ABSTRACT
Recent research has shown that platinum nanoparticles (nano-Pt) efficiently quench reactive oxygen species (ROS) as a reducing catalyst. ROS have been suggested to regulate receptor activator of NF-κB ligand (RANKL)-stimulated osteoclast differentiation. In the present study, we examined the direct effects of platinum nano-Pt on RANKL-induced osteoclast differentiation of murine pre-osteoclastic RAW 264.7 cells. The effect of the nano-Pt on the number of osteoclasts was measured and their effect on the mRNA expression for osteoclast differentiation was assayed using real-time PCR. Nano-Pt appeared to have a ROS-scavenging activity. Nano-Pt decreased the number of osteoclasts (2+ nuclei) and large osteoclasts (8+ nuclei) in a dose-dependent manner without affecting cell viability. In addition, this agent significantly blocked RANKL-induced mRNA expression of osteoclastic differentiation genes such as c-fms, NFATc1, NFATc2, and DC-STAMP as well as that of osteoclast-specific marker genes including MMP-9, Cath-K, CLC7, ATP6i, CTR, and TRAP. Although nano-Pt attenuated expression of the ROS-producing NOX-family oxidases, Nox1 and Nox4, they up-regulated expression of Nox2, the major Nox enzyme in macrophages. These findings suggest that the nano-Pt inhibit RANKL-stimulated osteoclast differentiation via their ROS scavenging property. The use of nano-Pt as scavengers of ROS that is generated by RANKL may be a novel and innovative therapy for bone diseases.
Subject(s)
Nanoparticles , Osteoclasts/drug effects , Platinum/chemistry , Reactive Oxygen Species/metabolism , Animals , Cell Differentiation/drug effects , Cell Line , Dose-Response Relationship, Drug , Free Radical Scavengers/administration & dosage , Free Radical Scavengers/pharmacology , Gene Expression Regulation/drug effects , Macrophages/drug effects , Macrophages/metabolism , Mice , Osteoclasts/metabolism , Platinum/administration & dosage , RANK Ligand/antagonists & inhibitors , RNA, Messenger/metabolismABSTRACT
Since adhesive technology was introduced into dental field, metal-based restoration has been gradually replaced by metal-free restoration. Using the adhesive technology, minimum invasive technique has been possible in daily clinical practice as well as esthetic tooth-colored restorations have become very popular all over the world.One of the current issues of the dental adhesive is durability of bond between tooth structure and adhesive resin. Several approaches to overcome the issues have been carried out. Self-etching approach is believed to create durable bond because demineralization of superficial tooth surface is very shallow. Other approach is to utilize the inhibitor of enzymes which are suggested to catalyze the decomposition of resin composites and are always secreted within the oral environment.In the present study, Colloidal Platinum Nanoparticles (CPN) was applied before the application of 4-META/MMA-TBB resin cement as the third possibility to prolong the durability of bond. This implies that the use of the CPN solution would create higher conversion at the interface compared with conventional bonding procedures.
