ABSTRACT
A glass belonging to the system SiO2-P2O5-CaO-MgO-Na2O-K2O was modified by introducing two different amounts of manganese oxide (MnO). Mn-doped glasses were prepared by melt and quenching technique and characterized by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) observation and energy dispersion spectrometry (EDS) analysis. In vitro bioactivity test in simulated body fluid (SBF) showed a slight decrease in the reactivity kinetics of Mn-doped glasses compared to the glass used as control; however the glasses maintained a good degree of bioactivity. Mn-leaching test in SBF and minimum essential medium (MEM) revealed fluctuating trends probably due to a re-precipitation of Mn compounds during the bioactivity process. Cellular tests showed that all the Mn-doped glasses, up to a concentration of 50 µg/cm(2) (µg of glass powders/cm(2) of cell monolayer), did not produce cytotoxic effects on human MG-63 osteoblasts cultured for up to 5 days. Finally, biocompatibility tests demonstrated a good osteoblast proliferation and spreading on Mn-doped glasses and most of all that the Mn-doping can promote the expression of alkaline phosphatase (ALP) and some bone morphogenetic proteins (BMPs).
Subject(s)
Bone Regeneration/drug effects , Glass/chemistry , Manganese/pharmacology , Cell Line , Cell Proliferation/drug effects , Crystallization , Differential Thermal Analysis , Gene Expression Regulation/drug effects , Humans , Hydrogen-Ion Concentration , L-Lactate Dehydrogenase/metabolism , Malondialdehyde/metabolism , Osteoblasts/cytology , Osteoblasts/drug effects , Osteoblasts/ultrastructure , Powders , Spectrometry, X-Ray Emission , Transition Temperature , X-Ray DiffractionABSTRACT
A 3D-glass-ceramic scaffold for bone tissue engineering with an interconnected macroporous network of pores was doped with silver ions in order to confer antibacterial properties. For this purpose, silver ions were selectively added to the scaffold surfaces through ion-exchange using an aqueous silver nitrate solution. The silver-doped scaffolds were characterized by means of leaching, in vitro antibacterial, and citotoxicity tests. In particular, the silver effect was examined through a broth dilution test in order to evaluate the proliferation of bacteria by counting the colonies forming units. Moreover, cytotoxicity tests were carried out to understand the effect of silver-containing scaffolds on cell adhesion, proliferation, and vitality. For all tests a comparison between silver-doped scaffold and silver-doped scaffold dry sterilized was performed.
Subject(s)
Anti-Infective Agents, Local/pharmacology , Biocompatible Materials/pharmacology , Bone Transplantation/methods , Ceramics/chemistry , Glass/chemistry , Silver Nitrate/pharmacology , Tissue Scaffolds , Anti-Infective Agents, Local/analysis , Cell Adhesion/drug effects , Cell Survival/drug effects , Coated Materials, Biocompatible/pharmacology , Ion Exchange , Materials Testing/methods , Microscopy, Electron, Scanning/methods , Silver/pharmacology , Silver Nitrate/analysis , Staphylococcus aureus/drug effects , Surface Properties , Tissue Engineering/methods , X-Ray Diffraction/methodsABSTRACT
BACKGROUND: Bone replacement is frequently needed in periodontal, orthopedic, and maxillofacial diseases. To avoid complications with autografts and allografts, artificial grafts (scaffolds) are candidates for stimulating bone regeneration after colonization with osteoblasts. Moreover, osteoblast activity can be induced by biological or physical stimulation. In this research, extracorporeal shock waves were used to improve the ability of human osteoblasts to colonize scaffolds and to induce their osteogenic properties. METHODS: Osteoblasts, treated with shock waves, were seeded on glass-ceramic macroporous scaffolds. Cells in scaffolds were counted after detachment and examined for calcium nodule formation (Alizarin staining), for differentiation markers (real time polymerase chain reaction), and for scaffold colonization (scanning electron microscope). RESULTS: Shock waves initially increased both the number and the activity of osteoblasts in the scaffold, but subsequently increased only osteoblast activity. Moreover, shock waves favored scaffold colonization even in the deeper layers. CONCLUSIONS: The calcium deposits and differentiation markers studied have demonstrated that shock waves increase osteoblast migration and penetration into scaffolds. CLINICAL RELEVANCE: This study may provide an important starting point for the introduction of shock waves to boost bone formation through osteoblast stimulation in diseases characterized by bone defects.
