Abstract
BACKGROUND: Valproic acid (VPA) is known for its broad-spectrum antiepileptic effects and is recommended for generalized epilepsy, in contrast to phenytoin, which has a more limited spectrum. This study investigated the cytotoxic and inflammatory responses to phenytoin and VPA in peripheral blood mononuclear cells (PBMCs), with and without bacterial lipopolysaccharide (LPS) stimulation. METHODS: PBMCs from healthy donors were divided into 12 groups: control (Ctrl), phenytoin (Phy), and four concentrations of VPA (Val-50, Val-75, Val-100, Val-200), with and without LPS. Assessments were conducted on days 1 and 3, including total, live, and dead cell counts, cell viability, and lactic acid dehydrogenase (LDH) cytotoxicity assays. Inflammatory mediators (IL-6, IL-1β) and immune markers (IL-18, IgA) were measured using enzyme-linked immunosorbent assay (ELISA) on day 3. Statistical analysis involved two-way ANOVA, Tukey's HSD tests, and paired t-tests. RESULTS: All treatment groups showed significant declines in cell counts and viability from day 1 to day 3, which were exacerbated by LPS. Val-50 + LPS maintained higher cell counts compared to Ctrl + LPS and Phy + LPS. Elevated LDH levels were primarily observed in the Val-100 and Val-200 groups, with and without LPS. In the absence of LPS, the Val-75 and Val-100 groups showed notable reductions in IL-18 and IgA levels, while all VPA treatments reduced IL-6 levels compared to controls. This effect was enhanced under LPS exposure, although IL-1β reductions in the Val-75, Val-100, and Val-200 groups were reversed in the presence of LPS. Val-75 demonstrated lower cytotoxic and inflammatory responses compared to Phy and higher VPA doses, showing moderate LDH increases and reduced IL-18, IgA, IL-1β, and IL-6 levels, particularly under LPS challenge. CONCLUSION: Phenytoin and VPA induced significant cytotoxic and inflammatory responses, influenced by dosage and LPS exposure. Val-75 exhibited a dose-specific immunomodulatory effect, reducing both pro-inflammatory and immune markers.