Optimization of pilocarpine-mediated seizure induction in immunodeficient NodScid mice

Abstract

Temporal lobe epilepsy (TLE) has been modeled in mice using pilocarpine induction, with variable results depending on specific strains. To allow efficient xenotransplantation for the purpose of optimizing potential cell-based therapy of human TLE, we have determined the optimal dosing strategy to produce spontaneous recurring seizures in immunodeficient NodScid mice. Multiple 100mg/kg injections of pilocarpine have been shown to be more effective than single 300-400mg/kg injections for inducing spontaneous seizures in NodScid mice. Under our optimal conditions, 88.1 ± 2.9% of the mice experienced status epilepticus (SE) with a survival rate of 61.8 ± 5.9%. Surviving SE mice displayed spontaneous recurrent seizures at a frequency of 2.8 ± 0.9 seizures/day for a duration of 41.1 ± 3.5s. The widely used method of a single injection of pilocarpine was significantly less efficient in inducing seizures in NodScid mice. Therefore, we have determined that a multiple injection "ramping up" of 100mg/kg of pilocarpine is optimal for inducing TLE-like spontaneous seizures in NodScid mice. Using this method, mice with SE efficiently developed SRS and expressed mossy fiber sprouting, a signature histopathological feature of TLE.

Keywords: Mossy fiber sprouting; NodScid mice; Pilocarpine; Seizure; Temporal lobe epilepsy.