Glyphosate-based herbicide induces toxic effects on human adipose-derived mesenchymal stem cells grown in human plasma

Glyphosate (N-phosphonometil-glicine)-based formulations are herbicides widely used in world agriculture as well as in Brazilian territory. Therefore, it is essential to investigate the possible consequences of glyphosate exposure in human health. The effects of a glyphosate formulation (GLY-R) were assessed using human adipose-derived mesenchymal stem cells (hASCs), which possess multilineage differentiation potential, in an undifferentiated state and during differentiation of the cells. hASCs were exposed to a mixture containing basal or differentiation medium and GLY-R at a concentration of 36 μg mL−1 during short (24, 48, and 72 h) and long (up to 21 days) exposure times. Cytotoxicity of glyphosate formulation was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay and we found that GLY-R IC50 (half maximum inhibitory concentration) was 42.98 (± 1.72) μg mL−1. Annexin V-Alexa Fluor 488 and propidium iodide staining using fluorescence microscopy suggested that exposure of hASCs to GLY-R induced death by apoptosis and necrosis after 24 h. Morphological changes were observed by light microscopy during the hASC differentiation in the presence of the herbicide. In addition, 5-bromo 4-chloro 3-indolyl phosphate p-toluidine (BCIP)-nitroblue hydrochloric tetrazolium (NBT) assay showed that alkaline phosphatase activity was lower in cells induced to osteogenic differentiation with GLY-R formulation. Expressions of genes associated to adipogenic and osteogenic differentiation were also compared to the control after herbicide exposure for 21 days. Our results suggest that GLY-R induced toxic effects on adult stem cells derived from adipose tissue.