Single Dose Of Valproic Acid Research Articles

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

Aim and objectiveThe purpose of the study is to determine the neuroprotective effect of capric acid on sodium valproate-induced model of autism. MethodsIn 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. ResultsValproic 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. ConclusionThe 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.

Syringic acid alleviates valproic acid induced autism via activation of p38 mitogen-activated protein kinase: Possible molecular approach.

Autism spectrum disorder (ASD) is a multifactorial neurodevelopmental disorder characterized by restrictive and repetitive behavior followed by impairment in social, verbal, and non-verbal interaction and communication. Valproic acid (VPA) is a well-known anti-epileptic drug, but its prenatal exposure to animals causes social impairment, neurotransmitters imbalance, and neuroinflammation with ASD-like phenotypes. Syringic acid (SA) is a polyphenolic compound with anti-inflammatory, anti-apoptotic, antioxidant, and neuromodulator activity. The purpose of study was to investigate the protective effect of Syringic acid (SA) in prenatal VPA-treated rats through behavioral, neuroinflammation, oxidative stress, neurotransmitters, neuronal integrity, and apoptotic marker. Single dose of VPA was administered 600 mg/kg, i.p. on a gestational day (GD) 12th and SA was administrated from PnD 26th to 54th at the dose of 25, 50, and 100 mg/kg, p.o. On PnD 56th behavioral parameters (Pain sensitivity, open field test, narrow beam walks test and social impairment test) were performed and all animals were sacrificed, and brain tissue was isolated for oxidative stress (GSH, CAT, and LPO), neuroinflammation (TNF-α and IL-6) and neurotransmitters (GABA and Glutamate), histopathology (H&E, Nissl), immunohistochemistry (p38 MAPK) analysis. Rat treated with SA dose-dependently prevented behavioral alteration, restored antioxidant enzymes, neurotransmitters level, decreased neuroinflammatory markers, and improved neuronal integrity. Furthermore, immunohistochemistry confirmed the reduced p38 MAPK marker expression by SA in VPA induced autistic behavior.

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.

Attenuation of Autism-like Behaviors by an Anthocyanin-Rich Extract from Portuguese Blueberries via Microbiota-Gut-Brain Axis Modulation in a Valproic Acid Mouse Model.

Autism Spectrum Disorders (ASDs) are a group of neurodevelopmental pathologies whose current treatment is neither curative nor effective. Anthocyanins are naturally occurring compounds abundant in blueberries and in other red fruits which have been shown to be successful in the treatment of several neurological diseases, at least in in vitro and in vivo disease models. The aim of the present work was to study the ability of an anthocyanin-rich extract (ARE) obtained from Portuguese blueberries to alleviate autism-like symptoms in a valproic acid (VPA) mouse model of ASD and to get insights into the underlying molecular mechanisms of such benefits. Therefore, pregnant BALB/c females were treated subcutaneously with a single dose of VPA (500 mg/kg) or saline on gestational day 12.5. Male offspring mice were orally treated with the ARE from Portuguese blueberries (30 mg/kg/day) or the vehicle for three weeks, and further subjected to behavioral tests and biochemical analysis. Our data suggested that the ARE treatment alleviated autism-like behaviors in in utero VPA-exposed mice and, at the same time, decreased both neuroinflammation and gut inflammation, modulated the gut microbiota composition, increased serotonin levels in cerebral prefrontal cortex and gut, and reduced the synaptic dysfunction verified in autistic mice. Overall, our work suggests that anthocyanins extracted from Portuguese blueberries could constitute an effective strategy to ameliorate typical autistic behaviors through modulation of the microbiota–gut–brain axis.

A single dose of valproic acid improves neurologic recovery and decreases brain lesion size in swine subjected to an isolated traumatic brain injury.

