Pharmacokinetic, pharmacodynamic, and neurochemical investigations of lamotrigine-pentylenetetrazole kindled mice to ascertain it as a reliable model for clinical drug-resistant epilepsy

Adjunct antiseizure effect of clotrimazole in a rotenone corneal kindling mouse model of mitochondrial drug-resistant epilepsy

This study aimed to investigate the therapeutic potential of clotrimazole, an inhibitor of the transient receptor potential cation channel, for treating mitochondrial drug-resistant epilepsy and to understand its underlying neurochemical mechanisms. Adult albino mice underwent rotenone-corneal kindling, receiving daily electric shocks (15 mA, 20 V, 6-Hz for 3 s) through a corneal electrode, to induce mitochondrial drug-resistant epilepsy. The onset of drug resistance was confirmed by the significant (p < 0.05) lack of seizure control with standard antiseizure medications including levetiracetam (40 mg/kg), valproate (250 mg/kg), phenytoin (35 mg/kg), lamotrigine (15 mg/kg), and carbamazepine (40 mg/kg). Drug-resistant mice were then classified into one vehicle-treated group and three groups treated with varying doses of clotrimazole (40, 80, and 160 mg/kg orally). Neurochemical analysis of the seizurogenic hippocampus and cerebral cortex was conducted using high-performance liquid chromatography with an electrochemical detector. Administration of clotrimazole alongside standard antiseizure medications led to a significant decrease (p < 0.05) in seizure scores suggesting the restoration of antiseizure effects. Neurochemicals, including tryptophan, serotonin, kynurenine, serine, taurine, gamma-aminobutyric acid, and glutamate, were significantly restored post-clotrimazole treatment. Overall, the present study underscores the adjunct antiseizure effect of clotrimazole in a rotenone corneal kindling mouse model of mitochondrial drug-resistant epilepsy, emphasising its role in neurochemical restoration.

Ceftriaxone and selenium mitigate seizures and neuronal injury in pentylenetetrazole-kindled rats: Oxidative stress and inflammatory pathway

Epilepsy is one of the most serious worldwide neurological disorders that lead to the cognitive-psychosocial insults in recurrent seizures. About one third of the patients are drug-resistant, so innovative drugs are needed to manage seizures to improve the quality of life. Ceftriaxone is a cephalosporin antibiotic that increases the expression of glutamate transporters-1 and improves the neurobehavioral effects caused by increased glutamate level in the CNS. Selenium is well known antioxidant. The present study aimed to investigate ceftriaxone and selenium therapeutic effects against epilepsy in rats. Epilepsy was induced by PTZ given at a dose (50 mg/kg I.P) on alternative days for 13 days. Eighty rats were randomly divided into 8 groups: Group1-2; normal and vehicle control, Group 3; PTZ group, Group 4-8; kindled rats received selenium, ceftriaxone100, ceftriaxone200, selenium + ceftriaxone100 and selenium + ceftriaxone200 mg/kg/day respectively for a week. At the end of the study, behavioral tests were performed. Oxidative stress, inflammatory markers, neurotransmitters and GLT-1 were measured in brain tissue homogenate. Brain histopathological investigation was also done. PTZ-kindled rats exhibited increased Racine score, besides behavioral tests and histopathological changes, significant elevation in oxidative stress and inflammatory markers, with decrease in serotonin, dopamine, GABA levels and GLT-1 expressions. Selenium and Ceftriaxone alone or combined treatment decreased Racine score with remarkable improvement in behavioral and histopathological changes. The antioxidant enzymes, neurotransmitters and GLT-1 expressions were increased, along with reduced TNF-α, IL-1 levels. Current study showed that selenium + ceftriaxone100 group represents a possible approach to improve epilepsy particularly through inhibiting oxidative stress and inflammation.

