. Recently, the São Paulo Metropolitan Region has experienced the greatest water collapse ever recorded. Thus, the intensification of use of the Billings reservoir should be considered. The objective of this study was to evaluate the quality of the water from different areas of the Billings reservoir related to human consumption (water supply and fishing): Rio Pequeno, Rio Grande, and Bororé rivers. We performed microbiological and physical studies on one water sample collected at each of these sites. Adult zebrafish were exposed to such water samples and their behaviors were evaluated. Finally, we studied central glial fibrillary acidic protein (GFAP) expression, which is related to neuroinflammatory processes. Water samples from Rio Pequeno, Rio Grande, and Bororé presented microbiological contamination for Escherichia coli and heterotrophic bacteria. Water from the Rio Pequeno river induced both motor/exploratory impairments and anxiogenic-like behavior in zebrafish. Water from the Bororé river induced behaviors in zebrafish related to respiratory impairments (hypoxia) as well as higher alarm reaction. Zebrafish exposed to water from the Bororé also presented astrogliosis, which seems to have happened in detrimental of the high heterotrophic bacterial contamination. Rio Grande and Bororé water increased the lethality rates. Considering the present results of microbiological contaminants and behavior impairments, lethality, as well as astrogliosis in zebrafish, the water from Rio Pequeno, Rio Grande, and Bororé rivers should be considered unacceptable for human use in their untreated state. The Basic Sanitation Company of the State of Sao Paulo should consider adopting rigorous processes of microbiological water treatment. Authorization for fishing at Bororé river should be reconsidered.

Ivermectin prevents stress-induced testicular damage in juvenile rats.

Ivermectin is a popular antiparasitic drug used in veterinary and human medicine. Studies by our group have shown that therapeutic doses of ivermectin induce some brain and behavioral impairments, especially in the reproductive sphere. So far, the studies were focused in adulthood. Considering that juveniles are more susceptible to drugs during developmental stages and both farm/domestic animals and humans have been medicated with ivermectin in youth, it is necessary to evaluate the possible harm effects in youth. The stress variable is also important, as it potentially influences the effects produced by ivermectin. Therefore, the objective of this study was to evaluate morphofunctional and hormonal reproductive aspects of juvenile rats exposed to ivermectin and/or stressed. Prepubertal male rats were treated with 0.2 or 1.0 mg/kg of ivermectin (a therapeutic dose and a higher dose, respectively). Rats were also submitted to a restraint stress session. The testis morphology and histology were analyzed and plasma testosterone levels were measured. The two doses of ivermectin did not induce a biologically relevant effect on testis and testosterone levels of rats. However, restraint stress impaired macroscopic and microscopic morphometric and stereological parameters, as well as the histology of the testis: it increased the relative testis weight, the tubular diameter, the tubular luminal diameter, and the tubular cellular index, and injured the interstitial area. Previous treatment of juvenile rats with ivermectin prevented most of the stress-induced testes injuries. In conclusion, in addition to be a remarkable antiparasitic agent, ivermectin prevented stress-induced testes injuries in juvenile rats.

Progressive tremor and motor impairment in seizure-prone mutant tremor mice are associated with neurotransmitter dysfunction.

