Fig. 4

Cryopreserved periodontal ligament stem cell (cPDLSC) sheets retained the ability to differentiate into osteoblasts and adipocytes. Von Kossa staining showed no calcium nodules in non-induced cPDLSC sheets (a) and freshly prepared periodontal ligament stem cell (fPDLSC; e) sheets. Von Kossa staining showed similar calcium levels in cPDLSC (b) and fPDLSC (f) sheets. Oil Red O staining showed similar levels of lipid accumulation in non-induced cPDLSC sheets (c) and fPDLSC (g) sheets. Oil Red O staining showed similar levels of lipid accumulation in induced cPDLSC (d) and fPDLSC (h) sheets. i RT-PCR quantitation of runt-related transcription factor 2 (RUNX2), osterix (OSX), and osteocalcin (OCN) gene expression levels in PDLSCs derived from cryopreserved and freshly prepared cell sheets. j RT-PCR quantitation of peroxisome proliferating activated receptor γ (PPARγ2) and lipoprotein lipase (LPL) gene expression levels in PDLSCs derived from cryopreserved and freshly prepared cell sheets. Scale bars = 20 μm. Magnification: 40×. GAPDH glyceraldehyde 3-phosphate dehydrogenase, in induced, n non-induced