SE Rats Research Articles

Exploring the effect of 6-BIO and sulindac in modulation of Wnt/β-catenin signaling pathway in chronic phase of temporal lobe epilepsy

The prospective involvement of the Wnt/β-catenin signaling pathway in epilepsy, with the proposed therapeutic uses of its modulators, has been suggested; however, comprehensive knowledge in this regard is currently limited. Despite postulations about the pathway's significance and treatment potential, a systematic investigation is required to better understand its implications in chronic epilepsy. We investigated the role of key proteins like β-catenin, GSK-3β, and their modulators sulindac and 6-BIO, in Wnt/β-catenin pathway during chronic phase of temporal lobe epilepsy. We also evaluated the role of modulators in seizure score, seizure frequency and neurobehavioral parameters in temporal lobe epilepsy. We developed status epilepticus model using lithium-pilocarpine. The assessment of neurobehavioral parameters was done followed by histopathological examination and immunohistochemistry staining of hippocampus as well as RT-qPCR and western blotting to analyse gene and protein expression. In SE rats, seizure score and frequency were significantly high compared to control rats, with notable changes in neurobehavioral parameters and neuronal damage observed in hippocampus. Our study also revealed a substantial upregulation of the Wnt/β-catenin pathway in chronic epilepsy, as evidenced by gene and protein expression studies. Sulindac emerged as a potent modulator, reducing seizure score, frequency, neuronal damage, apoptosis, and downregulating the Wnt/β-catenin pathway when compared to 6-BIO. Our findings emphasize the potential of GSK-3β and β-catenin as promising drug targets for chronic temporal lobe epilepsy, offering valuable treatment options for chronic epilepsy. The promising outcomes with sulindac encourages further exploration in clinical trials to assess its therapeutic potential.

Exposure to an enriched environment exerts anxiolytic effects in Sardinian alcohol-preferring rats

Exposure to an enriched environment (EE) has been reported to generate multiple beneficial effects in rodents, including – among the many – amelioration of anxiety-related behaviors. The present study investigated whether living in an EE produced anxiolytic effects also in selectively bred Sardinian alcohol-preferring (sP) rats. The relevance of this research question relied on two factors: sP rats displayed an inherent, high anxiety-like state under different experimental conditions; exposure to EE reduced operant, oral alcohol self-administration in sP rats. Starting from weaning, male sP rats were kept under 3 different housing conditions: impoverished environment (IE; single housing with no environmental enrichment); standard environment (SE; 3 rats/cage with no environmental enrichment); EE (6 rats/cage with various elements of environmental enrichment). At the age of approximately 80 days, rats were exposed to an elevated plus maze test for assessment of anxiety-related behaviors. Compared to IE and SE rats, EE rats displayed higher basal levels of exploratory activity (i.e., increased number of entries into closed arms). Compared to IE and SE rats, EE rats also displayed a less “anxious” profile, as suggested by the increase in percent number of entries into open arms (OAs), percent time spent in OAs, number of head dips, and number of end-arm explorations in OAs. These data extend the protective (anxiolytic) effects of EE to a proposed animal model of comorbid alcohol use disorder and anxiety disorders.

Glutathione Peroxidase and Phospholipid Hydroperoxide Glutathione Peroxidase Are Differentially Regulated in Rats by Dietary Selenium

Phospholipid hydroperoxide glutathione peroxidase (PHGPX) and classical glutathione peroxidase (GPX1) are encoded by separate genes with only about 40% amino acid and nucleic acid sequence identity. To determine the response of tissue PHGPX expression to dietary Se level and to compare these responses with those for GPX1, weanling male rats were fed amino acid diets containing from 2 (-Se) to 130 (+Se) µg Se/kg diet or a torula diet containing 5 and 190 µg Se/kg diet as Na2SeO3 for 28 d. Tissues were analyzed for PHGPX and GPX1 activity and mRNA. There was no effect of Se on growth. In -Se rats, GPX1 activity was reduced to 1% in liver and 4–9% in heart, kidney and lung compared with +Se rats; PHGPX activity was reduced only to 25–50% in these four tissues. The Se response curves indicated that the dietary Se requirement to reach plateau liver PHGPX activity was half that required for plateau GPX activity. In -Se rats, liver and heart GPX1 mRNA levels were reduced to 6 and 12%, respectively, whereas PHGPX mRNA was not significantly affected by Se deficiency. Notably, 65 µg Se/kg diet resulted in plateau liver GPX1 mRNA levels but not plateau GPX activity. Testis had the lowest GPX activity and GPX1 mRNA of all tissues examined, but had 15-fold higher PHGPX activity and 45-fold higher PHGPX mRNA levels when compared with liver. There was no significant effect of dietary Se on testis GPX1 and PHGPX mRNA levels. This study demonstrates that these two selenoperoxidases are differentially regulated by dietary Se. Differences in Se regulation of mRNA levels in liver and heart were even more pronounced than for enzyme activity. The lack of any significant effect of reduced dietary Se on PHGPX mRNA levels suggests that there are detailed underlying molecular mechanisms whereby Se status regulates GPX1 mRNA levels but not PHGPX mRNA levels.

