Andreza L. Cipriano

Maternal Deprivation Induces Depressive-like Behaviour and Alters Neurotrophin Levels in the Rat Brain

The present study was aimed to evaluate the behavioral and molecular effects of maternal deprivation in adult rats. To this aim, male rats deprived and non-deprived were assessed in the forced swimming and open-field tests in adult phase. In addition adrenocorticotrophin hormone (ACTH) levels was assessed in serum and brain-derived-neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and nerve growth factor (NGF) protein levels were assessed in prefrontal cortex, hippocampus and amygdala. We observed that maternal deprivation increased immobility time, and decreased climbing time, without affecting locomotor activity. ACTH circulating levels were increased in maternal deprived rats. Additionally, BDNF protein levels were reduced in the amygdala and NT-3 and NGF were reduced in both hippocampus and amygdala in maternal deprived rats, compared to control group. In conclusion, our results support the idea that behavioral, ACTH circulating levels and neurotrophins levels altered in maternal deprivation model could contribute to stress-related diseases, such as depression.

Correlation between behavioral deficits and decreased brain-derived neurotrofic factor in neonatal meningitis

We investigated the correlation between memory impairment and hippocampal brain-derived neurotrophic factor (BDNF) levels in adult rats submitted to experimental meningitis (Streptococcus pneumoniae) in the neonatal period. Sixty days after inoculation the animals were submitted to the behavior tasks and hippocampal BDNF protein were evaluated. In the meningitis group, there was impairment in habituation and avoidance memory and a decrease in the BDNF levels. The decrease in hippocampal BDNF levels correlated to impairment in memory in adult animals submitted to experimental meningitis in the neonatal period.

A kinetic study of the cytokine/chemokines levels and disruption of blood-brain barrier in infant rats after pneumococcal meningitis

Bacterial meningitis is an inflammation of the meninges and subarachnoid space that occurs in response of bacteria. Young children are particularly vulnerable to bacterial meningitis, two thirds of meningitis deaths in low-income countries occur among children under the age of fifteen. The main bacterial pathogens causing meningitis beyond the neonatal period are Streptococcus pneumoniae, Haemophilus influenza type b and Neisseria meningitidis. Therefore, the aim of this study is to evaluate the kinetic and the levels of TNF-α, IL-1β, IL-6, IL-10 and CINC-1 in different brain regions as well as the blood-brain barrier permeability after meningitis induced by S. pneumoniae in infant Wistar rats. The animals underwent a magna cistern tap receiving either 10μL sterile saline as a placebo or an equivalent volume of a S. pneumoniae suspension at the concentration 1×10(6)CFU/mL. The animals were killed at different times after induction. The brain was removed and the hippocampus and the cortex were isolated and used for the determination of cytokine/chemokine levels and blood-brain barrier permeability. The cerebrospinal fluid was obtained by puncture of the cisterna magna to TNF-α and IL-1β analysis. In the hippocampus, the CINC-1 and IL-1β levels were found increased at 6h, 12h and 24h after pneumococcal meningitis induction. In the cortex the levels of the CINC-1 were increased at 6h, 12h and 24h. The IL-1β and TNF-α were increased at 12h and 24h. The level of IL-6 was increased only after 24h after pneumococcal meningitis induction. In cerebrospinal fluid, the TNF-α was increased at 12h, 24h and IL-1 was increased at 24h after S. pneumoniae induction. The blood-brain barrier breakdown in hippocampus and cortex were observed at 12h until 24h during meningitis. In conclusion, a peak of pro-inflammatory cytokine/chemokine is associated with disruption of the blood-brain barrier in infants with pneumococcal meningitis.

