Zebrafish model for epilepsy

To explore the presence of potential seizure-inducing compounds in the CSF, a zebrafish model was utilized (Liu et al., 2019, Pham et al., 2016, Purdie et al., 2009). This model has been used in the past as a high throughput screening method for potential neurotoxic or seizure-inducing properties of chemical compounds or toxins (Pham et al., 2016, Purdie et al., 2009), as well as to investigate novel anti-epileptic compounds (Liu et al., 2019). Briefly, 2 nl of CSF from a person with recent onset of nodding seizures (case 6, Table 1), 2 nl from a person with more advanced disease without nodding seizures (case 13, Table 1), and 2 nl from a European control without epilepsy were injected into the heart of 10 larvae at 3 days post-fertilization (dpf) and into the peritoneum of 10 larvae at 7 dpf. The CSF from the selected cases was diluted 1:10 v/v in larval medium (Danieau’s solution, 1.5 mM HEPES, 17.4 mM NaCl, 0.21 mM KCl, 0.12 mM MgSO₄, and 0.18 mM Ca(NO₃)₂ and 0.6 μM methylene blue) and three zebrafish larvae at 3 dpf were kept in this solution in a 96-well plate. All larvae were kept at 28 °C in an incubator in dark conditions and monitored microscopically for 1 min every hour on the first day and once every day in the week following exposure for the potential development of seizures, abnormal swimming behaviour, or signs of toxicity, such as abnormal heart rate, unresponsiveness to touch, or death.

Summary of the clinical characteristics of study participants.

Mf, microfilariae; F, female; M, male.