Fig. 5
Decreased osteogenic capacity of PDLSCs by inhibiting NO production could be rescued by activating the JNK/MAPK pathway. a Alkaline phosphatase (ALP) staining showing that l-NG-monomethyl arginine (l-NMMA) treatment downregulated the level of ALP, while activating the JNK/MAPK signaling pathway rescued its expression. b Alizarin Red staining showing that l-NMMA significantly reduced mineralization, and this effect was reversed by activating JNK/MAPK. Data are representative of three independent experiments. **P < 0.01. c Activating the JNK/MAPK signaling pathway restored calcium levels downregulated by l-NMMA. **P < 0.01. d Real-time RT-PCR showing that l-NMMA treatment significantly reduced runt-related transcription factor 2 (Runx2), osterix (OSX), and osteopontin (OPN) mRNA expression levels, while activating the JNK/MAPK pathway largely eliminated the downregulation of osteogenic markers caused by l-NMMA. All experiments are representative of three replicates. **P < 0.01. e Western blot showing that l-NMMA downregulated the expression of ALP, Runx2, and phosphorylated c-Jun N-terminal kinase (p-JNK), while JNK activator largely restored expression of these markers. f,g Real time RT-PCR and Western blot analysis of adipogenic marker expression during osteogenic differentiation. The peroxisome proliferator-activated receptor (PPAR)γ level was significantly reduced by sodium nitroprusside (SNP), while SP600125 partially eliminated this effect. Blocking NO generation with l-NMMA led to significant upregulation of PPARγ, and anisomycin crippled this influence. All experiments are representative of three replicates. **P < 0.01