Metabolite profiles of mesenchymal stem cells underwent death on 9.4 T MR spectroscopy

Abstract

Objective To explore the metabolite profiles of mesenchymal stem cells(MSCs) underwent death using 9.4 T high resolution MR spectroscopy. Methods MSCs were cultured and treated for 6, 12 and 24 hours in a stimulated condition which included hypoxia, serum deprivation and changes of microenvironment. Cell death and the mortality was detected by light microscopy, Hoechst staining and flow cytometry analyses. The morality of stem cells was analyzed using one-way analysis of variance (ANOVA). Cell metabolite extraction was prepared by methanol-chloroform(M/C) method and analyzed on a 9.4 T MR device. 1H-MR spectroscopy was obtained and the metabolite concentration of each time point was calculated and compared using one way ANOVA, the difference between two groups was analyzed by SNK test. Results Necrosis was the major form of cell death in the built model. The morality of every time sets was 16±4(0 h), 658±61(6 h), 1 571±154(12 h) and 2 816±178(24 h) respectively, and the difference between each groups were statistically significant (F=298.96, P<0.01). After induced stem cells death for 6, 12 and 24 h, the metabolite concentrations at 0.89 ppm was (1.48±0.69), (2.32±0.63) and (2.15±0.45) nmol/mg respectively, and increased compared to the control[(1.41 ± 0.25)nmol/mg]with statistical significance (F= 329.57, P<0.01). The metabolite concentrations at 1.28 ppm was (6.42±0.31), (7.26±0.32) and (7.01± 0.61) nmol/mg, respectively, and increased compared to the control[(5.76 ± 0.74)nmol/mg]with statistical significance (F=19.56, P<0.01).The metabolite concentrations at 1.60 ppm was (2.36±0.31), (2.29±0.16) and (2.31 ± 0.24) nmol/mg respectively, and increased compared to the control[(1.96 ±0.27)nmol/mg]with statistical significance (F=4.35, P<0.05). After induced stem cells death for 12 hours, the metabolite concentrations at 0.89 ppm was increased compared to 6 hours with statistical significance (P<0.05). The metabolite concentrations at 1.28 ppm was increased compared to 6 hours with statistical significance (P< 0.05). After induced stem cells death for 24 hours, the metabolite concentrations at 0.89 ppm was decreased compared to 12 hours with statistical significance (P<0.05). Conclusions There are some specific characteristics on MRS of MSCs underwent death, and the fatty acid peak may serve as a biomarker for cell death. Key words: Mesenchymal stem cells; Magnetic resonance spectroscopy; Metabolism