Differentiation of human dental pulp stem cells into neuronal by resveratrol.

Dental pulp stem cells (DPSCs) have been proposed as a promising source of stem cells in nerve regeneration due to their close embryonic origin and ease of harvest. Resveratrol (RSV) is a natural polyphenolic and possesses many biological functions such as anti-inflammatory activity and protection against atherosclerosis and neuroprotective activities. There is increasing evidence showing that RSV plays a pivotal role in neuron protection and neuronal differentiation. In this study, we isolated DPSCs from impacted third molars and investigated whether RSV induces neuronal differentiation of DPSCs. To avoid loss of DPSCs multipotency, all the experiments were conducted on cells at early passages. RT-PCR results showed that RSV-treated DPSCs (RSV-DPSCs) significantly increased the expression of the neuroprogenitor marker Nestin. When RSV-DPSCs were differentiated with neuronal induction media (RSV-dDPSCs), they showed a cell morphology similar to neurons. The expression of neuronal-specific marker genes Nestin, Musashi, and NF-M in RSV-dDPSCs was significantly increased. Immunocytochemical staining and Western blot analysis showed that the expression of neuronal marker proteins, Nestin, and NF-M, was significantly increased in RSV-dDPSCs. Therefore, we have shown that RSV treatment, along with the use of neuronal induction media, effectively promotes neuronal cell differentiation of DPSCs.

Exosomes derived from human dental pulp stem cells increase flap survival with ischemia-reperfusion injuries.

Aim: To investigate the effect of hDPSC-Exos in flap I/R injury, a condition in which tissue damage increases after blood flow is restored to the flap after ischemia. Materials & methods: HUVECs were used to investigate the influences and mechanisms of hDPSC-Exos on cell proliferation and migration. A rat model was established to verify the role of hDPSC-Exos in flap I/R injuries in vivo. Results: hDPSC-Exos promoted the proliferation, migration and tube formation of HUVECs in a dose-dependent way by activating PI3K/AKT signaling pathway, and improved the survival and microvessel density of the flap and suppressed epithelial cell apoptosis. Conclusion: hDPSC-Exos can enhance flap repair after I/R injury. This process may be mediated by the activation of PI3K/AKT signaling pathway.

Skin flap transplantation is one of the most important methods of repairing refractory wounds and organ reconstruction. I/R injury and insufficiency of neovascularization significantly affect the survival of flaps. Human dental pulp stem cells (hDPSCs) are a type of mesenchymal stem cells (MSCs) present in dental pulp tissue that have attracted increasing attention. They can play a repair role in a variety of ischemic injuries and neovascularization. Exosomes are important paracrine mediators between MSCs and target cells, containing a variety of proteins, mRNA and miRNA. Recent studies have shown that some exosomes derived from MSCs can improve I/R injury, promote angiogenesis and inhibit apoptosis. This study confirmed that hDPSC-Exos could promote the proliferation, migration and tubule formation of vein endothelial cells in a dose-dependent manner. Inhibition of PI3K/AKT signaling pathway can reduce the above promoting effects, suggesting that these processes may depend on the activation of PI3K/AKT signaling pathway. In the rat model, hDPSC-Exos can significantly improve the survival rate and microvessel density of flaps, and inhibit epithelial cell apoptosis.

Effects of cold atmospheric plasma treatment on resin bonding to high-translucency zirconia ceramics.

This study aims to evaluate the effects of cold atmospheric plasma (CAP) treatment on the bonding of resin cement to high-translucency zirconia. Zirconia specimens were subjected to different treatments: no treatment (ZrT), 10-methacryloyloxydecyl dihydrogen phosphate (MDP)-containing primer (ZrT-M), alumina particle air-abrasion with/without MDP-containing primer (ZrT-AM/ZrT-A), CAP with/without MDP-containing primer (ZrT-PM/ZrT-P). The surface topography, wettability, and chemical composition were evaluated. The shear bond strength (SBS) was tested before and after thermocycling. CAP did not alter the morphology, increased the wettability, and decreased the carbon/oxygen ratio of zirconia surface. The SBSs of ZrT-PM and ZrT-P were significantly higher than the other groups. After thermocycling, ZrT-A, ZrT-M, ZrT-AM, and ZrT-P showed comparable SBSs, all of which were lower than ZrT-PM. It was concluded that CAP improved the bonding performance of high-translucency zirconia without damaging its surface. The combination of CAP with MDP further enhanced the bond strength and may enable durable bonding.

Lentiviral­mediated Shh reverses the adverse effects of high glucose on osteoblast function and promotes bone formation via Sonic hedgehog signaling.