We lack specific treatments for traumatic brain injury (TBI), which remains the leading cause of trauma-related morbidity and mortality. Treatment with valproic acid (VPA) improves outcomes in models of severe TBI with concurrent hemorrhage. However, it is unknown if VPA will have similar benefits after isolated nonlethal TBI, which is the more common clinical scenario. The goal of this study was to evaluate the effect of VPA treatment in a preclinical isolated TBI swine model on neurologic outcomes and brain lesion size and to perform detailed pharmacokinetic analyses for a future clinical trial. Yorkshire swine (n = 10; 5/cohort) were subjected to TBI (8-mm controlled cortical impact). An hour later, we randomized them to receive VPA (150 mg/kg) or saline placebo (control). Neuroseverity scores were assessed daily (0 [normal] to 36 [comatose]), brain lesion size was measured on postinjury 3, and serial blood samples were collected for pharmacokinetic studies. Physiologic parameters and laboratory values were similar in both groups. Valproic acid-treated animals demonstrated significantly better neuroseverity scores on postinjury 1 (control, 9.2 ± 4.4; VPA, 0 ± 0; p = 0.001). Valproic acid-treated animals had significantly smaller brain lesion sizes (mean volume in microliter: control, 3,130 ± 2,166; VPA, 764 ± 208; p = 0.02). Pharmacokinetic data confirmed adequate plasma and tissue levels of VPA. In this clinically relevant model of isolated TBI, a single dose of VPA attenuates neurological impairment and decreases brain lesion size.

Post-stroke Delivery of Valproic Acid Promotes Functional Recovery and Differentially Modifies Responses of Peri-Infarct Microglia.

The specific role of peri-infarct microglia and the timing of its morphological changes following ischemic stroke are not well understood. Valproic acid (VPA) can protect against ischemic damage and promote recovery. In this study, we first determined whether a single dose of VPA after stroke could decrease infarction area or improve functional recovery. Next, we investigated the number and morphological characteristic of peri-infarct microglia at different time points and elucidated the mechanism of microglial response by VPA treatment. Male Sprague-Dawley rats were subjected to distal middle cerebral artery occlusion (dMCAo) for 90 min, followed by reperfusion. Some received a single injection of VPA (200 mg/kg) 90 min after the induction of ischemia, while vehicle-treated animals underwent the same procedure with physiological saline. Infarction volume was calculated at 48 h after reperfusion, and neurological symptoms were evaluated. VPA didn’t significantly reduce infarct volume but did ameliorate neurological deficit at least partially compared with vehicle. Meanwhile, VPA reduced dMCAo-induced elevation of IL-6 at 24 h post-stroke and significantly decreased the number of CD11b-positive microglia within peri-infarct cortex at 7 days. Morphological analysis revealed that VPA therapy leads to higher fractal dimensions, smaller soma size and lower circularity index of CD11b-positive cells within peri-infarct cortex at both 2 and 7 days, suggesting that VPA has core effects on microglial morphology. The modulation of microglia morphology caused by VPA might involve HDAC inhibition-mediated suppression of galectin-3 production. Furthermore, qPCR analysis of CD11b-positive cells at 3 days post-stroke suggested that VPA could partially enhance M2 subset polarization of microglia in peri-infarct cortex. Analysis of VPA-induced changes to gene expressions at 3 days post-stroke implies that these alternations of the biomarkers and microglial responses are implicated in the upregulation of wound healing, collagen trimmer, and extracellular matrix genes within peri-infarct cortex. Our results are the first to show that a low dose of VPA promotes short-term functional recovery but does not alter infarct volume. The decreases in the expression of both IL-6 and galectin-3 might influence the morphological characteristics and transcriptional profiles of microglia and extracellular matrix remodeling, which could contribute to the improved recovery.

Valproic Acid Protects Against Acute Kidney Injury in Hemorrhage and Trauma

Trauma is the leading cause of death among young people. These patients have a high incidence of kidney injury, which independently increases the risk of mortality. As valproic acid (VPA) treatment has been shown to improve survival in animal models of lethal trauma, we hypothesized that it would also attenuate the degree of acute kidney injury. We analyzed data from two separate experiments where swine were subjected to lethal insults. Model 1: hemorrhage (50% blood volume hemorrhage followed by 72-h damage control resuscitation).Model 2: polytrauma (traumatic brain injury, 40% blood volume hemorrhage, femur fracture, rectus crush and grade V liver laceration).Animals were resuscitated with normal saline (NS) +/- VPA 150 mg/kg after a 1-h shock phase in both models (n=5-6/group). Serum samples were analyzed for creatinine (Cr) using colorimetry on a Liasys 330 chemistry analyzer. Proteomic analysis was performed on kidney tissue sampled at the time of necropsy. VPA treatment significantly (P < 0.05) improved survival inboth models. (Model 1: 80% vs 20%; Model 2: 83% vs. 17%).Model 1(Hemorrhage alone): Cr increased from a baseline of 1.2 to 3.0 in NS control animals (P < 0.0001) 8 h after hemorrhage, whereas it rose only to 2.1 in VPA treated animals (P=0.004). Model 2 (Polytrauma): Cr levels increased from baseline of 1.3 to 2.5 mg/dL (P=0.01) in NS control animals 4 h after injury but rose to only 1.8 in VPA treated animals (P=0.02).Proteomic analysis of kidney tissue identified metabolic pathways were most affected by VPA treatment. A single dose of VPA (150 mg/kg) offers significant protection against acute kidney injury in swine models of polytrauma and hemorrhagic shock.