Environmental enrichment augments binge-like alcohol drinking in Sardinian alcohol-preferring rats.

Exposure of Sardinian alcohol-preferring (sP) rats to an enriched environment (EE) reduced different aspects of operant alcohol self-administration. The present study was aimed at expanding investigation of the effect of EE exposure upon a model of binge drinking composed of daily 1-h drinking sessions with unpredictable access to multiple alcohol concentrations; binge-like alcohol intakes were observed when the drinking session occurred at the last hours of the dark phase of the light/dark cycle. Starting from postnatal day (PND) 21, male sP rats were kept under three different housing conditions: impoverished environment (IE; single housing with no environmental enrichment); standard environment (SE; 3 rats/cage and no environmental enrichment); EE (6 rats/cage and multiple elements of environmental enrichment). From PND 69, rats were exposed daily to a 1-hour drinking session under the 4-bottle "alcohol (10%, 20%, and 30%, v/v) vs. water" choice regimen, during the dark phase, and with timing of alcohol exposure changed each day. In all three rat groups (IE, SE, and EE), alcohol intake increased progressively as the drinking session moved from the first to last hours of the dark phase. The slope of the regression line was steeper in EE than IE and SE rats, suggestive of higher intakes of alcohol in EE than IE and SE rats when the drinking session occurred over the last hours of the dark phase. These results are discussed hypothesizing that the stressful attributes of alcohol expectation were potentiated by the increased "emotionality" that rats living in a comfortable environment (i.e., EE) may experience when facing new, challenging events or environments. Blood alcohol levels, assessed at the end of a final drinking session occurring at the 12th hour of the dark phase, did not differ among the three rat groups and averaged approximately 150mg%, confirming that this experimental procedure may generate intoxicating levels of alcohol drinking in sP rats.

MiRNA-let-7i modulates status epilepticus via the TLR4 pathway

BackgroundStatus epilepticus (SE) is a neurological emergency associated with high mortality and morbidity. Many SE episodes cannot be quickly and effectively terminated with current medications. miRNA-Let-7i, a member of the miRNA-Let-7 family, has been found to be associated with a variety of brain pathophysiological and neurological diseases. However, its role in SE remains elusive and requires further clarification.MethodsThe expression of miRNA-Let-7i was detected in temporal lobe epilepsy (TLE) patients and SE model rats using the real-time quantitative polymerase chain reaction (RT-qPCR) method. Behavioral assays were performed in pilocarpine-induced SE model, and a whole-cell current clamp technique was employed to examine neuronal excitability. Neuronal apoptosis was evaluated by Nissl staining and terminal deoxynucleotidyl transferase-mediated dUTP end-labeling (TUNEL) assays.ResultsThe expression of miRNA-Let-7i was significantly reduced in the cortex and hippocampus of SE rats. The miRNA-Let-7i agomir and antagomir effectively regulated the levels of miRNA-Let-7i. In particular, the agomir significantly reduced the degree of SE and prolonged the latent period of SE, whereas the antagomir increased the degree of seizures and shortened the latent period. In addition, the agomir significantly decreased the frequency of action potentials, while the antagomir significantly increased it. Nissl staining and TUNEL assays demonstrated that the agomir increased the survival and decreased the apoptosis, while the antagomir had the opposite effects. In addition, a Toll-like receptor 4 (TLR4) inhibitor rescued the effects of antagomir on SE behavior and expression of IL-6 and TNF-α. Similar results on miRNA-Let-7i expression and effects of TLR4 inhibition were found in brain tissues of TLE patients.ConclusionsThe miRNA-Let-7i − TLR4 regulatory pathway is involved in SE, which provides insights into the pathogenesis of SE.

