Proanthocyanidins alleviate pentylenetetrazole-induced epileptic seizures in mice via the antioxidant activity

Diet-derived circulating antioxidants and risk of epilepsy: a Mendelian randomization study

Background

Previous studies suggest a link between diet-derived circulating antioxidants and epilepsy, but the causal relationship is unclear. This study aims to investigate the causal effect of these antioxidants on epilepsy.

Methods

To assess the causal link between dietary antioxidants and epilepsy risk, we conducted a two-sample Mendelian randomization (MR) analysis. This involved examining antioxidants such as zinc, selenium, α- and γ-tocopherol, vitamin A (retinol), vitamin C (ascorbate), and vitamin E (α-tocopherol). We utilized instrumental variables (IVs) which were genetic variations highly associated with these commonly used antioxidants. Exposure data were sourced from a comprehensive genome-wide association study (GWAS). We aggregated data from the International League Against Epilepsy (ILAE) Consortium sample, which included various types of epilepsy, as an outcome variable. Finally, we applied the inverse variance weighting method and conducted sensitivity analyses for further validation.

Results

Based on the primary MR estimates and subsequent sensitivity analyses, the inverse variance weighting (IVW) method revealed that a genetically predicted increase in zinc per standard deviation was positively associated with three types of epilepsy. This includes all types of epilepsy (OR = 1.06, 95% CI: 1.02-1.11, p = 0.008), generalized epilepsy (OR = 1.13, 95% CI: 1.01-1.25, p = 0.030), and focal epilepsy (documented hippocampal sclerosis) (OR = 1.01, 95% CI: 1.00-1.02, p = 0.025). However, there is no evidence indicating that other antioxidants obtained from the diet affect the increase of epilepsy either positively or negatively.

Conclusion

Our research indicates that the risk of developing epilepsy may be directly linked to the genetic prediction of zinc, whereas no such association was found for other antioxidants.

(-)-α-bisabolol exerts neuroprotective effects against pentylenetetrazole-induced seizures in rats by targeting inflammation and oxidative stress

Epilepsy is the most common neurological disorder which is accompanied with behavioral and psychiatric alternations. Current evidences have shown that (-)-α-bisabolol (BSB) possess anti-inflammatory and antioxidative effects in several animal studies. Here, we conducted present study to evaluate its neuroprotective effects against pentylenetetrazole (PTZ)-induced seizures in rats. We used fifty male rats and they were randomly assigned into 5 groups control, BSB100, PTZ, BSB50 + PTZ, BSB100 + PTZ. The animals intraperitoneally received PTZ (45 mg/kg) for ten consecutive days to induce epilepsy model. BSB in doses of 50 and 100 mg/kg was administrated orally one hour before PTZ administration for ten days. The elevated plus maze (EPM) test was carried out to assess anxiety-like behavior. The seizure intensity was evaluated according to modifies Racine's convulsion scale (RCS). Y-maze and passive avoidance were utilized to assess working memory and aversive memory. The expression of pro-inflammatory cytokines and oxidative stress factors were measured using the enzyme-linked immunosorbent assay (ELISA). The neuronal cell loss in the hilar region was assessed using Nissl staining. Results showed that PTZ-treated rats had more seizure intensity, anxiety-like behavior, memory deficits, higher levels of TNF-α, IL-1β, and oxidative markers. Pre-treatment with BSB 100 significantly inhibited seizure intensity, anxiety-like behavior, and memory deficits; reduced levels of TNF-α, IL-1β, and MDA oxidative markers. Collectively, outcome of this work shows that BSB at the dose of 100 mg/kg may exert neuroprotective effects by mitigating seizures, oxidative stress, and neuroinflammation, and ameliorates memory and anxiety disorders in the PTZ-induced seizure rats.

Therapeutic Strategies to Ameliorate Neuronal Damage in Epilepsy by Regulating Oxidative Stress, Mitochondrial Dysfunction, and Neuroinflammation

Epilepsy is a central nervous system disorder involving spontaneous and recurring seizures that affects 50 million individuals globally. Because approximately one-third of patients with epilepsy do not respond to drug therapy, the development of new therapeutic strategies against epilepsy could be beneficial. Oxidative stress and mitochondrial dysfunction are frequently observed in epilepsy. Additionally, neuroinflammation is increasingly understood to contribute to the pathogenesis of epilepsy. Mitochondrial dysfunction is also recognized for its contributions to neuronal excitability and apoptosis, which can lead to neuronal loss in epilepsy. This review focuses on the roles of oxidative damage, mitochondrial dysfunction, NAPDH oxidase, the blood-brain barrier, excitotoxicity, and neuroinflammation in the development of epilepsy. We also review the therapies used to treat epilepsy and prevent seizures, including anti-seizure medications, anti-epileptic drugs, anti-inflammatory therapies, and antioxidant therapies. In addition, we review the use of neuromodulation and surgery in the treatment of epilepsy. Finally, we present the role of dietary and nutritional strategies in the management of epilepsy, including the ketogenic diet and the intake of vitamins, polyphenols, and flavonoids. By reviewing available interventions and research on the pathophysiology of epilepsy, this review points to areas of further development for therapies that can manage epilepsy.