Dose optimization of valproic acid in a lethal model of traumatic brain injury, hemorrhage, and multiple trauma in swine.

Trauma is a leading cause of death, and traumatic brain injury is one of the hallmark injuries of current military conflicts. Valproic acid (VPA) administration in high doses (300-400 mg/kg) improves survival in lethal trauma models, but effectiveness of lower doses on survival is unknown. This information is essential for properly designing the upcoming clinical trials. We, therefore, performed the current study to determine the lowest dose at which VPA administration improves survival in a model of lethal injuries. Swine were subjected to traumatic brain injury (10-mm cortical impact), 40% blood volume hemorrhage, and multiple trauma (femur fracture, rectus crush, and Grade V liver laceration). After 1 hour of shock, animals were randomized (n = 6/group) to four groups: normal saline (NS) resuscitation; or NS with VPA doses of 150 mg/kg (VPA 150) or 100 mg/kg (VPA 100) administered over 3 hours or 100 mg/kg over 2 hours (VPA 100 over 2 hours). Three hours after shock, packed red blood cells were given, and animals were monitored for another 4 hours. Survival was assessed using Kaplan-Meier and log-rank test. Without resuscitation, all of the injured animals died within 5 hours. Similar survival rates were observed in the NS (17%) and VPA 100 (0%) resuscitation groups. Survival rates in the 100-mg/kg VPA groups were significantly (p < 0.05) better when it was given over 2 hours (67%) compared to 3 hours (0%). 83% of the animals in the VPA 150 group survived, which was significantly higher than the NS and VPA 100 over 3 hours groups (p < 0.05). A single dose of VPA (150 mg/kg) significantly improves survival in an otherwise lethal model of multiple injuries. This is a much lower dose than previously shown to have a survival benefit and matches the dose that is tolerated by healthy human subjects with minimal adverse effects. Therapeutic, level V.

Rapid valproic acid-induced modulation of the traumatic proteome in a porcine model of traumatic brain injury and hemorrhagic shock

BackgroundHistone deacetylase inhibitors such as valproic acid (VPA) improve survival in lethal models of hemorrhagic shock and polytrauma. Although VPA is known to modulate transcription, its ability to reduce mortality within minutes of administration suggests involvement of a rapid, posttranslational mechanism. We hypothesized that VPA treatment would cause proteomic changes within minutes of treatment including quantitative and/or posttranslational differences in structural and/or effector proteins. Materials and methodsWe used a porcine model of traumatic brain injury (computer-controlled cortical impact, 12 mm depth) and hemorrhagic shock (40% hemorrhage). Animals were kept in shock for 2 h and randomized to two groups (n = 3): normal saline (volume = 3:1 hemorrhage volume) or normal saline + VPA (150 mg/kg, single dose). Peripheral blood mononuclear cells were collected at baseline, postshock, and postresuscitation. Intracellular protein profiles were assessed using 1 dimensional gel electrophoresis, liquid chromatography, mass spectrometry, and analyzed with Ingenuity Pathway Analysis software. ResultsAnimals treated with VPA demonstrated significant proteomic changes. Quantitative differences were found in over 200 proteins including effector, regulatory, and structural proteins in critical cell signaling pathways. Posttranslational modification analysis demonstrated differential VPA-induced acetylation of lysine residues in histone and nonhistone proteins. Pathway analysis correlated these changes with significant increases in numerous prosurvival and cytoskeletal intracellular pathways, including Rho GTPase signaling (P = 1.66E-11), integrin signaling (P = 4.19E-21), and a decrease in Rho guanosine nucleotide dissociation inhibitor signaling (P = 4.83E-12). ConclusionsIn a porcine model of severe injuries, a single dose of VPA is associated with protective changes in the proteome that are measurable within minutes of treatment.

