Dose-dependent effects of tetramethylpyrazine on the characteristics of human umbilical cord mesenchymal stem cells for stroke therapy

Umbilical cord mesenchymal stem cells (ucMSCs) may serve as a new source for cell therapy in stroke patients; however, the poor efficiency of viability, migration, and differentiation limit the application of ucMSCs. This study determined the dose-dependent effects of tetramethylpyrazine (TMP) on the characteristics of ucMSCs in vitro. The effect on proliferation was determined with Cell Counting kit-8 assays. Cell migration was analyzed with Transwell assays and western blot analysis. Differentiation of ucMSCs was evaluated according to markers and the expression of relevant proteins and genes. Secretion capacity was detected by ELISA analysis. TMP protected ucMSCs against H₂O₂ induced-oxidative damage but had no influence on ucMSC activity at a low concentration. Furthermore, ucMSC migration was improved by TMP via the SDF-1/CXCR4 axis. The observed effects were dose dependent. At a high dose, however, TMP induced the differentiation of ucMSCs into neuron-like cells that expressed neuron-specific markers. In addition, the secretion of cytokines was significantly increased by TMP. Therefore, TMP pre-treatment of ucMSCs may be an effective strategy to enhance the efficiency of ucMSC transplantation in stroke therapy.