Retinal ganglion cell toxicity due to oxcarbazepine and valproic acid treatment in rat

PURPOSE To evaluate and to compare the possible toxic effects of oxcarbazepine (OXC) and valproic acid (VPA) on retinal ganglion cells (RGCs) in rat. METHODS Forty female Wistar rats (21-24 days old and weighted between 44.6 and 57.3g) were divided equally into 4 experimental groups which were applied tap water (group 1), 300mg/(kgday) VPA (group 2), 100mg/(kgday) OXC (group 3), and both VPA and OXC (group 4) via gavage for 90 days. Enucleation was performed for histopathologic analysis. RGCs were counted under the light microscopic examination. RESULTS RGC numbers in OXC and combined OXC-VPA groups were found to be lower than those of control group. On the other hand RGC number was comparable with those of control group in VPA group. CONCLUSION OXC seems to be toxic to RGCs at 100mg/kg dose when it is been given as a monotherapy or combined with VPA. Single VPA treatment has no effect on RGC number.