Ganagliflozin proline attenuates osteogenic dysfunction and inflammatory signaling during exposure to advanced glycation end products in murine osteoblasts

Figure 1 Advanced glycation end product levels under normal- and high-glucose culture conditions in MC3T3-E1 cells. A: Conceptual schematic showing biochemical routes by which a high-glucose environment may favor advanced glycation end product (AGE) formation and type I collagen modification. Schiff bases, Amadori products, methylglyoxal, glyoxal, and 3-deoxyglucosone may modify collagen residues and generate AGE adducts or crosslinks. This panel presents conceptual background; specific collagen adducts and crosslinks were not measured in this study; B: AGE levels in culture supernatants from MC3T3-E1 cells cultured under normal-glucose (NG) (5.5 mmol/L) or high-glucose (HG) (25 mmol/L) conditions for 3 days, 7 days, or 14 days, measured by enzyme-linked immunosorbent assay; C: AGE levels in cell lysates under the corresponding conditions; D-F: Comparison of AGE levels between culture supernatants and cell lysates on days 3, 7, and 14, respectively; G: Time-course changes in AGE levels in NG supernatants, NG lysates, HG supernatants, and HG lysates. Cultures containing 25 mmol/L glucose showed higher measured AGE levels than cultures containing 5.5 mmol/L glucose. Because no mannitol or L-glucose osmotic control was included, these differences cannot be attributed specifically to glucose metabolism, and an osmotic contribution cannot be excluded. Data are presented as the mean ± SD from three independent biological experiments (n = 3). Two-group comparisons were performed using two-tailed Welch’s t test. Time-course data were analyzed using two-way analysis of variance followed by multiple-comparison adjustment. Non-significant comparisons are not labeled. ^aP < 0.05. ^bP < 0.01. ^cP < 0.001. ^dP < 0.0001. NS: Non-significant; AGE: Advanced glycation end product; MGO: Methylglyoxal; 3-DG: 3-Deoxyglucosone; GO: Glyoxal; FL: Fructosyllysine; CML: Nε-(carboxymethyl)lysine; CEL: Nε-(carboxyethyl)lysine; G-H1: Glyoxal-derived hydroimidazolone-1; 3-DG-H1: 3-Deoxyglucosone-derived hydroimidazolone-1; MG-H1: Methylglyoxal-derived hydroimidazolone-1; NG: Normal-glucose; HG: High-glucose.