Ascorbic acid induces osteoblast differentiation of human suspension mononuclear cells.

BACKGROUND AIMS: Suspension mononuclear cells (MNCs) can be differentiated into osteoblasts with the induction of ascorbic acid and ß-glycerophosphate. The aim of this study was to determine the ability of suspension MNCs to differentiate into osteoblasts using ascorbic acid only. METHODS: Suspension MNCs were obtained by a combination of gradient centrifugation and culture selection. Suspension MNCs were subjected to differentiation assay by culturing them inside proliferation medium supplemented with 10 µg/mL, 30 µg/mL, 50 µg/mL, 60 µg/mL, 90 µg/mL and 500 µg/mL of ascorbic acid. Proliferation medium supplemented with 50 µg/mL ascorbic acid and 10 mmol/L ß-glycerophosphate was used as a positive control for osteoblast induction, and proliferation medium without ascorbic acid was used as a negative control. Differentiation analysis was performed using alkaline phosphatase (ALP) assay, von Kossa staining and expression of osteoblast-related genes. RESULTS: With all concentrations of ascorbic acid used, there was a significant increase (P < 0.05) in ALP-specific activity and mineralized nodule formation throughout the differentiation course compared with negative control. Ascorbic acid was also able to activate the expression of osteopontin (SPP1), osteonectin (SPARC) and runt-related transcription factor 2 (RUNX2) messenger RNA in positive control and ascorbic acid-induced MNCs (30 µg/mL and 90 µg/mL) but not in negative control. CONCLUSIONS: Ascorbic acid alone was sufficient to induce osteoblast differentiation from suspension MNCs; 30-90 µg/mL of ascorbic acid was found to be the optimal concentration. Ascorbic acid can be used as a nutritional supplement for cellular therapy of bone-related disease.

Differentiation of dental pulp stem cells into neuron-like cells in serum-free medium.

Dental pulp tissue contains dental pulp stem cells (DPSCs). Dental pulp cells (also known as dental pulp-derived mesenchymal stem cells) are capable of differentiating into multilineage cells including neuron-like cells. The aim of this study was to examine the capability of DPSCs to differentiate into neuron-like cells without using any reagents or growth factors. DPSCs were isolated from teeth extracted from 6- to 8-week-old mice and maintained in complete medium. The cells from the fourth passage were induced to differentiate by culturing in medium without serum or growth factors. RT-PCR molecular analysis showed characteristics of Cd146(+) , Cd166(+) , and Cd31(-) in DPSCs, indicating that these cells are mesenchymal stem cells rather than hematopoietic stem cells. After 5 days of neuronal differentiation, the cells showed neuron-like morphological changes and expressed MAP2 protein. The activation of Nestin was observed at low level prior to differentiation and increased after 5 days of culture in differentiation medium, whereas Tub3 was activated only after 5 days of neuronal differentiation. The proliferation of the differentiated cells decreased in comparison to that of the control cells. Dental pulp stem cells are induced to differentiate into neuron-like cells when cultured in serum- and growth factor-free medium.

In vitro chondrogenesis transformation study of mouse dental pulp stem cells.

A major challenge in the application of mesenchymal stem cells in cartilage reconstruction is that whether the cells are able to differentiate into fully mature chondrocytes before grafting. The aim of this study was to isolate mouse dental pulp stem cells (DPSC) and differentiate them into chondrocytes. For this investigation, morphological, molecular, and biochemical analyses for differentiated cells were used. To induce the chondrocyte differentiation, DPSC were cultured in chondrogenic medium (Zen-Bio, Inc.). Based on morphological analyses using toluidine blue staining, proteoglycan products appear in DPSC after 21 days of chondrocyte induction. Biochemical analyses in differentiated group showed that alkaline phosphatase activity was significantly increased at day 14 as compared to control (P < 0.05). Cell viability analyses during the differentiation to chondrocytes also showed that these cells were viable during differentiation. However, after the 14th day of differentiation, there was a significant decrease (P < 0.05) in the viability proportion among differentiated cells as compared to the control cells. In RT-PCR molecular analyses, mouse DPSC expressed Cd146 and Cd166 which indicated that these cells belong to mesenchymal stem cells. Coll I and Coll II markers showed high expression after 14 and 21 days, respectively. In conclusion, this study showed that DPSC successfully differentiated into chondrocytes.