Long non-coding RNA H19 alleviates hippocampal damage in convulsive status epilepticus rats through the nuclear factor-kappaB signaling pathway

ABSTRACT Previous studies have demonstrated that inflammation plays a critical role in hippocampcal damage and cognitive dysfunction induced by convulsive status epilepticus (CSE). Emerging evidence indicated that the long non-coding RNA (lncRNA) H19 acts as an important regulator of inflammation in various diseases. However, the role of H19 in CSE is still unkonwn. In the present study, pilocarpine-induced SE rat model was used to explore the role of H19 in hippocampal neuron damage in CSE. Our results indicated that the increased level of H19 is positively correlated with the expression of inflammatory cytokines (TNF-α and IL-1β) in hippocampus of SE rats. Moreover, knockdown of H19 could inhibit the activation of microglia and suppress the expression of inflammatory cytokines via nuclear factor-kappaB (NF-κB) signaling pathway. It was further revealed that downregulation of H19 could alleviate hippocampal neuron damage induced by CSE. These findings indicated that H19 modulates inflammatory response and hippocampal damage through the NF-κB signaling pathway in the CSE rats, which provides a promising target to alleviate hippocampcal damage of CSE.

When Seizures Trigger "Extreme (Cardiac) Makeover".

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Modafinil exerts anticonvulsive effects against lithium-pilocarpine-induced status epilepticus in rats: A role for tumor necrosis factor-α and nitric oxide signaling

BackgroundStatus epilepticus (SE) is a continuous episode of seizures which leads to hippocampal neurodegeneration, severe systemic inflammation, and extreme damage to the brain. Modafinil, a psychostimulant and wake-promoting agent, has exerted neuroprotective and anti-inflammatory effects in previous preclinical studies. The aim of this study was to assess effects of modafinil on the lithium-pilocarpine-induced SE rat model and to explore possible involvement of tumor necrosis factor-α (TNF-α) and nitric oxide (NO) pathways in this regard. MethodsStatus epilepticus was provoked by injection of lithium chloride (127 mg/kg, intraperitoneally [i.p]) and pilocarpine (60 mg/kg, i.p.) in rats. Animals received different modafinil doses (50, 75, 100, and 150 mg/kg, i.p.) and SE scores were documented over 3 hours of duration. Moreover, the role of the nitrergic pathway in the effects of modafinil was evaluated by injection of the non-selective NO synthase (NOS) inhibitor L-NG-Nitro arginine methyl ester (L-NAME, 10 mg/kg, i.p.), the selective neuronal NOS inhibitor 7-nitroindazole (30 mg/kg, i.p.), and the selective inducible NOS inhibitor aminoguanidine (100 mg/kg, i.p.) 15 min before saline/vehicle or modafinil. The ELISA method was used to quantify TNF-α and NO metabolite levels in the isolated hippocampus. ResultsModafinil at 100 mg/kg significantly decreased SE scores (P < 0.01). Pre-treatment with L-NAME, 7-nitroindazole, and aminoguanidine significantly reversed the anticonvulsive effects of modafinil. Status epilepticus-induced animals showed significantly higher NO metabolite and TNF-α levels in their hippocampal tissues, an effect that was reversed by modafinil (100 mg/kg, i.p.) treatment. Administration of NOS inhibitors resulted in excessive NO level reduction but an escalation of TNF-α level in modafinil-treated SE-animals. ConclusionOur study revealed anticonvulsive effects of modafinil in the lithium-pilocarpine-induced SE rat model via possible involvement of TNF-α and nitrergic pathways.

Exposure to an enriched environment reduces alcohol self-administration in Sardinian alcohol-preferring rats

