Fibroblast growth factor-2 (FGF2) plays a critical role in osteoblastic cell proliferation. Collagen gel-sponge composite is an effective scaffold for tissue engineering. The purpose of this study was to evaluate whether addition of FGF2 to collagen gel-sponge composite promotes bone augmentation in rats. The rats were assigned to groups designated F0, F3 and F15, and received implantation of collagen gel-sponge composite containing 0, 3 and 15 µg FGF2, respectively, into a cranial bone defect. Specimens were prepared 1, 2 and 5 weeks after surgery for histologic and histomorphometric analysis. Newly formed bone area in groups F3 and F15 was significantly greater than that in group F0 at all stages. These results suggest that FGF2-loaded collagen gel-sponge composite scaffold stimulates bone augmentation and might provide a more effective bone engineering approach.
The in vivo reaction against metal particles is still not well understood. We implanted particulate copper (Cu), nickel (Ni) and titanium (Ti) in subcutaneous tissues of the back of mice for 1 week and evaluated metal-implant-induced tissue reactions. In histological observations, Cu and Ni induced strong and moderate inflammation, respectively, while Ti caused little inflammation. Transmission electron microscope (TEM) observations clarified that a major inflammatory and body-defense cell was neutrophil against Cu and Ni, while no inflammatory cells were found around Ti. We speculated that tissue reactions against Cu and Ni were caused by eluted Cu and Ni ions, respectively, in the nearby tissues.
Computation analysis of bisphophonates (BPs) and BP/Ca complexes were performed by using personal computer. Molecular mechanics (MM) calculations and molecular orbital (MO) calculations were performed. Six kinds of BPs, etidronate, clodronate, pamidronate, alendronate, risedronate, zoledronate, were studied. The three-dimensional structure with the lowest steric energy of BPs and BP/Ca complexes were obtained by MM calculation. Steric energies of BP/Ca complexes were higher than those of BPs. Correlation between ΔE (energy differences of BP/Ca complex and BP) and presumed temporary activity index of BPs was found. The energies of highest occupied MO (HOMO) and lowest unoccupied MO (LUMO) were obtained by MO calculations. A slight correlation was found between ΔE'(energy differences between LUMO of Ca ion and HOMO of BPs) and presumed temporary activity index of BPs. It revealed that ΔE and ΔE' will play a significant role in the activity of BPs. MM and MO calculations will be one of the useful tools which analyze and understand the role of BPs or other biological compounds.
Objectives: In order to histopathologically investigate biological reactions to materials used for scaffolds, we examined the cytotoxicity to calcium particles in vitro and bioabsorption in vivo. Materials and methods: Calcium phosphate-coated calcium carbonate particles 30µm in diameter (calcium particles) were used for the materials. In vitro; Normal human dermal fibroblasts (NHDF) and human umbilical vein endothelial cells were co-cultured and seed with calcium particles. In vivo; The calcium particles were used as the experimental group, and rat bone, mouse bone and propylene glycol alone serving as the control group were implanted under the dorsal skin of rats. Following transplantation at 2, 4, 6 and 8 weeks, the skins were resected. The sections stained with HE, DAPI, anti-rat CD3, anti-immunoglobulin, and anti-rat macrophage, were observed histopathologically. Results: The co-cultured cells grew densely around the calcium particles, and the latter were assimilated by granulation tissue comprised of CD3 dominant lymphocytes, macrophages, and foreign-body giant cells. The particles were phagocytosed by foreign-body giant cells with 10-20 nuclei. The bioabsorption of the calcium particles was similar to that of rat bone, but different from that of mouse bone.
Chemokines regulate the homeostatic trafficking of lymphocytes and lymphocyte influx to sites of injury and inflammation. Here, we investigate the role of CXCL12 on the migration and signaling of RAW264 cells. We find that CXCL12-induced migration is enhanced in a dose-dependent manner, and CXCL12 enhances phosphorylation of ERK1/2 and AKT. Furthermore, this CXCL12-stimulated migration and phosphorylation is inhibited in the presence of the MEK1/2 inhibitor U0126, and the PI 3-K inhibitors, Wortmannin and LY294002. However, MEK1/2 inhibitor does not affect phosphorylation of the PI 3-K enzyme AKT, and PI 3-K inhibitors do not affect the phosphorylation of ERK1/2. This suggests that stimulation of ERK1/2 and AKT by CXCL12 occurs via an independent signaling pathway, which enhances migration of RAW264 cells.
Manuscripts submitted to the official journal of The Japanese Association of Regenerative Dentistry are processed by multiple review system. Some manuscripts are rejected based on a negative evaluation by reviewers. The most important point for considering publication in the journal is the fundamental study design of the manuscript. There are many manuscripts whose results are inconsistent with the purposes of the study. Many manuscripts do not provide adequate discussion. Furthermore, there are many manuscripts whose study design only follows studies published in another journal. Recently, there have also been serious issues regarding the proper handling of copyrighted materials and plagiarism of other studies. The following section describes common reasons for revising or rejecting manuscripts submitted to the journal.