Possible Interaction of Opioidergic and Nitrergic Pathways in the Anticonvulsant Effect of Ivermectin on Pentylenetetrazole-Induced Clonic Seizures in Mice

Ivermectin (IVM) is an antiparasitic drug that primarily works by the activation of GABA_A receptors. The potential pharmacological pathways behind the anti-convulsant effect of IVM haven't yet been identified. In this study, intravenous injection of pentylenetetrazole (PTZ)-induced clonic seizure in mice was investigated in order to assess the possible influence of IVM on clonic seizure threshold (CST). We also look at the function of the Opioidergic and nitrergic pathways in IVM anticonvulsant action on clonic seizure threshold. IVM (0.5, 1, 5, and 10 mg/kg, i.p.) raised the PTZ-induced CST, according to our findings. Furthermore, the ineffective dose of nitric oxide synthase inhibitors (L-NAME 10 mg/kg, i.p.), and (7-NI 30 mg/kg, i.p.) or opioidergic system agonist (morphine 0.25 mg/kg, i.p.) were able to amplify the anticonvulsive action of IVM (0.2 mg/kg, i.p.). Moreover, the anticonvulsant effect of IVM was reversed by an opioid receptor antagonist (naltrexone 1 mg/kg, i.p.). Furthermore, the combination of the ineffective dose of morphine as an opioid receptor agonist with either L-NAME (2 mg/kg, i.p.) or 7-NI (10 mg/kg, i.p.) and with an ineffective dose of IVM (0.2 mg/kg, i.p.) had a significant anticonvulsant effect. Taken together, IVM has anticonvulsant activity against PTZ-induced clonic seizures in mice, which may be mediated at least in part through the interaction of the opioidergic system and the nitric oxide pathway.

Antibiotics modulate frequency and early generation of epileptic seizures in zebrafish

Antibiotics have been used for decades to treat various bacterial infections. Apart from bactericidal activities, their potential side effects have not been much studied or evaluated. Neurotoxicity is a major concern in the case of β-lactam and fluoroquinolone families, which can result in convulsions or seizures. Here, we proposed a hypothesis to check whether antibiotic treatment can conclusively enhance anxiety-like behaviours and how seizure behavioural profile gets modulated in pentylenetetrazole (PTZ)-treated zebrafish. Zebrafish were treated with selected antibiotics such as 25 mg/L Penicillin G (PG) and Ciprofloxacin (CPFX), for 7 days and thereafter exposed to PTZ (7.5 mM) for 20 min. The data indicate that PG and CPFX-treated groups exhibited anxiety-like or stressed behavioural phenotypes in the novel tank test (6 min), and also, they were found to promote hyperactivity. Early onset of PTZ-induced seizure-like behavioural scores, the heightened intensity of seizure and reduced latency in different scores were found in PG and CPFX-administered groups. This study substantiates that PG and CPFX as potential seizure modulators in zebrafish. The zebrafish is a well-established and still expanding model organism in many fields. Here, we again reinforce zebrafish as a prominent model to investigate seizure-like neuro-behavioural entities and confirm that chronic antibiotic use has negative consequences that can exacerbate the circumstances of vertebrate species exhibiting seizure-related reactions.

The Neuroprotective Effect Associated with Echinops spinosus in an Acute Seizure Model Induced by Pentylenetetrazole

Echinops spinosus (ES) is a medicinal plant with a wide range of pharmacological and biological effects. It is a medicinal herb having a variety of therapeutic characteristics, including antioxidant, anti-inflammatory, and antibacterial capabilities. The primary goal of this research is to investigate the neuroprotective and anticonvulsant characteristics of E. spinosa extract (ESE) against pentylenetetrazole (PTZ)-induced acute seizures. Negative control rats, ESE treatment rats, PTZ acute seizure model rats, ESE + PTZ rats, and Diazepam + PTZ rats were used in the study. The rats were given a 7-day treatment. ESE pretreatment elevated the latency to seizure onset and lowered seizure duration after PTZ injection. By reducing Bax levels and enhancing antiapoptotic Bcl-2 production, ESE prevented the release of interleukin-1β, tumor necrosis factor-α, and cyclooxygenase-2, as well as preventing hippocampal cell death after PTZ injection. ESE corrected the PTZ-induced imbalance in gamma-aminobutyric acid levels and increased the enzyme activity of Na⁺/K⁺-ATPase. Echinops spinosus is a potent neuromodulatory, antioxidant, antiinflammatory, and antiapoptotic plant that could be employed as a natural anticonvulsant in the future.