Neuroprotective Effect of Resveratrol on Valproic Acid Induced Oxidative Stress Autism in Swiss Albino Mice

The present research work is aimed to investigate the anti-oxidant/neuroprotective role of Resveratrol in reversing the valproic acid induced autism in postnatal swiss albino mice. Separate 13 day old/ Post natal day (PND) 13 swiss albino mice of either sex into 5 groups, each group consists of six mice of either sex, groups namely Group I - Control, Group II - Resveratrol, Group III - Negative control, Group IV and V - Resveratrol treatment groups. On PND 14 administer single dose of Valproic acid (VPA) or Sodium Valproate (400 mg/kg, subcutaneously) to III, IV and V groups to induce autism. Treatment is given in two doses 10 mg/kg, intraperitoneally (i.p) as Low dose and 40 mg/kg, i.p as High dose from the 13th day to the end of study. Assessment of autism is done by different behavioral screening methods during PND 14 to 40. Treatment with resveratrol significantly decline the autism symptoms compared with negative control. At the end of study on PND 41 all the animals were sacrificed to assess the biochemical estimations like Anticholinesterase enzyme, Total Protein, antioxidant enzyme (Catalase, Superoxide and Glutathione) activity and cerebellar histopathological examination. Treatment with Resveratrol has shown a significant beneficial difference on behavioral alterations, oxidative markers, neurotransmitters, and restoration of the altered purkinje cells of autism. This research work we conclude that resvertrol have a potent anti-oxidant, neuroprotective, anxiolytic, learning and memory enhancing agent against valproic acid induced autism.

Metabolite profiling of whole murine embryos reveals metabolic perturbations associated with maternal valproate-induced neural tube closure defects.

Valproic acid (VPA) is prescribed therapeutically for multiple conditions, including epilepsy. When taken during pregnancy, VPA is teratogenic, increasing the risk of several birth and developmental defects including neural tube defects (NTDs). The mechanism by which VPA causes NTDs remains controversial and how VPA interacts with folic acid (FA), a vitamin commonly recommended for the prevention of NTDs, remains uncertain. We sought to address both questions by applying untargeted metabolite profiling analysis to neural tube closure (NTC) stage mouse embryos. Pregnant SWV dams on either a 2 ppm or 10 ppm FA supplemented diet were injected with a single dose of VPA on gestational day E8.5. On day E9.5, the mouse embryos were collected and evaluated for NTC status. Liquid chromatography coupled to mass spectrometry metabolomics analysis was performed to compare metabolite profiles of NTD-affected VPA-exposed whole mouse embryos with profiles from embryos that underwent normal NTC from control dams. NTDs were observed in all embryos from VPA-treated dams and penetrance was not diminished by dietary FA supplementation. The most profound metabolic perturbations were found in the 10ppm FA VPA-exposed mouse embryos, compared with the other three treatment groups. Affected metabolites included amino acids, nucleobases and related phosphorylated nucleotides, lipids, and carnitines. Maternal VPA treatment markedly perturbed purine and pyrimidine metabolism in E9.5 embryos. In combination with a high FA diet, VPA treatment resulted in gross metabolic changes, likely caused by a multiplicity of mechanisms, including an apparent disruption of mitochondrial beta-oxidation. Birth Defects Research 109:106-119, 2017. © 2016 Wiley Periodicals, Inc.

Single-dose intravenous administration of antiepileptic drugs induces rapid and reversible remodeling in the brain: Evidence from a voxel-based morphometry evaluation of valproate and levetiracetam in rhesus monkeys

