Fig. 3

Magnesium deficiency activated Wnt/β-catenin signaling in chondrocytes. Mouse chondrocytes were cultured under different magnesium conditions (0.7 mM, 0.4 mM and 0.1 mM). Protein levels of β-catenin in total cell lysates (A, B) and nuclear fractions (C, D) were detected by western blot. The quantitation of protein expression of β-catenin was done by densitometry analysis of the protein bands. Values were normalized to β-tubulin and TATA-binding protein (TBP), respectively (n = 8 for β-catenin in total cell lysates; n = 4 for nuclear β-catenin). E mRNA levels of Catenin, Wnt3a, Wnt5a, Wnt5b, and Wnt16 were investigated by qRT-PCR (n = 3, 4 or 5). β-actin was used as housekeeping gene. F, G Immunostaining and quantitative analysis of cells positive for β-catenin in sham and DMM-induced OA mice fed with diets containing different amounts of magnesium (500 mg/kg, 300 mg/kg, 100 mg/kg) (n = 9). Scale bar: 100 μm. Data were expressed as the mean ± SD and analyzed by one-way ANOVA test. (*P< 0.05, **P< 0.01, ***P< 0.001, ****P< 0.0001)