Living in an enriched environment (EE) produces a notable impact on several rodent behaviors, including those motivated by drugs of abuse. This picture is somewhat less clear when referring to alcohol-motivated behaviors. With the intent of contributing to this research field with data from one of the few rat lines selectively bred for excessive alcohol consumption, the present study investigated the effect of EE on operant oral alcohol self-administration in Sardinian alcohol-preferring (sP) rats. Starting from Postnatal Day (PND) 21, male sP rats were kept under 3 different housing conditions: impoverished environment (IE; single housing in shoebox-like cages with no environmental enrichment); standard environment (SE; small colony cages with 3 rats and no environmental enrichment); EE (large colony cages with 6 rats and multiple elements of environmental enrichment, including 2 floors, ladders, maze, running wheels, and shelter). From PND 60, rats were exposed to different phases of shaping and training of alcohol self-administration. IE, SE, and EE rats were then compared under (i) fixed ratio (FR) 4 (FR4) schedule of alcohol reinforcement for 20 daily sessions and (ii) progressive ratio (PR) schedule of alcohol reinforcement in a final single session. Acquisition of the lever-responding task (shaping) was slower in EE than IE and SE rats, as the likely consequence of a “devaluation” of the novel stimuli provided by the operant chamber in comparison to those to which EE rats were continuously exposed in their homecage or an alteration, induced by EE, of the rat “emotionality” state when facing the novel environment represented by the operant chamber. Training of alcohol self-administration was slower in EE than IE rats, with SE rats displaying intermediate values. A similar ranking order (IE>SE>EE) was also observed in number of lever-responses for alcohol, amount of self-administered alcohol, and breakpoint for alcohol under FR4 and PR schedules of reinforcement. These data suggest that living in a complex environment reduced the reinforcing and motivational properties of alcohol in sP rats. These results are interpreted in terms of the reinforcing and motivational properties of the main components of EE (i.e., social interactions, physical activities, exploration, novelty) substituting, at least partially, for those of alcohol.

Altered cardiac structure and function is related to seizure frequency in a rat model of chronic acquired temporal lobe epilepsy

ObjectiveThis study aimed to prospectively examine cardiac structure and function in the kainic acid-induced post-status epilepticus (post-KA SE) model of chronic acquired temporal lobe epilepsy (TLE), specifically to examine for changes between the pre-epileptic, early epileptogenesis and the chronic epilepsy stages. We also aimed to examine whether any changes related to the seizure frequency in individual animals. MethodsFour hours of SE was induced in 9 male Wistar rats at 10 weeks of age, with 8 saline treated matched control rats. Echocardiography was performed prior to the induction of SE, two- and 10-weeks post-SE. Two weeks of continuous video-EEG and simultaneous ECG recordings were acquired for two weeks from 11 weeks post-KA SE. The video-EEG recordings were analyzed blindly to quantify the number and severity of spontaneous seizures, and the ECG recordings analyzed for measures of heart rate variability (HRV). PicroSirius red histology was performed to assess cardiac fibrosis, and intracellular Ca2+ levels and cell contractility were measured by microfluorimetry. ResultsAll 9 post-KA SE rats were demonstrated to have spontaneous recurrent seizures on the two-week video-EEG recording acquired from 11 weeks SE (seizure frequency ranging from 0.3 to 10.6 seizures/day with the seizure durations from 11 to 62 s), and none of the 8 control rats. Left ventricular wall thickness was thinner, left ventricular internal dimension was shorter, and ejection fraction was significantly decreased in chronically epileptic rats, and was negatively correlated to seizure frequency in individual rats. Diastolic dysfunction was evident in chronically epileptic rats by a decrease in mitral valve deceleration time and an increase in E/E` ratio. Measures of HRV were reduced in the chronically epileptic rats, indicating abnormalities of cardiac autonomic function. Cardiac fibrosis was significantly increased in epileptic rats, positively correlated to seizure frequency, and negatively correlated to ejection fraction. The cardiac fibrosis was not a consequence of direct effect of KA toxicity, as it was not seen in the 6/10 rats from separate cohort that received similar doses of KA but did not go into SE. Cardiomyocyte length, width, volume, and rate of cell lengthening and shortening were significantly reduced in epileptic rats. SignificanceThe results from this study demonstrate that chronic epilepsy in the post-KA SE rat model of TLE is associated with a progressive deterioration in cardiac structure and function, with a restrictive cardiomyopathy associated with myocardial fibrosis. Positive correlations between seizure frequency and the severity of the cardiac changes were identified. These results provide new insights into the pathophysiology of cardiac disease in chronic epilepsy, and may have relevance for the heterogeneous mechanisms that place these people at risk of sudden unexplained death.

Environment-dependent behavioral traits and experiential factors shape addiction vulnerability.