Frontline Sodium Channel-Blocking Antiseizure Medicine Use Promotes Future Onset of Drug-Resistant Chronic Seizures

The mechanisms of treatment-resistant epilepsy remain unclear. We have previously shown that frontline administration of therapeutic doses of lamotrigine (LTG), which preferentially inhibits the fast-inactivation state of sodium channels, during corneal kindling of mice promotes cross-resistance to several other antiseizure medicines (ASMs). However, whether this phenomenon extends to monotherapy with ASMs that stabilize the slow inactivation state of sodium channels is unknown. Therefore, this study assessed whether lacosamide (LCM) monotherapy during corneal kindling would promote future development of drug-resistant focal seizures in mice. Male CF-1 mice (n = 40/group; 18-25 g) were administered an anticonvulsant dose of LCM (4.5 mg/kg, i.p.), LTG (8.5 mg/kg, i.p.), or vehicle (0.5% methylcellulose) twice daily for two weeks during kindling. A subset of mice (n = 10/group) were euthanized one day after kindling for immunohistochemical assessment of astrogliosis, neurogenesis, and neuropathology. The dose-related antiseizure efficacy of distinct ASMs, including LTG, LCM, carbamazepine, levetiracetam, gabapentin, perampanel, valproic acid, phenobarbital, and topiramate, was then assessed in the remaining kindled mice. Neither LCM nor LTG administration prevented kindling: 29/39 vehicle-exposed mice were kindled; 33/40 LTG-exposed mice were kindled; and 31/40 LCM-exposed mice were kindled. Mice administered LCM or LTG during kindling became resistant to escalating doses of LCM, LTG, and carbamazepine. Perampanel, valproic acid, and phenobarbital were less potent in LTG- and LCM-kindled mice, whereas levetiracetam and gabapentin retained equivalent potency across groups. Notable differences in reactive gliosis and neurogenesis were also appreciated. This study indicates that early, repeated administration of sodium channel-blocking ASMs, regardless of inactivation state preference, promotes pharmacoresistant chronic seizures. Inappropriate ASM monotherapy in newly diagnosed epilepsy may thus be one driver of future drug resistance, with resistance being highly ASM class specific.

Bioinformatics guided rotenone adjuvant kindling in mice as a new animal model of drug-resistant epilepsy

Drug-resistant epilepsy results from multiple mechanisms which are difficult to fully acquire in animal models. Technological advances, that allow transformation of big data into novel therapies, are now assisting in identification a disease targets for animal modeling. Our goal was to transform the available genomic and proteomic data related to drug-resistant epilepsy into ubiquitous disease target using system biology and network pharmacology approaches, followed by animal modeling and assess its validity. We used a dataset of 42 antiseizure drugs, 175 drug targets, and 601 epilepsy-gene associations to create interactome of 543 diseased proteins linked to drug-resistant epilepsy. DIAMOnD algorithm and DAVID web-services were used to identify 35 disease pathways whereby mitochondrial complex-I was selected for animal modeling. Albino mice were treated with specific inhibitor of mitochondrial complex-I (i.e., rotenone 2.5 mg/kg, i.p on daily basis) along with chemical and electric kindling stimulus for 35 days and 15 days, respectively. According to our results, the rotenone kindling model with inhibited complex-I activity showed significant (P < 0.001) resistance to lamotrigine (15 mg/kg), levetiracetam (40 mg/kg), carbamazepine (40 mg/kg), zonisamide (100 mg/kg), gabapentin (224 mg/kg), pregabalin (30 mg/kg), phenytoin (35 mg/kg), topiramate (300 mg/kg), valproate (200 mg/kg), and drug combinations at doses that had significantly (P < 0.001) controlled seizure severity in lamotrigine-pentylenetetrazole and corneal kindling models. In conclusion, lamotrigine kindling model is more advantageous than earlier described lamotrigine and corneal kindling models which respond to drug combinations. As a result, pre-clinical drug screening through rotenone kindling may uncover broad spectrum drugs with novel antiseizure mechanisms which is a pressing issue to deal with drug-resistant epilepsy.

PTZ kindling model for epileptogenesis, refractory epilepsy, and associated comorbidities: relevance and reliability

Pentylenetetrazole (PTZ)-induced seizure is one of the gold standard mouse models for rapid evaluation of novel anticonvulsants. Synchronically, PTZ induced kindling in mice is also a simple and well accepted model of chronic epilepsy. PTZ kindling has been explored for studying epileptogenesis, epilepsy-associated comorbidities, and refractory epilepsy. This review summarizes the potential of PTZ kindling in mice and its modifications for its face, construct, and predictive validity to screen antiepileptogenic drugs, combined or add on novel and safe therapies for treatment of epilepsy-associated depression and cognitive impairment as well as effective interventions for pharmacoresistant epilepsy.