Regulating the NMDA/NR2B signaling pathway mediates anticonvulsant, antineuroinflammation, and anti-oxidative stress effects of 1,3,benzothiazole derivative 1M in pentylenetetrazole-induced kindling in mice

Naunyn Schmiedebergs Arch Pharmacol. 2024 Oct 15. doi: 10.1007/s00210-024-03522-9. Online ahead of print.

Abstract

Periodic epileptic episodes are the hallmark of epilepsy, a prevalent neurological disorder. Research suggests a significant correlation between neuroinflammation and oxidative stress in a variety of neurological diseases, such as epilepsy. A substantial amount of evidence supports the role of N-methyl-D-aspartate receptors (NMDARs) in the progression of epilepsy. Although several lines of research have disclosed numerous biochemical effects of early seizures, its connection with disturbed NMDAR/NR2B subunit expression remains unclear. 2-Mercaptobenzothiazole (MBT) is a vital scaffold with several biological activities, and its various substitutes show promising anti-inflammatory potential. The current study aimed to investigate the newly synthesized 1,3-(benzothiazole-2-sulfanyl)-1-(morpholine-4-yl)ethan-1-one (1 M), a substituted MBT, for its neuroprotective potential in a mice model of pentylenetetrazole-induced epilepsy (PTZ), by modulating NMDA/NR2B pathway. The compound was tested for docking and simulation analysis, demonstrating a solid and stable bond with the NR2B subunit of NMDA. To ascertain the effects of 1 M, as well as to further illustrate its mechanism of neuroprotection via NMDA/NR2B in PTZ-induced kindling model, mice of either sex were given two doses of test compound, 1 M (10 mg/kg and 20 mg/kg). The behavioral assessments were evaluated using open-field, Y-maze, and elevated-plus maze tests, which indicated improved behavioral alterations caused by PTZ after 1 M treatment. The antioxidant profiling was done by estimating glutathione-S-transferase (GST), catalase (CAT), reduced glutathione (GSH), and LPO (lipid peroxidation) in hippocampal tissues, where the test compound 1 M significantly restored the depleted antioxidants, showcasing its antioxidant potential. Moreover, the cellular morphological damages induced by PTZ were detected by H&E staining, which was rescued after 1 M administration. Furthermore, the activation of the inflammatory pathway was confirmed by quantitative analysis of inflammatory mediators tumor necrotic factor (TNF-α), nuclear factor kappa B (NF-κB), and cylooxegenase2 (COX-2) by enzyme-linked immunosorbent assay (ELISA), where 1 M administration significantly ameliorated their expression. Furthermore, to demonstrate the involvement of the NR2B pathway, NR2B-antagonist ifenprodil was employed, and results were further confirmed through RT-PCR analysis. Our results, when considered collectively, indicate that 1 M may act by inhibiting the NR2B subunit of the NMDA receptor, subsequently mitigating downstream oxidative stress and inflammatory mediators through various pathways.

Keywords: Anti-inflammatory; Antioxidant; Epilepsy; Ifenprodil; NMDA; NR2B.