Neuroprotective Effect of Fisetin Through Suppression of IL-1R/TLR Axis and Apoptosis in Pentylenetetrazole-Induced Kindling in Mice

Abstract

Epilepsy is a complex neurological disorder, characterized by frequent electrical activity in brain regions. Inflammation and apoptosis cascade activation are serious neurological sequelae during seizures. Fisetin (3, 3′,4′,7-tetrahydroxyflavone), a flavonoid molecule, is considered for its effective anti-inflammatory and anti-apoptotic properties. This study investigated the neuroprotective effect of fisetin on experimental epilepsy. For acute studies, increasing current electroshock (ICES) and pentylenetetrazole (PTZ)-induced seizure tests were performed to evaluate the antiseizure activity of fisetin. For the chronic study, the kindling model was established by the administration of PTZ in subconvulsive dose (25 mg/kg, i.p.). Mice were treated with fisetin (5, 10, and 20 mg/kg, p.o.) to study its probable antiseizure mechanism. The kindled mice were evaluated for seizure scores. Their hippocampus and cortex were assessed for neuronal damage, inflammation, and apoptosis. Histological alterations were observed in the hippocampus of the experimental mice. Levels of high mobility group box 1 (HMGB1), Toll-like receptor-4 (TLR-4), interleukin-1 receptor 1 (IL-1R1), interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) were assessed in the hippocampus and cortex by ELISA. The immunoreactivity and mRNA expressions of nuclear factor-κB (NF-κB), cyclooxygenase-2 (COX-2), cytochrome C, and caspase-3 were quantified by immunohistochemical analysis and real-time PCR. Phosphorylation ELISA was performed to evaluate AkT/mTOR (mammalian target of rapamycin) activation in the hippocampus and cortex of the kindled mice. The results showed that fisetin administration increased the seizure threshold current (STC) in the ICES test. In PTZ-induced seizures, fisetin administration increased the latency for myoclonic jerks (MJs) and generalized seizures (GSs). In the PTZ-induced kindling model, fisetin administration dose-dependently suppressed the development of kindling and the associated neuronal damage in the experimental mice. Further, fisetin administration ameliorated kindling-induced neuroinflammation as evident from decreased levels of HMGB1, TLR-4, IL-1R1, IL-1β, IL-6, and TNF-α in the hippocampus and cortex of the kindled mice. Also, the immunoreactivity and mRNA expressions of inflammatory molecules, NF-κB, and COX-2 were decreased with fisetin administration in the kindled animals. Decreased phosphorylation of the AkT/mTOR pathway was reported with fisetin administration in the hippocampus and cortex of the kindled mice. The immunoreactivity and mRNA expressions of apoptotic molecules, cytochrome C, and caspase-3 were attenuated upon fisetin administration. The findings suggest that fisetin shows a neuroprotective effect by suppressing the release of inflammatory and apoptosis molecules and attenuating histological alterations during experimental epilepsy.

Rutin prevents seizures in kainic acid-treated rats: evidence of glutamate levels, inflammation and neuronal loss modulation

“…38,66 Therefore, the suppression of inflammatory molecule release and the related signaling pathway in the brain has been suggested to be an important mechanism underlying the antiepileptic and neuroprotective effects. 67,68 In the present study, we observed the activation of astrocytes and increased IL-1β, IL-6, TNF-α, HMGB1, IL-1R1, and TLR4 protein expression levels in the hippocampi of KA-treated animals, which is in line with previous studies (Kołosowska et al , 2014; Khatoon et al , 2021). 68,69 Furthermore, a significant decrease in the number of activated astrocytes was observed following rutin pretreatment in KA-treated rats, suggesting that rutin attenuates KA-induced astrogliosis.…”

Betahistine Attenuates Seizures, Neurodegeneration, Apoptosis, and Gliosis in the Cerebral Cortex and Hippocampus in a Mouse Model of Epilepsy: A Histological, Immunohistochemical, and Biochemical Study

“…TNF- α and IL-1 β levels were significantly higher in the PTZ group in this investigation. These findings matched those of recent research of Khatoon et al (2021), who found comparable outcomes in the brains of mice with PTZ-induced kindling. Aronica et al, (2017) attributed this increase to activated astrocytes and microglia in epilepsy that released cytokines, including IL-1 β and TNF- α causing neuron hyperexcitability.…”

Sexual Dimorphic Metabolic and Cognitive Responses of C57BL/6 Mice to Fisetin or Dasatinib and Quercetin Cocktail Oral Treatment

“…Administration of senolytic compounds is a novel approach to removing senescent cell accumulation and thereby reducing inflammation. These compounds are being investigated as potential lifespan and healthspan extending therapies and may also have applications in the treatment of numerous metabolic and neurodegenerative disorders (18,(23)(24)(25). Since Fisetin and Q are naturally occurring plant flavonoids, they are readily available as dietary supplements for use without a prescription.…”

“…This has been observed after reducing senescent cell burden in progeroid or aged (twenty-four-month-old) C57BL/6 mice (20-22). Moreover, deletion of senescent cells from the brain genetically or pharmacologically with senolytic drugs led to functional improvements in mouse models of neurodegenerative diseases such as Parkinson’s and Alzheimer’s disease (18, 23-25). These studies have shown senotherapeutics can reduce senescent cell burden and have positive impacts on animals with accelerated aging, advanced age, or neurodegenerative disorders.…”