The transition from controlled drug use to drug addiction depends on an interaction between a vulnerable individual, their environment and a drug. Here we tested the hypothesis that conditions under which individuals live influence behavioral vulnerability traits and experiential factors operating in the drug taking environment to determine the vulnerability to addiction. The role of behavioral vulnerability traits in mediating the influence of housing conditions on the tendency to acquire cocaine self-administration was characterized in 48 rats housed in either an enriched (EE) or a standard (SE) environment. Then, the influence of these housing conditions on the individual vulnerability to develop addiction-like behavior for cocaine or alcohol was measured in 72 EE or SE rats after several months of cocaine self-administration or intermittent alcohol drinking, respectively. The determining role of negative experiential factors in the drug taking context was further investigated in 48 SE rats that acquired alcohol drinking to self-medicate distress in a schedule-induced polydipsia procedure. The environment influenced the acquisition of drug intake through its effect on behavioral markers of resilience to addiction. In contrast, the initiation of drug taking as a coping strategy or in a negative state occasioned by the contrast between enriched housing conditions and a relatively impoverished drug taking setting, facilitated the development of compulsive cocaine and alcohol intake. These data indicate that addiction vulnerability depends on environmentally determined experiential factors, and suggest that initiating drug use through negative reinforcement-based self-medication facilitates the development of addiction in vulnerable individuals. SIGNIFICANCE STATEMENT: The factors that underlie an individual's vulnerability to switch from controlled, recreational drug use to addiction are not well understood. We showed that in individuals housed in enriched conditions, the experience of drugs in the relative social and sensory impoverishment of the drug taking context, and the associated change in behavioral traits of resilience to addiction, exacerbate the vulnerability to develop compulsive drug intake. We further demonstrated that the acquisition of alcohol drinking as a mechanism to cope with distress increases the vulnerability to develop compulsive alcohol intake. Together these results demonstrate that experiential factors in the drug taking context shape the vulnerability to addiction.

Dietary supplementation with manganese and selenium offer protection against cadmium-induced oxidative damage to rat liver and kidney

The present study determined the effect of pre-supplementation with manganese (Mn) and selenium (Se) on biomarkers of oxidative stress in the liver and kidneys of rats exposed to a mild dose of cadmium. Sixteen Male Wistar strain rats (180-200 g b. wt) were divided into four groups (control, Cd alone, Mn + Se + Cd and Mn + Se). The rats used as the control received a normal rat diet and tap water throughout the study while the Cd alone rats received a normal rat diet and then exposed to a single daily oral dose of cadmium (3 mg CdCl2/kg) in drinking water for three days. Mn + Se + Cd rats were pretreated with Mn (3 mg MnCl2/kg/day) and Se (3mg SeO2/kg/day) for seven days and thereafter received a single daily oral dose of cadmium (3 mg CdCl2/kg) in drinking water for three days while Mn + Se rats were exposed to only Mn (3 mg MnCl2/kg/day) and Se (3mg SeO2/kg/day) for seven days. At the end of the experiment tissue cadmium concentration, membrane lipid peroxidation, glutathione content, and activities of antioxidant enzymes catalase, superoxide dismutase, and glutathione peroxidase were determined in the liver and kidney samples. The results showed that pretreatment with Mn and Se effectively countered Cd-induced cadmium accumulation, membrane lipid peroxidation, depletion of the non-enzymic antioxidant, glutathione, and induction of the antioxidant enzymes catalase, superoxide dismutase and glutathione peroxidase in the liver and kidney. It can be concluded that pre-supplementation with Mn and Se significantly reversed Cd-induced deleterious alterations in the liver and kidney tissue of the rats.

Dynamic Change of Shanks Gene mRNA Expression and DNA Methylation in Epileptic Rat Model and Human Patients.

Synaptic protein shanks (SH3 and multiple ankyrin repeat domains protein, Shank) have emerged as an important mediator of synaptic remodeling. Synaptic remodeling is a common pathogenic process in various neurological disorders including epilepsy. However, the expression and function of shanks gene in epileptogenesis has not been investigated to date. Herein, we investigated the expression of shanks (shank1/2/3) mRNA expression in both epileptic rats and epilepsy patients. Furthermore, methyl target sequencing was applied to explore the relationship between shank mRNA expression and DNA methylation in both rats and human patients. In general rat model, shank1/2/3 mRNA was downregulated at acute stage, upregulated at latent stage, and returned to the basal level at chronic stage. Ten CpG sites of shank1 was found differentially methylated, out of which 6 were hypermethylated. Seventeen CpG sites of shank3 were differentially methylated, out of which 8 were hypermethylated. In human epilepsy patients, decreased shank2 mRNA was detected from the brain tissue, with DNA hypermethylation dominant from both brain (18 out of 30) and blood tissue (58 out of 80), indicating the regulation role of DNA methylation on shank2 expression. In conclusion, our finding suggests the participation of the shanks gene in the pathophysiology of seizure, out of which 2 shank3 CpG sites (Chr7: 130473419, and Chr7: 130473405) may play an important role in shank3 expression at both the acute and latent stages in the SE rat model.

