Abstracts

Rationale: Inflammatory responses by brain have been shown to be involved in both seizure occurrence and epileptogenesis, implying that the mediators of inflammatory pathway may form new molecular targets for antiepileptic drugs. Anticonvulsant drugs are a diverse group of compounds widely used in the treatment of epileptic seizures. ; their anti-inflammatory ability has, however, rarely been studied. Therefore, we used in vitro tissue culture system to screen anticonvulsant drugs that not only inhibit the symptoms of epilepsy, but also prevent or abrogate the inflammatory wing of disease pathogenesis. Methods: Mouse microglia cell line BV-2 and mixed primary mouse glial culture (containing more 50% of microglia cells as determined by flow cytometry) were used in this study. After determining the time course of drug effects, cells were pretreated with corresponding anticonvulsant drugs for 1-2 h and then stimulated with various amount of lipopolysaccharides (LPS) for 24 h in the presence of anticonvulsant drugs. After 24 h of treatment, the culture supernatants were harvested for cytokine assays with ELISA, and the total RNAs extracted from the cells were subjected to quantitative real-time PCR assay of cytokine gene expressions. The cell viability was also detected with MTS assay to measure the cytotoxicity of anticonvulsant drugs at various dosages. The anticonvulsant drugs tested so far included gabapentin, valproate, carbamazepine, topiramate, and carisbamate; the synthetic immunosuppressant dexamethasone was used as positive control. Results: While dexamethasone exhibits potent inhibitory effects on LPS-stimulated inflammatory cytokine secretion from BV-2 cells and primary glial cultures, gabapentin, valproate, carbamazepine, and topiramate fail to show significant anti-inflammatory effect on both cell line and primary culture. However, the experimental anticonvulsant drug, carisbamate, displays a significant inhibition of LPS-induced TNF-α and IL-6 production in BV-2 cells, and such inhibitory effect on IL-6 secretion is confirmed in primary glial culture too. The cell viability test indicates that all the cells are viable under the dosages applied. Conclusions: The results of our anti-inflammation screening of anticonvulsant drugs indicates that most conventional drugs show no such effect as expected , , because the generation of anticonvulsant drugs was irrelevant with anti-inflammation. Carisbamate, on the other hand, demonstrated the anti-inflammatory effect in our in vitro system.. our data indicate that although anti-inflammation is overlooked during the development of anticonvulsant drugs as an irrelevant trait, they may accidentally exert such effect, like carisbamate; therefore, to expand our screening with more candidate drugs and to integrate the anti-inflammatory screening into the future research and development of anticonvulsant drugs may have the potential to discover existing drugs or obtain novel compounds that not only inhibit the epileptic symptoms, but also prevent the inflammatory pathogenesis of the epilepsy.