Fig. 1. The effects of dioxin on the various functions of stem cells in vitro.

The inhibition of cell viability by dioxin treatment for 72 h was determined via an MTT assay in both stem cells and fibroblasts. The cell viability (%) was calculated as the percent of the vehicle control (a). Schematic representation described the experimental protocol for differentiation and treatment. Confluent stem cells were cultured for 21 days in osteogenic or adipogenic medium with or without dioxin (10 nM). The effect of dioxin on osteoblast or adipocyte differentiation was determined by alizarin red or oil red O staining, respectively. Relative quantification of calcium mineral content or lipid droplet formation was determined by absorbance measurements at 570 nm or 500 nm, respectively (b). The effect of dioxin on the MSC migration ability was evaluated using a transwell migration assay. Dioxin treatment significantly decreased MSC migration across the membrane compared with the negative controls (c). The results are presented as the mean ± SD from at least three independent experiments