Effect of Tribulus terrestris saponins on proliferation of adipose-derived mesenchymal stem cells.

Adipose-derived mesenchymal stem cells (ASCs) transplantation has shown great promise for treating various diseases; however, poor viability of transplanted ASCs because of oxidative stress has limited its therapeutic efficiency. Plant saponins are recently been reported to have antioxidant activity tested in various cancer cell lines. This study was designed to investigate the protective effects of Tribulus terrestris saponins (TTS) on the proliferation of ASCs. The cytotoxic activity of hydrogen peroxide (H₂ O₂ ) was determined by treating ASCs with 100, 200, 300, 400, and 500 µM H₂ O₂ for 2 hours. ASCs were treated with 6.25, 12.5, 25, 50, and 100 µg/mL concentrations of TTS for the proliferative experiment. To check the protective effect of TTS, experiments were designed in two ways. In one set, ASCs were pretreated with different concentrations of TTS for 2 hours and then apoptosis was induced by treating them with 400 µM H₂ O₂ for next 2 hours, while in other set, ASCs were first treated with 400 µM H₂ O₂ for 2 hours and subsequently with different concentrations of TTS for 24 hours. The vitality and proliferation potential of cells were detected by 3-(4,5-Dimethylthiazol-2-Yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The result of the current study shows that in response to stress-induced by H₂ O₂ at concentration of 400 µM, ASCs underwent growth arrest and cell viability was reduced to half while treatment with TTS before and after H₂ O₂ exposure significantly prevents premature apoptosis. The findings suggest that saponins may act as an effective protective agent against oxidative stress-induced ASCs apoptosis.