Protective Effects of Anthocleista djalonensis Extracts against Pentylenetetrazole-Induced Epileptic Seizures and Neuronal Cell Loss: Role of Antioxidant Defense System

Neuroprotective role of chlorogenic acid against hippocampal neuroinflammation, oxidative stress, and apoptosis following acute seizures induced by pentylenetetrazole

This study investigated the neuroprotective effect of chlorogenic acid (CGA) on pentylenetetrazole (PTZ)-induced acute epileptic seizures in mice. Epileptic animals received CGA (200 mg/kg) or sodium valproate (standard antiepileptic agent, 200 mg/kg) for four weeks. Results revealed that pre-administration of CGA significantly reversed the behavioral changes following pentylenetetrazole (PTZ) injection. Further, CGA pre-treatment caused significant increases in acetylcholinesterase (AChE) activity and brain-derived neurotrophic factor (BDNF) levels, along with marked increases in dopamine, norepinephrine, and serotonin levels. Additionally, the increased antioxidant enzymes activities, along with higher glutathione (GSH) contents and upregulated nuclear factor erythroid 2-related factor 2 (Nrf2) gene expression, were indicative of a notable improvement in the cellular antioxidant defense in mice treated with CGA. These results were associated with lowered malondialdehyde (MDA) and nitric oxide (NO) levels. Moreover, epileptic mice that received CGA showed significant declines in the content of interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor alpha (TNF-α), and nuclear factor kappa-B (NF-κB), besides downregulating inducible nitric oxide synthase (iNOS) expression. Remarkably, CGA counteracted hippocampal apoptosis by lessening the levels of pro-apoptotic biomarkers [Bcl-2-associated X protein (Bax) and caspase-3] and increasing the anti-apoptogenic marker level of B-cell lymphoma 2 (Bcl-2). The hippocampal histopathological findings corroborated the abovementioned changes. In sum, these findings suggest that CGA could mediate the neuroprotective effect against PTZ-induced epilepsy via modulation of neurotransmitters, oxidative damage, neuroinflammation, and apoptosis. CGA, therefore, could be considered a valuable antiepileptic therapeutic supplement.

Antioxidant Therapy Reduces Oxidative Stress, Restores Na,K-ATPase Function and Induces Neuroprotection in Rodent Models of Seizure and Epilepsy: A Systematic Review and Meta-Analysis

Epilepsy is a neurological disorder characterized by epileptic seizures resulting from neuronal hyperexcitability, which may be related to failures in Na,K-ATPase activity and oxidative stress participation. We conducted this study to investigate the impact of antioxidant therapy on oxidative stress, Na,K-ATPase activity, seizure factors, and mortality in rodent seizure/epilepsy models induced by pentylenetetrazol (PTZ), pilocarpine (PILO), and kainic acid (KA). After screening 561 records in the MEDLINE, EMBASE, Web of Science, Science Direct, and Scopus databases, 22 were included in the systematic review following the PRISMA guidelines. The meta-analysis included 14 studies and showed that in epileptic animals there was an increase in the oxidizing agents nitric oxide (NO) and malondialdehyde (MDA), with a reduction in endogenous antioxidants reduced glutathione (GSH) and superoxide dismutase (SO). The Na,K-ATPase activity was reduced in all areas evaluated. Antioxidant therapy reversed all of these parameters altered by seizure or epilepsy induction. In addition, there was a percentage decrease in the number of seizures and mortality, and a meta-analysis showed a longer seizure latency in animals using antioxidant therapy. Thus, this study suggests that the use of antioxidants promotes neuroprotective effects and mitigates the effects of epilepsy. The protocol was registered in the Prospective Register of Systematic Reviews (PROSPERO) CRD42022356960.

The Effect of Adenosine Signaling on Memory Impairment Induced by Pentylenetetrazole in Zebrafish

Epilepsy is characterized by the manifestation of spontaneous and recurrent seizures. The high prevalence of comorbidities associated with epilepsy, such as cognitive dysfunction, affects the patients quality of life. Adenosine signaling modulation might be an effective alternative to control seizures and epilepsy-associated comorbidities. This study aimed to verify the role of adenosine modulation on the seizure development and cognitive impairment induced by pentylenetetrazole (PTZ) in zebrafish. At first, animals were submitted to a training session in the inhibitory avoidance test and, after 10 min, they received an intraperitoneal injection of valproate, adenosine A₁ receptor agonist cyclopentyladenosine (CPA), adenosine A₁ receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine (DPCPX), adenosine A_2A receptor antagonist ZM 241385, adenosine deaminase inhibitor erythro-9-(2-hydroxy-3-nony1)-adenine hydrochloride (EHNA) or the nucleoside transporter inhibitor dipyridamole. Thirty min after the intraperitoneal injection, the animals were exposed to 7.5 mM PTZ for 10 min, where they were evaluated for latency to reach the seizure stages (I, II, and III). Finally, 24 h after the training session, the animals were submitted to the inhibitory avoidance test to verify their cognitive performance during the test session. Valproate, CPA, and EHNA showed antiseizure effects and prevented the memory impairment induced by PTZ exposure. DPCPX, ZM 241385, and dipyridamole pretreatments caused no changes in seizure development; however, these drugs prevented memory impairment without altering locomotion. Our results reinforce the antiseizure effects of adenosine signaling and support the idea that the involvement of adenosine in memory processes may be a target for preventive strategies against cognitive impairment associated with epilepsy.

Monosodium glutamate induces cortical oxidative, apoptotic, and inflammatory challenges in rats: the potential neuroprotective role of apigenin

Monosodium glutamate (MSG) is used as a flavor, and a taste enhancer was reported to evoke marked neuronal impairments. This study investigated the neuroprotective ability of flavonoid apigenin against neural damage in MSG-administered rats. Adult male rats were allocated into four groups: control, apigenin (20 mg/kg b.wt, orally), MSG (4 g/kg b.wt, orally), and apigenin + MSG at the aforementioned doses for 30 days. Regarding the levels of neurotransmitters, our results revealed that apigenin augmented the activity of acetylcholinesterase (AChE) markedly, and levels of brain monoamines (dopamine, norepinephrine, and serotonin) accompanied by lessening the activity of monoamine oxidase (MAO) as compared to MSG treatment. Moreover, apigenin counteracted the MSG-mediated oxidative stress by decreasing the malondialdehyde (MDA) levels together with elevating the glutathione (GSH) levels. In addition, pretreatment with apigenin induced notable increases in the activities of cortical superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione reductase (GR). Furthermore, apigenin attenuated the cortical inflammatory stress as indicated by lower levels of pro-inflammatory mediators such as interleukin-1 b (IL-1b), tumor necrosis factor-α (TNF-α), and nitric oxide (NO) as well as downregulated inducible nitric oxide synthase (iNOS) expression levels. Histopathological screening validated the abovementioned results and revealed that apigenin restored the distorted cytoarchitecture of the brain cortex. Thus, the present findings collectively suggest that apigenin exerted significant protection against MSG-induced neurotoxicity by enhancing the cellular antioxidant response and attenuating inflammatory machineries in the rat brain cortex.