BACKGROUND: The tremor mutant mice present motor impairments comprised of whole-body tremors, ataxia, decreased exploratory behavior, and audiogenic seizures. OBJECTIVES: This study aims to investigate the development of motor dysfunction in this mutant mouse and the relationships with cortical, striatal, and cerebellar levels of GABA, glutamate, glycine, dopamine (DA), serotonin (5-HT), noradrenaline (NOR), and its metabolites. The serum cytokines levels, myelin content, and the astrocytic expression of the glial fibrillary acidic protein (GFAP) investigated the possible influence of inflammation in motor dysfunction. RESULTS: Relative to wild-type (WT) mice, the tremor mice presented: increased tremors and bradykinesia associated with postural instability, decreased range of motion, and difficulty in initiating voluntary movements directly proportional to age; reduced step length for right and left hindlimbs; reduced cortical GABA, glutamate and, aspartate levels, the DOPAC/DA and ratio and increased the NOR levels; in the striatum, the levels of glycine and aspartate were reduced while the HVA levels, the HVA/DA and 5HIAA/5-HT ratios increased; in the cerebellum the glycine, NOR and 5-HIAA levels increased. CONCLUSIONS: We suggest that the motor disturbances resulted mainly from the activation of the indirect striatal inhibitory pathway to the frontal cortex mediated by GABA, glutamate, and aspartate, reducing the dopaminergic activity at the prefrontal cortex, which was associated with the progressive tremor. The reduced striatal and increased cerebellar glycine levels could be partially responsible for the mutant tremor motor disturbances.

Hypoactivity of the central dopaminergic system and autistic-like behavior induced by a single early prenatal exposure to lipopolysaccharide.

The aim of the present study was to evaluate the behavioral patterns associated with autism and the prevalence of these behaviors in males and females, to verify whether our model of lipopolysaccharide (LPS) administration represents an experimental model of autism. For this, we prenatally exposed Wistar rats to LPS (100 µg/kg, intraperitoneally, on gestational day 9.5), which mimics infection by gram-negative bacteria. Furthermore, because the exact mechanisms by which autism develops are still unknown, we investigated the neurological mechanisms that might underlie the behavioral alterations that were observed. Because we previously had demonstrated that prenatal LPS decreases striatal dopamine (DA) and metabolite levels, the striatal dopaminergic system (tyrosine hydroxylase [TH] and DA receptors D1a and D2) and glial cells (astrocytes and microglia) were analyzed by using immunohistochemistry, immunoblotting, and real-time PCR. Our results show that prenatal LPS exposure impaired communication (ultrasonic vocalizations) in male pups and learning and memory (T-maze spontaneous alternation) in male adults, as well as inducing repetitive/restricted behavior, but did not change social interactions in either infancy (play behavior) or adulthood in females. Moreover, although the expression of DA receptors was unchanged, the experimental animals exhibited reduced striatal TH levels, indicating that reduced DA synthesis impaired the striatal dopaminergic system. The expression of glial cell markers was not increased, which suggests that prenatal LPS did not induce permanent neuroinflammation in the striatum. Together with our previous finding of social impairments in males, the present findings demonstrate that prenatal LPS induced autism-like effects and also a hypoactivation of the dopaminergic system.

Maternal exposure to picrotoxin modifies the response of the GABAA receptor during sexual behavior of adult male rat offspring.

This study investigated whether perinatal exposure to picrotoxin, a GABAA antagonist, modifies the effect of muscimol, a GABAA agonist, on the sexual behavior of adult male rats. Two hours after birth and then once daily during the next 9 days of lactation, dams received picrotoxin (0.75 mg/kg subcutaneously) or saline (1 ml/kg subcutaneously). The adult male offspring from the picrotoxin and saline groups received saline (1 ml/kg intraperitoneally) or muscimol (1 mg/kg intraperitoneally), and 15 min later, their sexual behavior was assessed. Muscimol treatment in the saline-exposed group increased the mount and intromission latencies. However, these effects were absent in the picrotoxin-exposed groups. The latencies to first ejaculation, postejaculatory mount, and intromission were decreased in both picrotoxin-exposed groups relative to the saline-exposed groups. The picrotoxin+muscimol-treated rats required more intromissions to ejaculate and the picrotoxin-exposed groups made more ejaculations than the saline-exposed groups. Thus, muscimol treatment did not increase the mount and intromission latencies following picrotoxin exposure, but increased the ejaculation frequency, which did not differ between the picrotoxin+muscimol and the picrotoxin+saline groups. These data indicate that perinatal picrotoxin treatment interfered with GABAA receptor development.

Perinatal exposure to glyphosate-based herbicides induced neurodevelopmental behaviors impairments and increased oxidative stress in the prefrontal cortex and hippocampus in offspring.

Glyphosate is the organophosphate pesticide most widely used in the world. Recent studies correlate exposure to glyphosate and the emergence of neurodevelopmental disorders. Therefore, it was objective to propose a rat model of perinatal exposure to glyphosate-based herbicides (GBH) to study associated neurodevelopmental disorders. Behavioral aspects and brain pathways were assessed in the prepubertal phase. For this, maternal treatment occurred throughout the entire gestation period (from GD0) until weaning on postnatal day 22 (PND 22). Control group received oral gavage with 5 mL/kg of saline per day and GBH group received oral gavage with 50 mg/kg of GBH per day (n = 10 per group). Maternal behavior was evaluated in PND 2-6. Offspring were evaluated for quantification of ultrasonic vocalizations (PND 5); homing behavior test (PND 13); and hole board, social play behavior, open field, and object recognition tests (PND 28-32). Prefrontal cortex and hippocampus of the offspring were processed to evaluate oxidative stress. Maternal exposure to GBH impaired early social communication, olfactory discrimination, social play behavior, and the exploration of objects, in addition to increasing repetitive and stereotyped movements. GBH also increased oxidative stress. Therefore, perinatal GBH exposure induced behavioral and oxidative stress impairments in rats associated with neurodevelopmental disorders. The manifestations found in the offspring are in accordance with symptoms of autism spectrum disorder.

Prenatal lipopolysaccharide reduces social behavior in male offspring.

OBJECTIVE: This study investigated the relationship between maternal sickness behavior during pregnancy and offspring development and behavior. METHODS: Pregnant Wistar rats were administered with lipopolysaccharide (LPS, 100 microg/kg, i.p.) on gestation day (GD) 9.5. Dams' sickness behavior was analyzed, and at birth, offspring number and weight were evaluated. Male offspring was evaluated through physical development, play behavior, adult social interaction, plus maze studies and morphological analysis of the brain. RESULTS: Results, with respect to the control group, showed that: (1) LPS decreased general activity, food intake, and weight gain in dams, but no pyrexia was observed following treatment; (2) LPS reduced litter size, but no alterations in physical development were observed; (3) LPS reduced play behavior parameters in baby rats; (4) LPS decreased adult social interaction; (5) no alterations were observed between groups on plus maze studies; (6) no differences were observed between groups on morphological analyses of the brain. CONCLUSION: These data reveal that LPS administered on GD 9.5 impaired male offspring's social behavior in infancy and adulthood. These results may be related to an alteration in motivational states or/and increased anxiety.

Prenatal lipopolysaccharide exposure affects maternal behavior and male offspring sexual behavior in adulthood.

OBJECTIVE: This study investigates the effects of prenatal lipopolysaccharide (LPS) exposure on the maternal behavior of pregnant rats and the physical development and sexual behavior of their male offspring in adulthood. METHODS: For two experiments, pregnant rats were injected with LPS (250 microg/kg, i.p.) on gestation day (GD) 21. In the first experiment, the maternal behavior (postnatal day, PND, 6) and the dam's open-field general activity (PND7) were evaluated. In the second experiment, the maternal pre- and postnatal parameters, the pup's development, the offspring's sexual behavior in adulthood, and the pup's organ weights were assessed. RESULTS: Compared to the control group, the LPS-treated dams presented reduced maternal behavior, decreased general activity, a smaller body weight difference between GD21 and PND1, a greater number of perinatal deaths, and smaller litters. For the male pups, LPS treatment resulted in a decreased body weight on PND2, whereas the anogenital distance and the day of testis descent were not modified. The male sexual behavior was impaired by prenatal LPS. Particularly the number of ejaculating animals was reduced. The testis weight was also lower in the prenatally LPS-treated rats than in the control rats. CONCLUSION: We propose that prenatal LPS exposure on GD21 acts as an imprinting factor that interferes with the programming of brain sexual determination in offspring.

Pioglitazone abolishes cognition impairments as well as BDNF and neurotensin disturbances in a rat model of autism.

We have shown that exposure of rats to lipopolysaccharide (LPS) during gestation induces autistic-like behaviors in juvenile offspring and pioglitazone post treatment corrects social and communication deficits. The first objective of the present study was to evaluate the cognition of the rats, because this is also a behavioral sphere committed in autism. Second, biomarkers related to pioglitazone pathways and autism were studied to try to understand their mechanisms. We used our rat model of autism and pioglitazone was administered daily to these young offspring. T-maze spontaneous alternations tests, plasma levels of brain-derived neurotrophic factor (BDNF), beta-endorphin, neurotensin, oxytocin, and substance P were all studied. Exposure of rats to LPS during gestation induced cognitive deficits in the young offspring, elevated BDNF levels and decreased neurotensin levels. Daily postnatal pioglitazone treatment abolished cognition impairments as well as BDNF and neurotensin disturbances. Together with our previous studies, we suggest pioglitazone as a candidate for the treatment of autism, because it improved the responses of the three most typical autistic-like behaviors. BDNF and neurotensin also appeared to be related to the autistic-like behaviors and should be considered for therapeutic purposes.

Therapeutical doses of ivermectin and its association with stress disrupt motor and social behaviors of juvenile rats and serotonergic and dopaminergic systems.

Ivermectin is a human and veterinary antiparasitic drug which is one of the most widely used in the world. Studies from our group have revealed several behavioral and neurochemical impairments induced by therapeutic doses of ivermectin in adult rats. However, the effects on juveniles remain unknown. Ivermectin has been prescribed for juvenile humans, pets and farm animals, which still show remarkable development and postnatal maturation and may be more susceptible to drug interventions. Hence, we studied the behavioral and neurochemical effects of two therapeutical doses (0.2 and 1.0 mg/kg) of ivermectin in juvenile rats. As it is underestimated in prescriptions, the stress factor was also studied. Ivermectin 1.0 mg/kg induced hyperlocomotion in juvenile rats. Association of 1.0 mg/kg ivermectin with stress induced hypolocomotion in rats. Ivermectin 1.0 mg/kg whether or not associated with stress exacerbated socialization of rats. Ivermectin did not induce anxiety-like behavior neither affected corticosterone levels of juvenile rats. The motor/exploratory behavioral findings induced by association of ivermectin and stress seem to be triggered after the increase in the striatal serotonergic system activity. Association of ivermectin with stress increased striatal dopamine levels, which increased (excessive) social play behavior. Our results suggest a review of the prescribed dose of ivermectin for juvenile humans and pets. Moreover, the stress factor should be considered for ivermectin medical prescriptions, since it may exacerbate behavioral and neurochemical disturbances.

Luffa operculata fruit aqueous extract induces motor impairments, anxiety-like behavior, and testis damage in rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Luffa operculata (L.) Cogn., Cucurbitaceae (buchinha-do-norte), aqueous extract (EBN) is popularly used to relieve symptoms of sinusitis and as abortive. AIM OF THE STUDY: As neurotoxicity and toxicity studies on the male reproductive system are scarce, the present study aimed at quantitatively addressing the question. MATERIALS AND METHODS: Male adult rats were observed in the open field (OF) and in the light-dark box test (LDB) to evaluate locomotion and anxiety. Macroscopical and microscopical alterations on the rats' testes were also studied. The rats were divided into two groups, control (GC) and experimental (GE). GE received 1.0 mg/kg per day of EBN, orally, for five consecutive days, whereas GC received water. On the 6th day, each animal was evaluated in OF and in LDB for 3 min in each apparatus. After that, the left testicles were studied. RESULTS: In the OF, GE showed decreased locomotion, increased immobility time and decreased grooming and remained for less time in the center of the apparatus. In LDB, GE showed significant difficulty in moving into the light side of the device and remained longer in the dark side, exhibiting less displacement on both sides and less transitions between sides. Testicle weights, relative weights, testicular volume, cranial-caudal and lateral-lateral axes presented an increase in relation to the GC. Microscopic changes were observed in parenchyma, lumen and diameter of seminiferous tubules. Leydig cell numbers were decreased in GE. CONCLUSIONS: The administration of EBN induced anxiety-like behavior, impaired locomotion and altered the testes morphology of rats.