Effects of the long-term use of antiepileptic drugs (AEDs) on the brains of patients with epilepsy have been previously reported. The aim of this study was to determine the rapid brain structure remodeling induced by single-dose intravenous AED administration that rules out the potential effects of epilepsy. Ten rhesus monkeys were randomly divided into two groups and were intravenously administered a single dose of valproic acid (VPA) or levetiracetam (LEV) at treatment dosages. Magnetic resonance imaging (MRI) data were recorded from every subject prior to AED administration and at 2h and 1 week after administration. Using optimized voxel-based morphometry (VBM) analysis, we measured changes in regional gray matter volume (GMV) and white matter volume (WMV) in each group over time following medication and directly compared the differences between the two groups. Both AEDs induced brain volume alterations at 2h after their administration, but these changes had reverted at 1 week. The VPA group exhibited increased GMV in the right geniculate nucleus and the right pulvinar, whereas the LEV group exhibited WMV reductions in the right pulvinar, the right parietal lobe and the right occipital lobe. Directly compared with the LEV group, the VPA group exhibited a temporally constant GMV increase in the bilateral temporal cortex and a WMV reduction in the left pedunculus cerebri. Single-dose intravenous administration of a level of VPA or LEV that mimics clinical use is associated with rapid and reversible VBM-detected GMV or WMV alterations in rhesus monkeys. This finding may provide new insights into the understanding of AED-induced brain structure remodeling and may contribute to our understanding of the brain-level mechanisms and targets of AED action.

Combined intraoperative administration of a histone deacetylase inhibitor and a neurokinin-1 receptor antagonist synergistically reduces intra-abdominal adhesion formation in a rat model

Intra-abdominal adhesions are the most frequent postoperative complication after abdominopelvic surgery. Our laboratory has previously shown that an intraoperative peritoneal lavage containing either the histone deacetylase inhibitor valproic acid (VPA) or a neurokinin-1 receptor antagonist (NK-1RA) reduced adhesions by approximately 50% in a rat model. The objective of this study was to determine whether the combination of these 2 drugs was more effective in reducing adhesions than either alone. Rats underwent laparotomy with creation of peritoneal ischemic buttons to induce adhesions. A single dose of VPA (25mg/kg), NK-1RA (50mg/kg), a combination of both, or 0.9% saline was lavaged intraperitoneally just before wound closure. On postoperative day 7, adhesions were quantified. To investigate early mechanisms of adhesiogenesis, adhesions were created as described and adhesive button tissue was harvested at 30minutes and 3hours postoperatively and fibrinogen and vascular endothelial growth factor (VEGF) protein levels, both indices of peritoneal extravasations, were determined by Western blot analysis. Peritoneal fluid was collected in similar experiments at 30minutes, and 3 and 6hours to measure fibrinolytic activity, an index of the ability of the peritoneum to degrade fibrinous adhesions. The coadministration of VPA plus NK-1RA reduces adhesions by 72.6% relative to saline (P<.001); this reduction was greater than either compound alone (P<.001). Peritoneal fibrinolytic activity was significantly increased at 3 and 6hours postoperatively in animals administered the combination therapy versus saline (P=.01). VPA plus NK-1RA significantly decreased fibrinogen and VEGF protein levels at 3 and 6hours compared with saline controls. These results suggest that a combined pharmacologic approach targeting multiple adhesiogenic pathways provides optimal adhesion prevention.

Circadian variation of Valproic acid pharmacokinetics in mice

Valproic acid (VPA) is currently one of the most commonly used antiepileptic drugs. This study aims to investigate whether VPA pharmacokinetics varied according to circadian dosing-time. A single dose of VPA (350mgkg−1) was administered by intraperitonally (i.p.) route to a total of 132 mice synchronized for 3weeks to 12h light (rest span) and 12h dark (activity span). Four different circadian times (1, 7, 13 and 19 HALO) of drug injection were used (33 mice/circadian time). At each circadian time, blood samples were withdrawn at (0h) and at 0.083, 0.166, 0.25, 0.5, 0.75, 1, 1.25, 1.5, 2 and 3h after VPA injection. Plasma VPA concentrations were determined by an EMIT method.There were no significant differences in Tmax of VPA whatever the circadian-time of injections (Tmax=0.166h). However, there were relevant differences in Cmax between the four circadian groups (p<0.005), it varied between 386±30.86mgL−1 in mice treated at 7 HALO and 824±39.85mgL−1 in mice treated at 19 HALO. The AUC0–∞ was significantly two times higher when VPA was administered at 19 HALO as compared to the injection at 7 HALO. Drug dosing at 7 HALO resulted in highest ClT value: 0.405±0.006Lh−1kg−1, whereas ClT was significantly slower when VPA was administered at 19 HALO (0.157±0.009Lh−1kg−1) (p<0.0001). The AUC0–∞ was significantly 2-fold higher when VPA was administered at 19 HALO (2216.65±138.91mgh−1L−1) as compared to the injection at 7 HALO (864.09±16.82mgh−1L−1) (p<0.0001).Cosinor analysis showed circadian rhythm in different pharmacokinetic parameters. Cmax and AUC0–∞ have a significant circadian rhythm with an acrophase located at 20.16 HALO±0.16h (the middle of the active span) (p<0.001), whereas ClT and Vd showed a significant circadian rhythm with an acrophase located respectively at 7.86 HALO±0.57h and 6.13 HALO±0.07h (the middle of the rest span) (p<0.001).The large circadian variation of VPA pharmacokinetic processes might be involved in the mechanisms of circadian rhythm in murine toxicity since the optimal tolerance corresponded to the time which induces lowest Cmax and AUC values.