Lamotrigine treatment reverses depressive-like behavior and alters BDNF levels in the brains of maternally deprived adult rats

Lamotrigine is an anticonvulsant and has an antiglutamatergic action, which may contribute to its antidepressant effects, since glutamate has been linked to depression. The purpose of the present study was to investigate the behavioral and molecular effects of lamotrigine treatment in maternally deprived rats. To this aim, deprived and non-deprived male rats were treated with lamotrigine (20 mg/kg) once a day for 14 days during their adult phase. Their behavior was then assessed in the forced swimming and open field tests. In addition to this, the BDNF and NGF levels were assessed in the prefrontal cortex, hippocampus and amygdala. In the course of this study we demonstrated that maternally deprived rats treated with saline and lamotrigine showed an increase in their immobility time and a decrease in the climbing and swimming times when compared with non-deprived rats treated with saline alone. Treatment with lamotrigine reversed the increase in the immobility time in the deprived rats. The BDNF levels were decreased in the amygdala in deprived rats treated with saline, and treatment with lamotrigine reversed this decrease. The NGF levels were decreased in the hippocampus in deprived rats treated with saline, but treatment with lamotrigine did not reverse this decrease. In conclusion, lamotrigine showed antidepressant effects in the forced swimming test, and it presented positive effects on the BDNF protein levels in the amygdala of maternally deprived rats.

Dexamethasone Treatment Reverses Cognitive Impairment but Increases Brain Oxidative Stress in Rats Submitted to Pneumococcal Meningitis

Pneumococcal meningitis is associated with a significant mortality rate and neurologic sequelae. The animals received either 10 μL of saline or a S. pneumoniae suspension and were randomized into different groups: sham: placebo with dexamethasone 0.7 mg/kg/1 day; placebo with dexamethasone 0.2 mg/kg/7 days; meningitis groups: dexamethasone 0.7 mg/kg/1 day and dexamethasone 0.2 mg/kg/7 days. Ten days after induction we evaluated memory and oxidative stress parameters in hippocampus and cortex. In the step-down inhibitory avoidance task, we observed memory impairment in the meningitis group with dexamethasone 0.2 mg/kg/7 days. The lipid peroxidation was increased in hippocampus in the meningitis groups with dexamethasone and in cortex only in the meningitis group with dexamethasone 0.2 mg/kg/7 days. The protein carbonyl was increased in hippocampus in the meningitis groups with dexamethasone and in cortex in the meningitis groups with and without dexamethasone. There was a decrease in the proteins integrity in hippocampus in all groups receiving treatment with dexamethasone and in cortex in all groups with dexamethasone (0.7 mg/kg/1 day). The mitochondrial superoxide was increased in the hippocampus and cortex in the meningitis group with dexamethasone 0.2 mg/kg/7 days. Our findings demonstrate that dexamethasone reverted cognitive impairment but increased brain oxidative stress in hippocampus and cortex in Wistar rats ten days after pneumococcal meningitis induction.

Effect of maternal deprivation on acetylcholinesterase activity and behavioral changes on the ketamine-induced animal model of schizophrenia

Maternal deprivation has been associated with physiological and developmental changes that may be related to an increased risk for childhood and adult neuropsychiatric diseases. A growing number of studies demonstrated the importance of childhood experiences in the development of psychosis and schizophrenia in adulthood. Therefore, the present study investigated different behavior responses in rats following maternal deprivation and/or ketamine treatment in adulthood. Male rats were subjected to maternal deprivation for 180 min from postnatal day-01 to postnatal day-10. We evaluated locomotor activity, avoidance task and social interaction of adult male rats deprived or not deprived that were administered with saline or acute subanesthetic doses of ketamine (5, 15 and 25 mg/kg, i.p.). Our results show that only ketamine (25 mg/kg, i.p.) treatment in the adult rats lead to hyperlocomotion but not ketamine (5 and 15 mg/kg) and maternal deprivation alone. However, maternally deprived rats treated with ketamine (5 mg/kg) induced hyperlocomotion. Additionally, ketamine (25 mg/kg) and maternal deprivation alone induced cognitive deficit in the avoidance task. Rats deprived of and treated with ketamine (5, 15 and 25 mg/kg) also lead to memory deficit. Moreover, ketamine (25 mg/kg) and maternal deprivation alone increased latency to start social behavior. However, ketamine (5 mg/kg) and maternal deprivation lead to an increase of latency to start social behavior. Biochemistry data showed that all doses of ketamine and ketamine plus maternal deprivation increased the acetylcholinesterase (AChE) activity in the prefrontal cortex, hippocampus and striatum. The major doses of ketamine associated with maternal deprivation induced a major increase of AChE activity. Together, our results suggest that animals subjected to maternal deprivation had an increased risk for schizophrenia-like behavior and cholinergic alteration.

