To investigate differences in curative effect of bone mesenchymal stem cells grafting via arteries and veins on 6-hour ischemia-reperfusion. A 2-hour middle cerebral artery ischemia-reperfusion model was established in 27 SD female rats. BMSCs were isolated and cultured using the whole bone marrow adherent technique, identified by flow cytometry. The expression of surface antigen CD90, CD29, CD106, CD11b, CD34 and CD45 on BMSCs was 95.7%, 97.3%, 52.7%, 6.01%, 2.95% and 2.26%, respectively. When compared with two PBS groups, the neurological severity was ameliorated significantly and expression of GFAP and Bcl-2 in infarction border zone were further up-regulated in two BMSCs groups. Moreover, the levels of TNF-a in serum and TUNEL staining in brain tissue were significantly reduced after transplantation. BMSC grafting via caudal veins was the best approach during the early periods of ischemia-reperfusion due to minor trauma and the rich source of BMSCs. It provides a possible way to future clinical treatment of cerebral infarction by stem cell infusion to patients.

Autogenous bone grafting involves a second surgery and is limited by the availability of collectable bone. Coral products commercially available as bone grafts are composed of corals in their natural form. Cultured corals are recommended as a substitute to overcome the threat of extinction of natural corals. The purpose of this study was to investigate the potential of cultured coral scaffolds for periodontal tissue regeneration in class II furcation defects in dogs. The cultured coral used for this study was characterized using scanning electron microscopy (SEM), powder X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy. Twelve mandibular premolar teeth from two female beagle dogs were used. Furcation defects of three left mandibular premolar teeth of each dog received the cultured coral. A control group consisting of the right mandibular premolar teeth from each dog received no implant material within the furcation defects. The dogs were then sacrificed 8 weeks post-surgery, and healing was evaluated histologically and radiologically using micro-computed tomography analysis. SEM micrographs showed a tri-dimensional ceramic structure with pore size ranging 50-250 mm. The surface of the cultured coral particles was covered with numerous rough, porous processes. XRD and FTIR results showed that the cultured coral exhibited both aragonite and calcite phases, referred to as dimorphism. The cultured coral particles implanted into the defects were completely resorbed and replaced by bone with either a Haversian structure or without any inflammatory reaction. A well-organized periodontal ligament bridging the new bone and cementum was regenerated to the top of the furcation space. Histopathological evaluation suggests that cultured coral scaffolds have the potential to regenerate periodontal tissue in class II furcation defects in dogs.

Mesenchymal stem cells are known to exist in pulp tissue. However, the detailed characteristics of the stem cells have not been elucidated. Recently, the presence of novel Muse cells which has been reported. Researches mentioned that Muse cells exist in all mesenchymal tissues such as in the bone marrow, skin and adipose tissue. However, there is hardly any report regarding the existence of Muse cells in oral tissues. Therefore, the purpose of the study was to determine the presence of Muse cells in dental pulp tissue. About 0.5% of SSEA (Stage-Specific Embryonic Antigen)-3 positive cells were isolated from dental pulp cells by cell sorter. The isolated cells showed self-renewal ability in addition to expressing the genes representing the three germ layers. Furthermore, the isolated cells showed a high calcification ability when subjected to calcification-inducing medium. Calcification ability was shown using alkaline phosphatase staining, alizarin red staining and quantification of calcium. The results suggest that SSEA-3 positive cells derived from human dental pulp tissue are similar to Muse cells, highly capable of differentiating into osteogenic cells. Isolated these cells from the dental pulp tissue is highly advantageous since they are less invasive compared to other cells. Hence, the dental pulp tissue is envisioned to be the source of new cells beneficial in regenerative medicine.

The purpose of this study was to use a rat spinal fusion model to determine whether osteoconduction of HA is improved by the addition of SF. The SF/HA composite was derived by mixing HA sols with SF sols. In an in vitro study, water absorption testing, cell compatibility and compression test were done. In an in vivo study, 30 S-D male rats had surgery for posterolateral lumbar fusion. Group I rats were implanted with SF/HA composites; Group II rats were implanted with HA; Group III rats were implanted with an autograft. Fusion was evaluated by water absorption test, manual palpation, radiology and histology. The results showed that water absorption was significantly higher with the SF/HA composite compared with HA. Manual palpation and radiology showed a higher rate of fusion in the SF/HA group. Histology also showed better results for the SF/HA group. In, conclusion, SF can modify the osteoconduction of HA. SF/HA composites make good bone graft alternatives in spinal fusion, although additional research needs to be done.

The incidence of osteonecrosis of the jaw (ONJ) in association with bisphosphonate (BP) preparations (medication-related ONJ, MRONJ) has reportedly increased rapidly in the recent times. