Increased susceptibility for pathogenesis of post-traumatic epilepsy in offspring exposed to deltamethrin during gestation and ameliorative effects of dietary curcumin

Deltamethrin (DLT) is a most potent and widely used pesticide that does not cross Blood Brain Barrier (BBB) in adults. While it considered as safe, its lipophilic properties makes it a neurotoxic substance specially in early stages of brain development. It has shown neurotoxic effects on the brain by hyper-excitation of neurons. Epilepsy is a neurological disorder with recurring seizures where epileptogenesis occurs due to hyperexcitation of neurons. In various kinds of epilepsy, post-traumatic epilepsy (PTE) is a common epilepsy in children due to traumatic brain injury (TBI). PTE, however reportedly alleviated by curcumin in rats. Therefore, in the current study, we assessed the effect of gestational DLT exposure on the severity of PTE. The pregnant rats were injected with 0.75mg/kg-b/w of DLT dissolved in 1% DMSO each day of gestation between days 7-15. Epilepsy was induced four months postnatally, and curcumin was orally administered by oral gavage. ECoG, behavioral tests, Golgi Staining, immunofluorescence, and immunohistochemistry was performed to assess the pathogenesis, severity of epilepsy, and mitigating effects of curcumin. The results indicated the neurotoxic effects of DLT by raising the severity of seizures in an electrophysiological and behavioral manner. PTE decreased the dendritic branching and arborization. Sodium channel overexpression is an important reason for the hyperexcitation of neurons during the pathogenesis of epilepsy. DLT enhanced the increase in expression of both sodium channel subunits NaV1.1 and NaV1.6 during epileptogenesis. Similarly, synaptic markers PSD95 and SYP decreased. Astrocytic and microglial activation increased during pathogenesis of PTE. The antiepileptic effects of curcumin alleviated the effects on electrobehavioral response, neuronal arborization, and levels of NaVs, PSD95, SYP, GFAP and Iba1 in epilepsy. However, DLT raised the severity and susceptibility of epilepsy and decreased the antiepileptic effects on gestationally DLT-exposed epileptic animals. Our result demonstrates the gestational neurotoxic exposure of DLT increased the severity and susceptibility for PTE while decreasing the antiepileptic effects of curcumin.