Central Nervous System Involvement in the Animal Model of Myodystrophy

Congenital muscular dystrophies present mutated gene in the LARGE mice model and it is characterized by an abnormal glycosylation of α-dystroglycan (α-DG), strongly implicated as having a causative role in the development of central nervous system abnormalities such as cognitive impairment seen in patients. However, the pathophysiology of the brain involvement remains unclear. Therefore, the objective of this study is to evaluate the oxidative damage and energetic metabolism in the brain tissue as well as cognitive involvement in the LARGE(myd) mice model of muscular dystrophy. With this aim, we used adult homozygous, heterozygous, and wild-type mice that were divided into two groups: behavior and biochemical analyses. In summary, it was observed that homozygous mice presented impairment to the habituation and avoidance memory tasks; low levels of brain-derived neurotrophic factor (BDNF) in the prefrontal cortex, hippocampus, cortex and cerebellum; increased lipid peroxidation in the prefrontal cortex, hippocampus, striatum, and cerebellum; an increase of protein peroxidation in the prefrontal cortex, hippocampus, striatum, cerebellum, and cortex; a decrease of complex I activity in the prefrontal cortex and cerebellum; a decrease of complex II activity in the prefrontal cortex and cerebellum; a decrease of complex IV activity in the prefrontal cortex and cerebellum; an increase in the cortex; and an increase of creatine kinase activity in the striatum and cerebellum. This study shows the first evidence that abnormal glycosylation of α-DG may be affecting BDNF levels, oxidative particles, and energetic metabolism thus contributing to the memory storage and restoring process.

Acetylcholinesterase activity in the rat brain after pneumococcal meningitis

Pneumococcal meningitis is a life‐threatening disease characterized by acute purulent infection of the meninges causing neuronal injury, cortical necrosis and hippocampal apoptosis. Cholinergic neurons and their projections are extensively distributed throughout the central nervous system. The aim of this study was to assess acetylcholinesterase activity in the rat brain after pneumococcal meningitis. In the hippocampus, frontal cortex and cerebrospinal fluid, acetylcholinesterase activity was found to be increased at 6, 12, 24, 48 and 96 hr without antibiotic treatment, and at 48 and 96 hr with antibiotic treatment. Our data suggest that acetylcholinesterase activity could be related to neuronal damage induced by pneumococcal meningitis.

Increased Na+,K+‐ATPase activity in the rat brain after meningitis induction by Streptococcus pneumoniae

Barichello T, Generoso JS, Cipriano AL, Casagrande R, Collodel A, Savi GD, Scherer EBS, Kolling J, Wyse ATS. Increase Na+,K+-ATPase activity in the rat brain after meningitis induction by Streptococcus pneumoniae. Background: Pneumococcal meningitis is the most severe infection of the central nervous system with a mortality rate up to 20% and an adverse neurological result in up to 50% of survivors. A complicated series of interactions among the host immune response and oxidants seems to be responsible for meningitis associated brain dysfunctions. Na+,K+-ATPase is an essential enzyme responsible for generating and maintaining the membrane potential necessary for neural excitability, however, the Na+,K+-ATPase activity is altered in several illness; Objective: The aim of this study is to evaluate the Na+,K+-ATPase activity in hippocampus and cortex of the rats submitted to pneumococcal meningitis. Methods: Animals received 10 µl sterile saline as a placebo or an equivalent volume of Streptococcus pneumoniae to the concentration of 5 × 109cfu/ml and were killed at 24, 48, 72 and 96 h after meningitis induction. The brain structures, hippocampus and cortex, were immediately isolated on dry ice and stored at −80°C to analyse Na+,K+-ATPase activity. Results: In the hippocampus, we verified the increase of Na+,K+-ATPase activity at 48, 72 and 96 h (p < 0.05) and in the cortex at 24 h (p < 0.05) after pneumococcal meningitis induction. Conclusion: The Na+,K+-ATPase activity is under the control of a diversity of intracellular messengers that are able to modulate the function of the particular isozymes in a precise way. Furthermore, we verified that pneumococcal meningitis increased the Na+,K+-ATPase activity in hippocampus and cortex; this increase can be correlated with a compensatory mechanism in illness pathophysiology.