Objective: Our research attempted to show that mouse dental pulp stem cells (DPSCs) with characters such as accessibility, propagation and higher proliferation rate can provide an improved approach for generate bone tissues. With the aim of finding and comparing the differentiation ability of mesenchymal stem cells derived from DPSCs into osteoblast and osteoclast cells; morphological, molecular and biochemical analyses were conducted.Materials and Methods: In this experimental study, osteoblast and osteoclast differentiation was induced by specific differentiation medium. In order to induce osteoblast differentiation, 50 mg mL-1 ascorbic acid and 10 mM b-glycerophosphate as growth factors were added to the complete medium consisting alpha-modified Eagle’s medium (a-MEM), 15% fetal bovine serum (FBS) and penicillin/streptomycin, while in order to induce the osteoclast differentiation, 10 ng/mL receptor activator of nuclear factor kappa-B ligand (RANKL) and 5 ng/mL macrophage-colony stimulating factor (M-CSF) were added to complete medium. Statistical comparison between the osteoblast and osteoclast differentiated groups and control were carried out using t test.Results: Proliferation activity of cells was estimated by 3- [4, 5-dimethylthiazol-2-yl] -2, 5 diphenyl tetrazolium bromide (MTT) assay. Statistical results demonstrated significant difference (p<0.05) between the control and osteoblastic induction group, whereas osteoclast cells maintained its proliferation rate (p>0.05). Morphological characterization of osteoblast and osteoclast was evaluated using von Kossa staining and May-Grunwald-Giemsa technique, respectively. Reverse transcription-polymerase chain reaction (RT-PCR) molecular analysis demonstrated that mouse DPSCs expressed Cd146 and Cd166 markers, but did not express Cd31, indicating that these cells belong to mesenchymal stem cells. Osteoblast cells with positive osteopontin (Opn) marker were found after 21 days, whereas this marker was negative for DPSCs. CatK, as an osteoclast marker, was negative in both osteoclast differentiation medium and control group. Biochemical analyses in osteoblast differentiated groups showed alkaline phosphatase (ALP) activity significantly increased on day 21 as compared to control (p<0.05). In osteoclast differentiated groups, tartrate-resistant acid phosphatase (TRAP) activity representing osteoclast biomarker didn’t show statistically significant as compared to control (p>0.05).Conclusion: DPSCs have the ability to differentiate into osteoblast, but not into osteoclast cells.

Dear Editor: An 18-month-old girl with failure to thrive, frontal bossing, bilateral proptosis, profound hepatosplenomegaly, severe anemia and thrombocytopenia was admitted to our pediatric oncology department. On physical examination she was a fussy baby with malformed teeth and abdominal distension. There was complete visual loss in the child...

Bone fracture is among the clinical complications that impose huge financial burdens on the society. To date, many factors have been cited as being effective in accelerating bone healing. Among these factors are electromagnetic fields (EMF). Osteoblasts and OSTEOCLASTS play a central role in ossification process. This case-control clinical trial was conducted to compare the effect of EMF on the relative number of these cells in the process of bone healing.Two groups of mature rats were chosen and their femur bones were broken. The case group was exposed to 0.25 mT electromagnetic field 4 hours daily. Broken bones were sampled on the day of breaking the femur bones, and 3, 6, 9, 12 and 15 days after the first exposure to EMF. The samples were studied under light microscope (LM) after tissue processing, sectioning and H & E staining. The osteoblasts and OSTEOCLASTS were counted in every microscopic field.The results showed a significant rise in the number of osteoblasts in the case group (exposed to EMF), compared to the control group. This study concludes that exposure to EMF, leads to an increase in the number of osteoblasts and likely contributes to faster bone healing.