Prenatal lipopolysaccharide induces hypothalamic dopaminergic hypoactivity and autistic-like behaviors: Repetitive self-grooming and stereotypies.

Previous investigations by our group have shown that prenatal exposure to lipopolysaccharide (LPS), which mimics infection by gram-negative bacteria, induces social, cognitive, and communication deficits. For a complete screening of autistic-like behaviors, the objective of this study was to evaluate if our rat model also induces restricted and repetitive stereotyped behaviors. Thus, we studied the self-grooming microstructure. We also studied the neurochemistry of hypothalamus and frontal cortex, which are brain areas related to autism to better understand central mechanisms involved in our model. Prenatal LPS exposure on gestational day 9.5 increased the head washing episodes (frequency and time), as well as the total self-grooming. However, body grooming, paw/leg licking, tail/genital grooming, and circling behavior/tail chasing did not vary significantly among the groups. Moreover, prenatal LPS induced dopaminergic hypoactivity (HVA metabolite and turnover) in the hypothalamus. Therefore, our rat model induced restricted and repetitive stereotyped behaviors and the other main symptoms of autism experimentally studied in rodent models and also found in patients. The hypothalamic dopaminergic impairments seem to be associated with the autistic-like behaviors.

A new exposure model to evaluate smoked illicit drugs in rodents: A study of crack cocaine.

The use of smoked illicit drugs has spread dramatically, but few studies use proper devices to expose animals to inhalational abused drugs despite the availability of numerous smoking devices that mimic tobacco exposure in rodents. Therefore, the present study developed an inexpensive device to easily expose laboratory animals to smoked drugs. We used crack cocaine as the drug of abuse, and the cocaine plasma levels and the behaviors of animals intoxicated with the crack cocaine were evaluated to prove inhaled drug absorption and systemic activity. We developed an acrylic device with two chambers that were interconnected and separated by a hatch. Three doses of crack (100, 250, or 500 mg), which contained 63.7% cocaine, were burned in a pipe, and the rats were exposed to the smoke for 5 or 10 min (n=5/amount/period). Exposure to the 250-mg dose for 10 min achieved cocaine plasma levels that were similar to those of users (170 ng/mL). Behavioral evaluations were also performed to validate the methodology. Rats (n=10/group) for these evaluations were exposed to 250 mg of crack cocaine or air for 10 min, twice daily, for 28 consecutive days. Open-field evaluations were performed at three different periods throughout the experimental design. Exposed animals exhibited transient anorexia, increased motor activity, and shorter stays in central areas of the open field, which suggests reduced anxiety. Therefore, the developed model effectively exposed animals to crack cocaine, and this model may be useful for the investigation of other inhalational abused drugs.

Zinc prevents sickness behavior induced by lipopolysaccharides after a stress challenge in rats.