Endocannabinoid modulating drugs improve anxiety but not the expression of conditioned fear in a rodent model of post-traumatic stress disorder

The endocannabinoid (eCB) system is a potential target for the treatment of symptoms of post-traumatic stress disorder (PTSD). Similar to clinical PTSD, approximately 25–30% of rats that undergo cued fear conditioning exhibit impaired extinction learning. In addition to extinction-resistant fear, these “weak extinction” (WE) rats show persistent anxiety-like behaviors. The goal of the present study was to test the hypothesis that behavioural differences between WE animals and those presenting normal extinction patterns (strong extinction; SE) could be mediated by the eCB system. Rats undergoing fear conditioning/extinction and fear recall sessions were initially segregated in weak and strong-extinction groups. Two weeks later, animals underwent a fear recall session followed by a novelty-suppressed feeding (NSF) test. In acute experiments, WE rats were injected with either the fatty acid amide hydrolase (FAAH) inhibitor URB597 or the CB1 agonist WIN55,212-2 1 h prior to long-term recall and NSF testing. SE animals were injected with the inverse CB1 receptor agonist AM251. In chronic experiments, WE and SE rats were given daily injections of URB597 or AM251 between short and long-term recall sessions. We found that acute administration of WIN55,212-2 but not URB597 reduced anxiety-like behaviour in WE rats. In contrast, AM251 was anxiogenic in SE animals. Neither treatment was effective in altering freezing expression during fear recall. The chronic administration of AM251 to SE or URB597 to WE did not alter fear or anxiety-like behaviour or changed the expression of FAAH and CB1. Together, these results suggest that systemic manipulations of the eCB system may alter anxiety-like behaviour but not the behavioural expression of an extinction-resistant associative fear memory.

Bone Health in Rats With Temporal Lobe Epilepsy in the Absence of Anti-Epileptic Drugs.

Rationale: Epilepsy patients often exhibit reduced bone mineral density and are at an increased risk of bone fracture. Whether these bone abnormalities are due to the use of anti-epileptic drugs (AED’s) or the disease itself is unknown. For example, although decreased bone health in epilepsy patients is generally attributed to the use of AED’s, seizures can also trigger a number of physiological processes that have the potential to affect bone. Therefore, to assess whether bone abnormalities occur in epilepsy in the absence of AED’s, the current study investigated mechanical characteristics and trabecular bone morphology in rats with chronic temporal lobe epilepsy. Methods: Ten-week old male Wistar rats underwent kainic acid-induced status epilepticus (SE; n = 7) or a sham procedure (n = 9). Rats were implanted with EEG recording electrodes at nine weeks post-SE, and video-EEG was continuously recorded for one week at 10- and 22-weeks post-SE to confirm that SE rats had spontaneous seizures. Open-field testing to assess locomotion was conducted at 23-weeks post-SE. At 24-weeks post-SE, rats were euthanized and tibia were extracted to determine trabecular morphology by micro-computed tomography (µCT), while femurs were used to investigate mechanical properties via 3-point bending. Results: All post-SE rats had spontaneous seizures at 10- and 22-weeks post-SE, while none of the sham rats had seizures. µCT trabecular analysis of tibia revealed no differences in total volume, bone volume, bone volume fraction, trabecular number, or trabecular separation between post-SE or sham rats, although post-SE rats did have increased trabecular thickness. There were also no group differences in total distance travelled in the open field suggesting that activity levels did not account for the increased trabecular thickness. In addition, no differences in mechanical properties of femurs were observed between the two groups. Conclusion: There was a lack of overt bone abnormalities in rats with chronic temporal lobe epilepsy in the absence of AED treatment. Although further studies are still needed, these findings may have important implications towards understanding the source (e.g., AED treatments) of bone abnormalities in epilepsy patients.

