Cytidine 5′-diphosphocholine (CDP-choline) adversely effects on pilocarpine seizure-induced hippocampal neuronal death

Abstract Citicoline (CDP-choline; cytidine 5′-diphosphocholine) is an important intermediate in the biosynthesis of cell membrane phospholipids. Citicoline serves as a choline donor in the biosynthetic pathways of acetylcholine and neuronal membrane phospholipids, mainly phosphatidylcholine. The ability of citicoline to reverse neuronal injury has been tested in animal models of cerebral ischemia and clinical trials have been performed in stroke patients. However, no studies have examined the effect of citicoline on seizure-induced neuronal death. To clarify the potential therapeutic effects of citicoline on seizure-induced neuronal death, we used an animal model of pilocarpine-induced epilepsy. Temporal lobe epilepsy (TLE) was induced by intraperitoneal injection of pilocarpine (25 mg/kg) in adult male rats. Citicoline (100 or 300 mg/kg) was injected into the intraperitoneal space two hours after seizure onset and a second injection was performed 24 h after the seizure. Citicoline was injected once per day for one week after pilocarpine- or kainate-induced seizure. Neuronal injury and microglial activation were evaluated at 1 week post-seizure. Surprisingly, rather than offering protection, citicoline treatment actually enhanced seizure-induced neuronal death and microglial activation in the hippocampus compared to vehicle treated controls. Citicoline administration after seizure-induction increased immunoglobulin leakage via BBB disruption in the hippocampus compared with the vehicle-only group. To clarify if this adverse effect of citicoline is generalizable across alternative seizure models, we induced seizure by kainate injection (10 mg/kg, i.p.) and then injected citicoline as in pilocarpine-induced seizure. We found that citicoline did not modulate kainate seizure-induced neuronal death, BBB disruption or microglial activation. These results suggest that citicoline may not have neuroprotective effects after seizure and that clinical application of citicoline after seizure needs careful consideration.