Sickness behavior is considered part of the specific beneficial adaptive behavioral and neuroimmune changes that occur in individuals in response to infectious/inflammatory processes. However, in dangerous and stressful situations, sickness behavior should be momentarily abrogated to prioritize survival behaviors, such as fight or flight. Taking this assumption into account, we experimentally induced sickness behavior in rats using lipopolysaccharides (LPS), an endotoxin that mimics infection by gram-negative bacteria, and then exposed these rats to a restraint stress challenge. Zinc has been shown to play a regulatory role in the immune and nervous systems. Therefore, the objective of this study was to examine the effects of zinc treatment on the sickness response of stress-challenged rats. We evaluated 22-kHz ultrasonic vocalizations, open-field behavior, tumor necrosis factor α (TNF-α), corticosterone, and brain-derived neurotrophic factor (BDNF) plasma levels. LPS administration induced sickness behavior in rats compared to controls, i.e., decreases in the distance traveled, average velocity, rearing frequency, self-grooming, and number of vocalizations, as well as an increase in the plasma levels of TNF-α, compared with controls after a stressor challenge. LPS also decreased BDNF expression but did not influence anxiety parameters. Zinc treatment was able to prevent sickness behavior in LPS-exposed rats after the stress challenge, restoring exploratory/motor behaviors, communication, and TNF-α levels similar to those of the control group. Thus, zinc treatment appears to be beneficial for sick animals when they are facing risky/stressful situations.

Prenatal zinc prevents communication impairments and BDNF disturbance in a rat model of autism induced by prenatal lipopolysaccharide exposure.

Aims: Previous investigations by our group have shown that prenatal exposure to lipopolysaccharide (LPS),which mimics infections by Gram-negative bacteria, induced autistic-like behavior. No effective treatment yet exists for autism. Therefore, we used our rat model to test a possible treatment for autism.We selected zinc as the prenatal treatment to prevent or ease the impairments induced by LPS because LPS induces hypozincaemia.Materials and methods:We evaluated the effects of LPS and zinc on female reproductive performance. Communication,which is impaired in autism,was tested in pups by ultrasonic vocalizations. Plasma levels of brain-derived neurotrophic factor (BDNF) were determined because it has been considered an autism important biomarker.Key findings: Prenatal LPS exposure reduced offspring number and treatment with zinc prevented this reduction.Moreover, pups that were prenatally exposed to LPS spent longer periods without calling their mothers, and posttreatment with zinc prevented this impairment induced by LPS to the same levels as controls. Prenatal LPS also increased BDNF levels in adult offspring, and posttreatment with zinc reduced the elevation of BDNF to the same levels as controls.Significance: BDNF hyperactivity was also found in several studies of autistic patients. Together with our previous studies, our model of prenatal LPS induced autistic-like behavioral, brain, and immune disturbances. This suggests that it is a valid rat model of autism. Prenatal zinc prevented reproductive, communication, and BDNF impairments.The present study revealed a potential beneficial effect of prenatal zinc administration for the prevention of autism with regard to the BDNF pathway.

Prenatal zinc reduces stress response in adult rat offspring exposed to lipopolysaccharide during gestation.

AIMS: Previous investigations by our group have shown that prenatal treatment with lipopolysaccharide (LPS; 100 µg/kg, intraperitoneally) on gestation day (GD) 9.5 in rats, which mimics infections by Gram-negative bacteria, induces short- and long-term behavioral and neuroimmune changes in the offspring. Because LPS induces hypozincemia, dams were treated with zinc after LPS in an attempt to prevent or ameliorate the impairments induced by prenatal LPS exposure. LPS can also interfere with hypothalamic-pituitary-adrenal (HPA) axis development; thus, behavioral and neuroendocrine parameters linked to HPA axis were evaluated in adult offspring after a restraint stress session. MAIN METHODS: We prenatally exposed Wistar rats to LPS (100 µg/kg, intraperitoneally, on GD 9.5). One hour later they received zinc (ZnSO4, 2 mg/kg, subcutaneously). Adult female offspring that were in metestrus/diestrus were submitted to a 2 h restraint stress session. Immediately after the stressor, 22 kHz ultrasonic vocalizations, open field behavior, serum corticosterone and brain-derived neurotrophic factor (BDNF) levels, and striatal and hypothalamic neurotransmitter and metabolite levels were assessed. KEY FINDINGS: Offspring that received prenatal zinc after LPS presented longer periods in silence, increased locomotion, and reduced serum corticosterone and striatal norepinephrine turnover compared with rats treated with LPS and saline. Prenatal zinc reduced acute restraint stress response in adult rats prenatally exposed to LPS. SIGNIFICANCE: Our findings suggest a potential beneficial effect of prenatal zinc, in which the stress response was reduced in offspring that were stricken with infectious/inflammatory processes during gestation.

