Exploring DHODH inhibition with silibinin as a promising approach to treat drug resistance in epilepsy.

Mitochondrial dysfunction and excessive production of reactive oxygen species (ROS) are key contributors to the pathogenesis of drug resistant epilepsy (DRE). Recent findings suggest DHODH, a mitochondrial enzyme may influence neuronal excitability by affecting intrinsic firing set points. Dysregulated DHODH activity may elevate set points, contributing to persistent hyperexcitability in epilepsy. This study aims to explore the potential of DHODH inhibition as a therapeutic strategy to control seizures in drug resistant epilepsy. DRE was developed by administering rotenone 2.5 mg/kg i.p. once, followed by corneal kindling twice daily. Pre-treatment resistance validation was done with standard antiseizure drugs (ASD's) following treatment with standard drug leflunomide (20 mg/kg) and test drug silibinin (100, 200, and 400 mg/kg) for 10 days. Further post-treatment resistance validation was done and animals were sacrificed on 35th day. Brain samples were preserved for estimation of DHODH levels, Complex I activity, ATP, GSH and TBARS levels. A significant increase in DHODH activity and TBARS levels along with a corresponding decrease in complex I activity, ATP, and GSH levels was observed in the RCK model of DRE. Treatment with silibinin effectively attenuated the drug resistance as evident by reduced seizure severity as inhibition of DHODH dose-dependently. This was further supported by normalisation of mitochondrial redox status in RCK mouse model of DRE. Silibinin serves as a promising therapeutic agent for DRE by inhibiting DHODH, a key enzyme involved in mitochondrial dysfunction and neuronal hyperexcitability.