Effects of Selenium and Topiramate on Cytosolic Ca2+ Influx and Oxidative Stress in Neuronal PC12 Cells

It has been widely suggested that selenium (Se) deficiency play an important role in the pathophysiology of epilepsy. It has been reported that Se provides protection against the neuronal damage in patients and animals with epilepsy by restoring the antioxidant defense mechanism. The neuroprotective effects of topiramate (TPM) have been reported in several studies but the putative mechanism of action remains elusive. We investigated effects of Se and TPM in neuronal PC12 cell by evaluating Ca2+ mobilization, lipid peroxidation and antioxidant levels. PC12 cells were divided into eight groups namely control, TPM, Se, H2O2, TPM + H2O2, Se + H2O2, Se + TPM and Se + TPM + H2O2. The toxic doses and times of H2O2, TPM and Se were determined by cell viability assay which is used to evaluate cell viability. Cells were incubated with 0.01 mM TPM for 5 h and 500 nM Se for 10 h. Then, the cells were exposed to 0.1 mM H2O2 for 10 h before analysis. The cells in all groups except control, TPM and Se were exposed to H2O2 for 15 min before analysis. Cytosolic Ca2+ release and lipid peroxidation levels were higher in H2O2 group than in control, Se and TPM combination groups although their levels were decreased by incubation of Se and TPM combination. However, there is no difference on Ca2+ release in TPM group. Glutathione peroxidase activity, reduced glutathione and vitamin C levels in the cells were lower in H2O2 group than in control, Se and TPM groups although their values were higher in the cells incubated with Se and TPM groups than in H2O2 groups. In conclusion, these results indicate that Se induced protective effects on oxidative stress in PC12 cells by modulating cytosolic Ca2+ influx and antioxidant levels. TPM modulated also lipid peroxidation and glutathione and vitamin C concentrations in the cell system.