Prenatal lipopolysaccharide disrupts maternal behavior, reduces nest odor preference in pups, and induces anxiety: studies of F1 and F2 generations.

The present study analyzed the transgenerational effects of lipopolysaccharide (LPS; 100 µg/kg) administration on gestational day 18 (GD18) of parental generation on maternal-pups interaction of F1 and F2 generations. Also the long term behavioral effects were observed in male of F2 generation. In F1 generation, the reproductive performance, maternal behavior, maternal aggressive behavior, and general activity in the open field in adulthood were analyzed. In F2 generation, body weight at birth and at weaning, nest odor preference, and general activity in the open field and elevated plus maze in adulthood were assessed. Compared to controls, results showed that in the F1 generation, prenatal LPS exposure (1) increased the latency to full maternal behavior, but all of the females grouped the pups and presented full maternal behavior, (2) reduced the total time boxing and fighting, increased the frequency of retrieving the pups, and increased the number of bites, and (3) did not affect reproductive performance or general activity. In F2 generation, compared with controls, the LPS group exhibited (1) a decrease in body weight at weaning, (2) a decrease in nest odor preference, (3) a decrease in the percentage of time spent in the open arms, a decrease in the percentage of time spent in the center, and an increase in the time spent in the closed arms in the elevated plus maze, and (Huang et al.) no affect behavior in the open field. Prenatal LPS exposure improved maternal care in the F1 generation with regard to nursing and pup survival but did not improve the motivational parameters of maternal behavior likely because of a reduction of maternal stimulation by the pups. In the F2 generation, the reduction of nest odor preference in the pups suggests a less maternal recognition. In adulthood, these rats exhibited increased anxiety-like behavior. These data did not result from motor alterations because rats in both the F1 and F2 generations did not show alterations in open field behavior. This transfer of information across generations likely occurred through nongenetic means because the endotoxin was administered at the end of pregnancy. These results may have implications for clinical therapeutics in human disorders and evolution.

LPS exposure increases maternal corticosterone levels, causes placental injury and increases IL-1Β levels in adult rat offspring: relevance to autism.

Maternal immune activation can induce neuropsychiatric disorders, such as autism and schizophrenia. Previous investigations by our group have shown that prenatal treatment of rats on gestation day 9.5 with lipopolysaccharide (LPS; 100 µg/kg, intraperitoneally), which mimics infections by gram-negative bacteria, induced autism-like behavior in male rats, including impaired communication and socialization and induced repetitive/restricted behavior. However, the behavior of female rats was unchanged. Little is known about how LPS-induced changes in the pregnant dam subsequently affect the developing fetus and the fetal immune system. The present study evaluated the hypothalamic-pituitary-adrenal (HPA) axis activity, the placental tissue and the reproductive performance of pregnant Wistar rats exposed to LPS. In the adult offspring, we evaluated the HPA axis and pro-inflammatory cytokine levels with or without a LPS challenge. LPS exposure increased maternal serum corticosterone levels, injured placental tissue and led to higher post-implantation loss, resulting in fewer live fetuses. The HPA axis was not affected in adult offspring. However, prenatal LPS exposure increased IL-1ß serum levels, revealing that prenatal LPS exposure modified the immune response to a LPS challenge in adulthood. Increased IL-1ß levels have been reported in several autistic patients. Together with our previous studies, our model induced autistic-like behavioral and immune disturbances in childhood and adulthood, indicating that it is a robust rat model of autism.