Lamotrigine and valproic acid have different effects on motorcortical neuronal excitability

To investigate different cortical effects of lamotrigine and valproic acid, 30 paid healthy adult men were given, in a randomized/blinded fashion on three separate days (separated by a week), either a single dose of lamotrigine 325 mg, or a single dose of valproic acid 1,250 mg, or placebo. Resting motor threshold (RMT), cortical silent period (CSP) and motor evoked potential recruitment curves (RC) were assessed at baseline and 3 h after administration of each medication (or placebo). Lamotrigine caused a significant increase (63.32 vs. 69.25) in the RMT, compared with an insignificant increase following valproic acid (62.50 vs. 63.35), and a decrease (62.60 vs. 62.36) following placebo (F (2,26) = 18.58, P < 0.0001). No significant difference in CSP was found between placebo and drugs (F (2,26) = 0.119, P > 0.05). RCs were significantly suppressed by lamotrigine (t = 2.07, P < 0.05) and enhanced by valproic acid (t = 2.39, P < 0.05). Lamotrigine and valproic acid have different effects on cortical neuronal excitability as demonstrated by TMS.

Valproic Acid I: Time Course of Lipid Peroxidation Biomarkers, Liver Toxicity, and Valproic Acid Metabolite Levels in Rats

A single dose of valproic acid (VPA), which is a widely used antiepileptic drug, is associated with oxidative stress in rats, as recently demonstrated by elevated levels of 15-F(2t)-isoprostane (15-F(2t)-IsoP). To determine whether there was a temporal relationship between VPA-associated oxidative stress and hepatotoxicity, adult male Sprague-Dawley rats were treated ip with VPA (500 mg/kg) or 0.9% saline (vehicle) once daily for 2, 4, 7, 10, or 14 days. Oxidative stress was assessed by determining plasma and liver levels of 15-F(2t)-IsoP, lipid hydroperoxides (LPO), and thiobarbituric acid reactive substances (TBARs). Plasma and liver 15-F(2t)-IsoP were elevated and reached a plateau after day 2 of VPA treatment compared to control. Liver LPO levels were not elevated until day 7 of treatment (1.8-fold versus control, p < 0.05). Liver and plasma TBARs were not increased until 14 days (2-fold vs. control, p < 0.05). Liver toxicity was evaluated based on serum levels of alpha-glutathione S-transferase (alpha-GST) and by histology. Serum alpha-GST levels were significantly elevated by day 4, which corresponded to hepatotoxicity as shown by the increasing incidence of inflammation of the liver capsule, necrosis, and steatosis throughout the study. The liver levels of beta-oxidation metabolites of VPA were decreased by day 14, while the levels of 4-ene-VPA and (E)-2,4-diene-VPA were not elevated throughout the study. Overall, these findings indicate that VPA treatment results in oxidative stress, as measured by levels of 15-F(2t)-IsoP, which precedes the onset of necrosis, steatosis, and elevated levels of serum alpha-GST.

Early changes in hepatic redox homeostasis following treatment with a single dose of valproic acid

Changes in reduced glutathione (GSH) and pyridine nucleotide phosphate levels as well as in the activities of the glutathione peroxidase-reductase system and glucose-6-phosphate dehydrogenase have been studied in rats after a single i. p. administration of various doses of valproic acid (VPA). GSH level decreased in a dose-dependent relation. At the end of 180min GSH levels either returned to control limits (lower doses) or showed a tendency to normalize (higher doses). GSH loss was paralleled by the reduction in glutathione reductase activity. A significant NADPH reduction was also seen after animal exposure to high VPA doses. At the end of 180 min a maximal NADPH decrease was reached. The activities of both glutathione peroxidase and glucose-6-phosphate dehydrogenase were suppressed irrespective of whether animals were given low or high VPA doses.