Subject(s)
High-Energy Shock Waves , Osteoblasts/physiology , Tissue Scaffolds , Analysis of Variance , Bone Regeneration/physiology , Cell Line , Ceramics/chemistry , Glass/chemistry , Humans , Materials Testing , Microscopy, Electron, Scanning , Polyurethanes/chemistry , Porosity , Reverse Transcriptase Polymerase Chain ReactionABSTRACT
Conjugated linoleic acid (CLA) is reported to have anti-cancer activity, based on animal and in vitro studies. Since it has been suggested that CLA anti-carcinogenic effect stems from its anti-inflammatory properties, this study investigated whether CLA can prevent cell proliferation induced by TPA in human keratinocytes NCTC 2544 contemporary to inhibition of inflammation. Results obtained showed that CLA prevents increased cell proliferation and production of pro-inflammatory molecules determined by TPA, being this effect due to modulation of PPARs and NFkB activity. The involvement of PPARalpha in CLA effect was demonstrated by adding to the cells an antagonist of PPARalpha.
Subject(s)
Cytokines/biosynthesis , Keratinocytes/drug effects , Linoleic Acids, Conjugated/pharmacology , Tetradecanoylphorbol Acetate/toxicity , Cell Proliferation/drug effects , Cells, Cultured , DNA/metabolism , Humans , NF-kappa B/metabolism , PPAR alpha/antagonists & inhibitors , PPAR alpha/physiology , PPAR-beta/physiologyABSTRACT
BACKGROUND AND OBJECTIVE: Laser therapy is a new approach applicable in different medical fields when bone loss occurs, including orthopedics and dentistry. It has also been used to induce soft-tissue healing, for pain relief, bone, and nerve regeneration. With regard to bone synthesis, laser exposure has been shown to increase osteoblast activity and decrease osteoclast number, by inducing alkaline phosphatase (ALP), osteopontin, and bone sialoprotein expression. Studies have investigated the effects of continuous or pulsed laser irradiation, but no data are yet available on the properties of superpulsed laser irradiation. This study thus aimed to investigate the effect of superpulsed laser irradiation on osteogenic activity of human osteoblast-like cells, paying particular attention to investigating the molecular mechanisms underlying the effects of this type of laser radiation. STUDY DESIGN/MATERIALS AND METHODS: Human osteoblast-like MG-63 cells were exposed to 3, 7, or 10 superpulsed laser irradiation (pulse width 200 nanoseconds, minimum peak power 45 W, frequency 30 kHz, total energy 60 J, exposure time 5 minutes). The following parameters were evaluated: cell growth and viability (light microscopy, lactate dehydrogenase release), calcium deposits (Alizarin Red S staining), expression of bone morphogenetic factors (real-time PCR). RESULTS: Superpulsed laser irradiation decreases cell growth, induces expression of TGF-beta2, BMP-4, and BMP-7, type I collagen, ALP, and osteocalcin, and increases the size and the number of calcium deposits. The stimulatory effect is maximum on day 10, that is, after seven applications. CONCLUSIONS: Reported results show that superpulsed laser irradiation, like the continuous and pulsed counterparts, possesses osteogenic properties, inducing the expression of molecules known to be important mediators of bone formation and, as a consequence, increasing calcium deposits in human MG-63 cells. Moreover, the data suggest a new potential role for PPARgamma as a regulator of osteoblast proliferation.
