Effect of tetraethylammonium and B vitamins group on the efficacy of cell replacement therapy in the treatment of Parkinson\'s disease in the 6-hydroxydopamine animal model

Introduction: Transplantation of embryonic ventral mesencephalic (VM) dopamine neurons into the striatum is a currently explored therapeutic strategy for treatment of patients with patients with Parkinson's disease (PD). However, this strategy has been limited with poor cell survival, generally ranging from 5-20%. In this study, we investigated the effect of potassium channel blocker of tetraethylammonium (TEA) and B vitamins supplementation on the efficacy of cell replacement therapy in the treatment of 6-hydroxydopamine (6-OHDA)-induced Parkinsonism. Methods: Cell suspension was prepared from embryonic day 14 (E14) VM of rat fetuses and was transplanted into striatum of Parkinsonian rats after overnight hibernation with TEA or B vitamins. The Parkinsonian rats were also treated with TEA or B vitamins for two weeks after transplantation. Severity of Parkinsonism was assessed by apomorphine-induced rotational test in several steps before and after transplantation. Results: 1- Transplantation of VM cell suspension significantly decreased behavioral symptoms of Parkinsonism in the apomorphine-induced rotational test. 2-TEA treatment further decreased these symptoms. 3- B vitamins treatment had no additional effect in amelioration of the symptoms. 4-Treatment with both TEA and B vitamins also further decreased behavioral symptoms, which in one post-transplantation test was even more than the effect of TEA alone. Conclusion: TEA, especially in combination with B vitamins supplementation, can increase the efficacy of cell replacement therapy in the 6-OHDA rat PD model.