The contribution of S100B to the glioprotective effects of valproic and arundic acids.

Valproic and arundic acids are astrocytes-modulating agents with potential effects in the treatment of Alzheimer's disease (AD). S100B is an astrocytic cytokine with a possible role in the pathogenesis of AD. In this study, we aimed to assess the glioprotective effects of valproic and arundic acids against amyloid-β-peptide (Aβ)-induced glial death and contribution of S100B to the glioprotective effects of these agents in an astrocytic culture. We used Aβ25-35 at a concentration of 200 μM in 1321N1 astrocyte cells. We treated the cells with valproic acid (0.5 and 1 mM) and/or arundic acid 50 µM for 24 hr. Methylthiazolyldiphenyl-tetrazolium bromide (MTT) test was used to measure cell viability. The intracellular and extracellular S100B levels were measured using an ELISA kit. The data were analyzed using one-way analysis of variance followed by the Tukey's test. Aβ (200 µM) decreased the cell viability compared to the control group (P<0.001). Valproic acid (0.5 and 1 mM) and arundic acid (50 µM) ameliorated the gliotoxic effects of Aβ (P<0.05). The Aβ-treated group had higher S100B levels (both intracellular and extracellular) compared to the negative control groups (P<0.001). Arundic and valproic acids (0.5 and 1 mM) decreased both the intracellular and extracellular S100B levels compared to the Aβ-treated group (P<0.001). By considering homeostatic and neuroprotective functions of astrocyte, the astroprotective effects and the attenuation of S100B level may be responsible, at least in part, for the beneficial effects of valproic and arundic acids in AD.