The standard curve of graded concentrations of glucuronic acid has a correlation coefficient of 0.996 (a) and the changes in secreted GAG secreted into the medium were estimated (b). The values are expressed as the mean ± SD of three independent experiments, and significant differences between the values of the respective experimental groups and PDL-2 are indicated (*P<0.05). MSC-derived GAG was digested with streptomyces hyaluronidase (st.HAase), testicular hyaluronidase (te.HAase), or chondroitinase ABC (ChaseABC), and then stained with alcian blue (c). Two-dimensional electrophoresis of MSC-derived GAG was performed on cellulose acetate membrane. Purified hyaluronan (HA), dermatan sulfated (DS) and chondroitin sulfate (CS) were used as molecular markers, and the starting point for the first dimension is indicated by an asterisk (d).