Bone marrow mesenchymal stem cells improve cognitive impairments induced by methamphetamine in rats and reduce relapse.

Introduction: Chronic exposure to methamphetamine (Meth) results in permanent central nervous system damage and learning and memory dysfunction. This study aimed at investigating the therapeutic effects of bone marrow mesenchymal stem cells (BMMSCs) on cognitive impairments in Meth addicted rats and comparing intravenous (IV) delivery with intranasal (IN) delivery of BMMSCs. Methods: Adult Wistar rats were randomly divided into 6 groups; Control; Meth-addicted; IV-BMMSC (Meth administered and received IV BMMSCs); IN-BMMSC (Meth administered and received IN BMMSCs); IV-PBS (Meth administered and received IV Phosphate-buffered saline (PBS); IN-PBS (Meth administered and received IN PBS). BMMSCs were isolated, expanded in vitro, immunophenotyped, labeled, and administered to BMMSCs-treated groups (2 × 10⁶ cells). The therapeutic effect of BMMSCs was measured using Morris water maze and Shuttle Box. Moreover, relapse-reduction was evaluated by conditioning place preference after 2 weeks following BMMSCs administration. The expression of brain-derived neurotrophic factor (BDNF) and glial-derived neurotrophic factor (GDNF) in rat hippocampus was assessed using immunohistochemistry method. Results: Administration of BMMSCs caused a significant improvement in the learning and memory functions of Meth-addicted rats and reduced the relapse (P<0.01). In behavioral tests, comparison of IV and IN BMMSC-treated groups did not show any significant difference. Administration of BMMSCs improved the protein level of BDNF and GDNF in the hippocampus, as well as causing behavioral improvement (P<0.001). Conclusion: BMMSC administration might be a helpful and feasible method to treat Meth-induced brain injuries in rats and to reduce relapse. BMMSCs were significantly higher in IV-treated group compared to the IN route. Moreover, the expression of BDNF and GDNF was higher in IN-treated rats compared with IV treated group.