It has been suggested that the intelligence quotient of children born to pregnant women taking 1000 mg or more of valproic acid per day is lower than that of children born to pregnant women taking other antiepileptic drugs. However, the mechanism whereby intelligence quotient is decreased in children exposed to valproic acid during the fetal period has not yet been elucidated. Therefore, we used the human neuroblastoma cell line SH-SY5Y to evaluate the effects of antiepileptic drugs containing valproic acid on nerve cells. We assessed the anti-proliferative effects of drugs in these cells via WST-8 colorimetric assay, using the Cell Counting Kit-8. We also quantified drug effects on axonal elongation from images using ImageJ software. We also evaluated drug effects on mRNA expression levels on molecules implicated in nervous system development and folic acid uptake using real-time PCR. We observed that carbamazepine and lamotrigen were toxic to SH-SY5Y cells at concentrations >500 μM. In contrast, phenytoin and valproic acid were not toxic to these cells. Carbamazepine, lamotrigen, phenytoin, and valproic acid did not affect axonal outgrowth in SH-SY5Y cells. Sodium channel neuronal type 1a (SCN1A) mRNA expression-level ratios increased when valproic acid was supplemented to cells. The overexpression of SCN1A mRNA due to high valproic acid concentrations during the fetal period may affect neurodevelopment. However, since detailed mechanisms have not yet been elucidated, it is necessary to evaluate it by comparing cell axon elongation and SCN1A protein expression due to high-concentration valproic acid exposure.
Keywords: Antiepileptic drugs; Nerve cell; SCN1A; Teratogenicity; Valproic acid.
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