Early treatment with C1 esterase inhibitor improves weight but not memory deficits in a rat model of status epilepticus

BackgroundStatus epilepticus (SE) is a prolonged and continuous seizure that lasts for at least 5 min. An episode of SE in a healthy system can lead to the development of spontaneous seizures and cognitive deficits which may be accompanied by hippocampal injury and microgliosis. Although the direct mechanisms underlying the SE-induced pathophysiology remain unknown, a candidate mechanism is hyperactivation of the classical complement pathway (C1q-C3 signaling). We recently reported that SE triggered an increase in C1q-C3 signaling in the hippocampus that closely paralleled cognitive decline. Thus, we hypothesized that blocking activation of the classical complement pathway immediately after SE may prevent the development of SE-induced hippocampal-dependent learning and memory deficits. MethodsBecause C1 esterase inhibitor (C1-INH) negatively regulates activation of the classical complement pathway, we used this drug to test our hypothesis. Two groups of male rats were subjected to 1 hr of SE with pilocarpine (280–300 mg/kg, i.p.), and treated with either C1-INH (SE+C1-INH, 20 U/kg, s.c.) or vehicle (SE+veh) at 4, 24, and 48 h after SE. Control rats were treated with saline. Body weight was recorded for up to 23 days after SE. At two weeks post SE, recognition and spatial memory were determined using Novel Object Recognition (NOR) and Barnes maze (BM), respectively, as well as locomotion and anxiety-like behaviors using Open Field (OF). Histological and biochemical methods were used to measure hippocampal injury including cell death, microgliosis, and inflammation. ResultsOne day after SE, both SE groups had a significant loss of body weight compared to controls (p<0.05). By day 14, the weight of SE+C1-INH rats was significantly higher than SE+veh rats (p<0.05), and was not different from controls (p>0.05). At 14 days post-SE, SE+C1-INH rats displayed higher mobility (distance travelled and average speed, p<0.05) and had reduced anxiety-like behaviors (outer duration, p<0.05) than control or SE+veh rats. In NOR, control rats spent significantly more time exploring the novel object vs. the familiar (p<0.05), while rats in both SE groups spent similar amount of time exploring both objects. During days 1–4 of BM training, the escape latency of the control group significantly decreased over time (p<0.05), whereas that of the SE groups did not improve (p>0.05). Compared to vehicle-treated SE rats, SE+C1-INH rats had increased levels of C3 and microglia in the hippocampus, but lower levels of caspase-3 and synaptic markers. ConclusionsThese findings suggest that acute treatment with C1-INH after SE may have some protective, albeit limited, effects on the physiological recovery of rats’ weight and some anxiolytic effects, but does not attenuate SE-induced deficits in hippocampal-dependent learning and memory. Reduced levels of caspase-3 suggest that treatment with C1-INH may protect against cell death, perhaps by regulating inflammatory pathways and promoting phagocytic/clearance pathways.

The Expression Alteration of BC1 RNA and its Interaction with Eukaryotic Translation Initiation Factor eIF4A Post-Status Epilepticus

Abnormal dendritic sprouting and synaptic remodelling are important pathological features of temporal lobe epilepsy. BC1 RNA is a translation repressor involved in the regulation of the dendritic protein synthesis and mRNA transport, which is essential for dendritic development and plasticity. The expression alteration of BC1 RNA in the pilocarpine induced epilepsy model remains unknown. It is unclear if the interactions between BC1 RNA and eukaryotic initiation factor 4A (eIF4A) exists in this model. The purpose of this study was to investigate the expression changes of BC1 RNA and its interactions with eIF4A post-status epilepticus (SE). Chloride lithium and pilocarpine were used to induce the SE rat model. Either a whole brain or hippocampus tissues were collected at different time points after SE. The expression patterns of BC1 was detected by qPCR and in situ hybridization. The levels of eIF4AI/II protein expression were analyzed via western blotting and immunohistochemistry. The BC1 RNA-eIF4AI/II interaction was determined by electrophoretic mobility shift assay (EMSA). We found that the BC1 RNA levels decreased in hippocampus 3d, 1w and 2w post-SE before the levels recovered. The eIF4AI/II began to rise 3d post-SE and reached the maximum level 1w post-SE. After 1w post-SE the levels decreased in the hippocampal CA1, CA3 and DG subregions. EMSA analysis showed that BC1 RNA specifically interacted with the eIF4AI/II. The BC1 RNA-eIF4AI/II complex reduced to the lowest level 1w post-SE. Our results suggested that BC1 has a negative regulatory correlation with eIF4AI/II, where BC1 RNA could be involved in epileptogenesis by regulating dendritic protein synthesis.

Neonatal tobacco smoke reduces thermogenesis capacity in brown adipose tissue in adult rats.

