Pretreatment with Tetrandrine Enhanced the Antioxidative and Immunomodulatory Activities of Mesenchymal Stem Cells

Abstract In this study, mesenchymal stem cells (MSCs) were pretreated with Tetrandrine (TET) as a bis-benzyl-isoquinoline alkaloid with anti-inflammatory and immunomodulatory effects to examine the effects of this molecule on the antioxidative potential of MSCs and their modulatory effects on activated peripheral blood mononuclear cells (PBMCs). After treatment of MSCs with TET, the viability of MSCs was detected using MTT assay and Trypan blue staining. Flow cytometry technique was applied to evaluate cell cycle distribution and immunophenotype of MSCs. The production of superoxide dismutase 3 (SOD3), malondialdehyde (MDA), kynurenine, TGF-β, and IFN-γ were measured by spectrophotometry. Then, TET-pretreated MSCs were cocultured with PBMCs. The MTT assay was used to measure the proliferation of PBMCs. Cell cycle progression of PBMCs and frequency of regulatory T cells were evaluated using Flow cytometry. ELISA assay was also applied to determine the concentrations of TGF-β and IFN-γ after coculturing. According to our data, TET enhanced the secretion of SOD3 and kynurenine from MSCs, while the production of IFN-γ was reduced. No change was observed in the viability, proliferation, and immunophenotype of MSCs after treatment with TET. Moreover, the proliferation and frequency of PBMCs in the S and G2/M phases of cell cycle reduced after co-culturing with TET-pretreated MSCs. The concentration of TGF-β was increased in the supernatant of PBMCs, but the level of IFN-γ was reduced. Our data suggested the pretreatment of MSCs with TET as a novel strategy for increasing the antioxidative and immunomodulatory activity of these cells.