A delayed sequential treatment protocol provides effective neuroprotection for sarin-induced status epilepticus in rats
Lazar Shlomi, Neufeld-Cohen Adi, Egoz Inbal, Baranes Shlomi, Gez Rellie, Glick Pnina, Cohen Maayan, Gutman Hila, Chapman Shira, Kraus Dror, Gore ArielAbstract
Objectives
Status epilepticus (SE) following sarin exposure represents a critical therapeutic challenge, as delayed treatment with benzodiazepines often fails to prevent prolonged seizures and subsequent brain injury. This study evaluated a delayed treatment protocol combining ketamine and midazolam, followed by the sequential administration of either valproate or levetiracetam, in reducing electrographic seizure activity (ESA), mortality, and long-term neuropathology in a rat model of sarin-induced SE.
Methods
SE was induced in rats by exposure to 1.2 LD₅₀ sarin, followed one minute later by atropine and TMB4 (TA) treatment to prevent cardiopulmonary arrest. Thirty minutes after exposure, ketamine and midazolam were administered, followed 30 min later by either valproate or levetiracetam, simulating field treatment to hospital care. Outcomes were compared with delayed midazolam monotherapy and a simultaneous triple-treatment regimen consisting of ketamine, midazolam, and valproate. ESA and mortality were monitored for one week. Behavioral assessments were performed two weeks post-exposure, followed by biochemical and histopathological analyses at five weeks.
Key Findings
Compared with TA treatment alone or TA combined with delayed midazolam monotherapy, both the simultaneous and sequential triple-treatment regimens significantly reduced mortality, shortened ESA duration, and improved post-exposure weight recovery. The treatments also reduced neuroinflammatory and neuronal injury markers, including prostaglandin E₂ (PGE₂) and translocator protein (TSPO). In addition, they attenuated gliosis, astrocytosis, and neuronal damage and normalized the sarin-induced increase in open-field activity.
Conclusions
Delayed sequential triple therapy effectively mitigated seizure activity, neuroinflammation, and long-term neuropathology. These findings support the preclinical development of sequential multidrug treatment strategies and warrant to evaluate their translational potential.