Maternal smoking is a risk factor for progeny obesity. We have previously shown, in a rat model of neonatal tobacco smoke exposure, a mild increase in food intake and a considerable increase in visceral adiposity in the adult offspring. Males also had secondary hyperthyroidism, while females had only higher T4. Since brown adipose tissue (BAT) hypofunction is related to obesity, here we tested the hypothesis that higher levels of thyroid hormones are not functional in BAT, suggesting a lower metabolic rate. We evaluated autonomic nerve activity in BAT and its function in adult rats that were exposed to tobacco smoke during lactation. At birth, litters were adjusted to 3 male and 3 female pups/litter. From postnatal day (PND) 3 to 21, Wistar lactating rats and their pups were divided into SE group, smoke-exposed in a cigarette smoking machine (4 times/day) and C group, exposed to filtered air. Offspring were sacrificed at PND180. Adult SE rats of both genders had lower interscapular BAT autonomic nervous system activity, with higher BAT mass but no change in morphology. BAT UCP1 and CPT1a protein levels were decreased in the SE groups of both genders. Male SE rats had lower β3-AR, TRα1, and TRβ1 expression while females showed lower PGC1α expression. BAT Dio2 mRNA and hypothalamic POMC and MC4R levels were similar between groups. Hypothalamic pAMPK level was higher in SE males and lower in SE females. Thus, neonatal cigarette smoke exposure induces lower BAT thermogenic capacity, which can be obesogenic at adulthood.

Intracerebroventricular injection of miR-146a relieves seizures in an immature rat model of lithium-pilocarpine induced status epilepticus

ObjectiveStatus epilepticus (SE) is a common, life-threatening neurological emergency that confers a high degree of morbidity and mortality. Increasing evidence indicates that neuroinflammation plays a critical role in the pathogenesis of SE. MicroRNA-146a (miR-146a) has been reported to be an important posttranscriptional inflammation-associated microRNA. The aim of this study was to investigate the effect of miR-146a in SE and the mechanism by which it operates. MethodsTo study the effect of miR-146a in SE, we chose intracerebroventricular injection for rat at 21–28days old, and made a lithium-pilocarpine-induced SE rat model. We assessed latency time and Lado grade by behavior observation. We performed qPCR, ELISA and western blot tests on rat hippocampus to measure the expression levels of miR-146a, IL-1β, TNF-α, TLR4 and NF-κB. ResultsIn the miR-146a antagomir injection group, the latency to generalized convulsions was shorter, the duration and degree of seizures were more severe, the expression level of miR-146a was clearly decreased, and IL-1β, TNF-α, TLR4 and NF-κB were all significantly up-regulated. The opposite was true for rats treated with miR-146a agomir. ConclusionOur findings elucidate the role of inflammation in the pathogenesis of SE in immature rats, and show that regulating the expression level of miR-146a may provide a novel insights into the pathogenesis of SE.

Prefrontal Cortex Deep Brain Stimulation Improves Fear and Anxiety-Like Behavior and Reduces Basolateral Amygdala Activity in a Preclinical Model of Posttraumatic Stress Disorder.

Deep brain stimulation (DBS) is being investigated for a number of psychiatric indications, including posttraumatic stress disorder (PTSD). Preclinical studies continue to be a cornerstone for the development of new DBS applications. We investigate whether DBS delivered to the infralimbic cortex (IL), a region involved in mechanisms of stress resiliency, may counter behavioral abnormalities in rats that present persistent extinction deficits and long-term anxiety after exposure to fear conditioning. Rats undergoing fear conditioning/extinction were segregated into weak and strong extinction groups (WE >70% or SE <30% of freezing during extinction). Following 2 weeks of DBS, animals were exposed to novel recall sessions and tested in the open field, novelty-suppressed feeding, and elevated plus maze. zif268 expression was measured in structures involved in mechanisms of fear and stress. In vivo electrophysiology was used to record activity from the basolateral amygdala (BLA). We found that DBS improved extinction deficits and anxiety-like behavior in WE animals, having no significant effects in SE rats. No major differences in absolute zif268 levels were recorded across groups. However, correlation between zif268 expression in the IL and BLA was disrupted in WE animals, a deficit that was countered by DBS treatment. Electrophysiology experiments have shown that DBS reduced BLA firing of both putative principal cells and interneurons in WE rats, with no significant differences being detected between SE and SE DBS animals. In summary, IL DBS mitigated fear, partially improved anxiety-like behavior, reversed neurocircuitry abnormalities, and reduced BLA cell firing in a preclinical model of PTSD.