Effects of two different compounds on seizure suppression using the zebrafish PTZ-seizure model

Epilepsies are a common and severe neurological condition characterized by spontaneous and recurrent seizures. Although anti-seizure medications are effective for most patients, about 30% remain pharmacoresistant. Moreover, uncontrolled seizures are associated with risk factors and shortened life expectancy for individuals with refractory epilepsy. Preclinical studies are an essential step for drug discovery and the zebrafish ( Danio rerio ) has been successfully employed for this purpose. In this study, we applied the zebrafish PTZ-seizure model to investigate the effect of two compounds on seizure suppression, Tripeptide (p-BTX-I) and the Cx43 peptide CX2. Zebrafish larvae at 6 days post-fertilization (dpf) were exposed to both compounds, according to their group, 24h prior to PTZ-seizure induction. We quantified the compounds’ effect on seizure latency, number of seizures and transcript levels of genes related to inflammation, oxidative stress, and apoptosis ( il1b, tnfa, cox1, cox2a, il6, casp3a, casp9, baxa, bcl2a, nox1, sod1 and cat ).

Our results showed that CX2 at a concentration of 0.1 μM/mL yielded the best outcome for seizure suppression as it reduced the number of seizures and increased the seizure latency. Additionally, CX2 treatment before PTZ-induced seizures decreased the transcript of il1b, il6, tnfa and cox1 genes, all related to inflammation. A bio-distribution study showed that the CX2 reached the zebrafish brain at both times investigated, 1h and 6h. Similarly, the tripeptide exhibited anti-inflammatory and anti-apoptotic action, reducing mRNA expression of the il1b and casp9 genes. Our findings suggest that both Tripeptide and CX2 hold translational potential for seizure suppression.