Patients with diabetes tend to have an increased incidence of osteoporosis, which may be associated with hyperglycemia; however, the pathogenic mechanisms governing this interaction remain unknown. The present study sought to investigate whether elevated extracellular glucose levels of bone mesenchymal stem cells (BMSCs) could influence osteoblastic differentiation and whether the intracellular Sonic hedgehog (Shh) pathway could adjust the effects. Furthermore, to verify the results in vivo, a rat tooth extraction model was constructed. BMSCs were incubated in eight types of culture medium, including low glucose (LG), LG + lentivirus (Lenti), LG + Lenti­small interfering RNA (Lenti­siRNA), LG + Lenti­Shh, high glucose (HG), HG + Lenti, HG + Lenti­siRNA and HG + Lenti­Shh. The lentiviral transfection efficiency was observed using a fluorescence microscope; protein and mRNA expression was detected by western blotting and reverse transcription­quantitative polymerase chain reaction (RT­qPCR). The matrix mineralization and alkaline phosphatase (ALP) activity of BMSCs were examined by Alizarin red staining and ALP activity assays, respectively. The expression of osteogenesis­related genes in BMSCs were quantified by RT­qPCR. The alveolar ridge reduction was measured and histological sections were used to evaluate new bone formation in the tooth socket. With high concentrations of glucose, Shh expression, matrix mineralization nodules formation, ALP activity and the levels of bone morphogenic protein 4 (BMP4), bone sialoprotein (BSP) and osteopontin (OPN) expression were greatly reduced compared with LG and corresponding control groups. Whereas activated Shh signaling via Lenti­Shh could increase the number of matrix mineralization nodules, ALP activity, and the expression levels of BMP4, BSP and OPN in BMSCs. Additionally, in vivo assays demonstrated that Lenti­Shh induced additional bone formation. Collectively, the results of the present study indicated that HG inhibited the Shh pathway in osteoblasts and resulted in patterning defects during osteoblastic differentiation and bone formation, while the activation of Shh signaling could suppress these deleterious effects.

Enhanced Biological Behavior of In Vitro Human Gingival Fibroblasts on Cold Plasma-Treated Zirconia.

OBJECTIVE: To evaluate whether atmospheric-pressure dielectric-barrier-discharge plasma treatment of zirconia enhances its biocompatibility with human gingival fibroblasts. MATERIALS AND METHODS: The zirconia disks were divided into four groups and treated using helium atmospheric-pressure dielectric-barrier-discharge plasmas for 30, 60 or 90 s or left untreated. The surface morphology, wettability and chemical elements were analyzed. Fibroblasts density, morphology, morphometry and attachment-related genes expression were measured at different time points from 3 to 72 h. RESULTS: After plasma treatment, the surface morphology and roughness remained the same, while the contact angle decreased from 78.31° to 43.71°, and the surface C/O ratio decreased from 3.17 to 0.89. The surficial areas and perimeters of HGFs were increased two-fold in the treated groups at 3 h. Fibroblasts density increased on treated disks at all time points, especially the ones treated for 60 s. Attachment-related genes in the groups treated for 30 and 60 s were significantly higher at 3 and 24 h. CONCLUSION: The helium atmospheric-pressure dielectric-barrier-discharge plasma treatment enhances the biological behavior of fibroblasts on zirconia by increasing the expression of attachment-related genes within 24 h and promoting the cell density during longer culture times. Wettability of zirconia, an important physicochemical property, has a vital influence on the cell behaviors.

[Coverage errors of five shade guide systems to vital natural teeth].

OBJECTIVE: To compare the coverage errors (CE) of five different shade guides in anterio vital natural teeth of selected people. METHODS: Anterior vital natural teeth were measured with Crystaleye spectrophotometer, color coordinates of the teeth and five shade guides A (VITA Classical), B (VITA 3D-Master), C (Chromascop), D (Shofu Vintage Halo NCC) and E (Noritake)were analyzed with the supporting software. The CE of the five shade guide systems to natural teeth were evaluated in cervical, body and incisal regions, and difference in CE among shade guides was determined. RESULTS: In the cervical region, shade guide A had the maximal CE value (3.09 ± 0.97) and shade guide D had the minimal CE value (1.62 ± 0.75).In the body region, CE of shade guide B (1.65 ± 0.64) and shade guide D (1.52 ± 0.74) were lower than those of shade guides A (2.04 ± 0.80), C (2.04 ± 0.90) and E (2.02 ± 0.84) (P < 0.05).In the incisal part, all CE were below 2.00, and again shade guide A had the maximal CE value (1.81 ± 0.86) and shade guide D had the minimal CE value (1.28 ± 0.55). CONCLUSIONS: Within the limitation of the study, shade guide D had better color coverage of natural teeth in cervical, body and incisal regions.