Lesions and repair of cells of maternal mice after valproic acid (VPA) treatment on day 8 of pregnancy: An enzyme histochemical analysis

Mice received a single teratogenic dose of the antiepileptic drug valproic acid (VPA; 500 mg/kg i.p.) on 8th d of pregnancy. The effects of VPA were studied primarily by enzyme histochemical means over a period of 48 h. Plasma membrane-associated hydrolases were more affected than lysosome-associated ones. Lesions were not found in the spleen, but a slight response, without morphological damages, was observed in the lung and thymus. Comparatively more severe injuries, which were not accompanied by clear-cut structural changes either, occurred in the liver. The most severe damages including morphological lesions were noticed especially in the proximal tubules of the kidney. The first damages were already seen after 3 h and concerned primarily the liver. After 12 h, a maximal response to VPA was detected in all organs. Repair of most of the enzymatic lesions set in after 24 h. After 48 h, lesions were not longer seen in the lung and thymus. In contrast, enzymatically and morphologically injured proximal renal tubules could still be found after this period as a response to a single dose of VPA; in the liver only enzymatic lesions were present at this stage.

The fate of electron opaque tracers (horseradish peroxidase and lanthanum chloride) during valproic acid-induced choleresis.

Horseradish peroxidase (HRP) and lanthanum chloride (LaCl3) are useful tools for, respectively, the study of vesicular transport through the hepatocyte and the study of the permeability of junctional complexes. These tracers have been used to detect the changes associated with the choleresis independent of bile acids induced by valproic acid (VPA) in rats. The animals were given a single dose of VPA (600 mg/kg, ip). HRP (100 mg/kg) or 5 mM LaCl3 were given intraportally after 1 h, when bile flow had increased twofold. The excretion of HRP in bile was measured colorimetrically up to 2 h after HRP. Ultrastructural morphometry was conducted on liver of intact rats taken from 1 to 40 min after HRP. The volume density (VD) of HRP-containing vesicles and of HRP-containing multivesicular bodies (MVB) was counted. In VPA-treated rats, HRP appeared in bile with a peak showing at 5 min against 20 min in controls, but the total amount of HRP excreted was less than in controls. The intrahepatocytic vesicular transport of HRP was also modified, showing a peak at 3 min in VPA-treated rats compared to 10 min in controls, together with a decreased VD of pericanalicular vesicles. This was accompanied by an increase of HRP-containing MVB, already evident at 5 min.(ABSTRACT TRUNCATED AT 250 WORDS)

Early structural and functional changes in liver of rats treated with a single dose of valproic acid.

Valproic acid (VPA) is a simple fatty acid largely used as anticonvulsivant agent. Side effects are uncommon, but cases of fatal hepatic failure have been reported. To elucidate the mechanism of VPA-induced hepatotoxicity, the functional and structural changes associated with administration of sodium valproate (NaVPA) to rats (200 or 600 mg per kg, i.p.) were analyzed. NaVPA produced an immediate, dose-dependent and prolonged increase in bile salt-independent bile flow with a decrease in biliary cholesterol and phospholipid output. At 3 and 5 hr, marked ultrastructural changes were evident in hepatocytes, including formation of autophagic vacuoles engulfing altered mitochondria and occasionally peroxisomes. A modest accumulation of lipoprotein particles was evident at 5 hr in the Golgi cisternae. Twelve-hour samples appeared normal. Bile canaliculi and junctional complexes remained unaltered throughout. The changes observed differ from those previously reported with other hydrocholeretics, such as diethylmaleate; they are likely related to hepatic biotransformation of VPA, which undergoes beta and omega-oxidation, and glucuronidation. While VPA-induced choleresis reflects the physiological osmotic effect of the glucuronide excreted in bile, the ultrastructural changes likely reflect interference by VPA with beta-oxidation of endogenous fatty acids and temporary accumulation of transformation products in the mitochondrial matrix.