ABSTRACT
Valproic acid induced teratogenicity at genetic and somatic levels, the action mechanism is still unclear. We hypothesized that folate receptor gene (folr1) and others may be interacting to elicit neural tube defect (NTD), while N-acetylcysteine (NAC) may be beneficial for protection. In chicken embryo model, the experiment was conducted in two parts. The first part was carried out to test the optimum dose of VPA. The second part was conducted to test the protective effect of NAC at doses 10 and 20 mM. VPA induced dysvascularization, incomplete somite enclosure, histone deacetylase (HDAC) inhibition, folate deficiency, homocysteine accumulation, SOD inhibition, glutathione depletion, elevated MDA and hydrogen peroxide. NAC alleviated most of these adverse effects. The microarray analysis revealed 17 genes downregulated and four upregulated. The relevancy covered translation (23%), signal transduction (23%), transcription (16%), cell adhesion (16%), neural cell migration (8%), transport (7%), and organismal development (7%). The genes insulin-like growth factor 2 receptor gene (IGF2R), regulator of G-protein signaling 4 gene (RGS4), alpha 3 (VI) collagen gene (COL6A3), endothelin receptor type b gene (EDNRB), and Krüppel-like factor 6 gene (KLF6) substantially downregulated in reality were directly intermodulating and associated with NTD. VPA downregulated folr1 gene in a dose responsive manner without affecting pax-3 gene, which was ascribed to the metahypoxic state. Conclusively, VPA affects 21 genes: 17 downregulated and four upregulated. VPA dose responsively downregulates gene folr1 without affecting pax-3 gene. These adverse effects can be partially alleviated by N-acetylcysteine.
