Background: The present study analyzed the neuroprotective effects of topiramate on 6-hydroxydopamine (6-OHDA)–induced toxicity in primary dopaminergic mesencephalic neuronal cell cultures.
Material/Methods: Through the use of tyrosine hydroxylase and microtubule-associated protein 2 immunocytochemistry, the morphology and development of dopaminergic neurons was observed. Hoechst33258 and propidium iodide (PI) double staining was used to determine cell membrane penetrability and apoptosis by fluorescent microscopy. Methyl thiazole tetrazolium was used to assay cell viability and metabolism. The cells were assigned to 3 groups: (1) control: primary cultured neurons; (2) 6-OHDA: primary cultured neurons and 6-OHDA; and (3) topiramate (TPM) protection: primary cultured neurons and 6-OHDA, treated with various concentrations (10, 50, and 100 µM) of TPM.
Results: Hoechst 33258 and PI double immunofluorescence revealed that the number of dying cells after 6-OHDA treatment was greater than after TPM treatment. Compared with the 6-OHDA group, there were more neurons with greater cell viability in the 6-OHDA plus TPM group.
Conclusions: Topiramate was shown to provide protection to dopaminergic neurons exposed to 6-OHDA by reducing cell apoptosis and enhancing cell viability. The neuroprotective effects of TPM were dose-dependent.

Keywords: Propidium - metabolism, Neuroprotective Agents - pharmacology, Neurons - metabolism, Microtubule-Associated Proteins - metabolism, Fructose - pharmacology, Formazans - metabolism, Fluorescent Antibody Technique, Dopamine - metabolism, Cell Shape - drug effects, Cell Proliferation - drug effects, Cell Death - drug effects, Cell Count, Bisbenzimidazole - metabolism, Staining and Labeling, Tetrazolium Salts - metabolism, Tyrosine 3-Monooxygenase - metabolism