Anticonvulsive evaluation and histopathological survey of thalidomide synthetic analogs on lithium-pilocarpine-induced status epilepticus in rats

Background and purpose: Status epilepticus is a severe neurological disorder that can be life-threatening. Thalidomide and its analogs have shown promising results to confront pentylenetetrazole-induced seizures. This study aimed to evaluate the potential effects of three synthesized thalidomide derivatives on lithium-pilocarpine-induced status epilepticus. Experimental approach: To induce status epilepticus, rats received lithium chloride (127 mg/kg, i.p.) and pilocarpine HCl (60 mg/kg, i.p.) 20 h after lithium chloride injection. Thirty min before pilocarpine HCl administration, rats received hyoscine N-butyl bromide (1 mg/kg, i.p.) and concurrently one of the test compounds (5B, 5C, and 5D), diazepam, thalidomide, or vehicle (4% DMSO) to evaluate their anti-epileptic effects. Epileptic seizures scores were assessed through the Racine scale. Twenty-four h after injection of pilocarpine, brain samples were extracted for further histopathological evaluation. Findings/Results: Results revealed that among tested compounds (5B, 5C, and 5D), only compound 5C (1 mg/kg) exhibited excellent anti-epileptic activity comparable to diazepam (10 mg/kg). Compound 5D (100 mg/kg) only demonstrated comparable anti-epileptic activity to thalidomide (1 mg/kg). Compound 5B did not have any anti-epileptic activity even at the dose of 100 mg/kg. The histopathological survey showed that compound 5C has more neuroprotective effects than diazepam and thalidomide in the cortex of the brain. In the cornu ammonis 1 region, thalidomide had higher protective properties and in the cornu ammonis 3 and dentate gyrus areas, diazepam had higher efficacy to prevent necrosis. Conclusion and implications: Compound 5C is a good candidate for further studies regarding its potency, compared to thalidomide and diazepam.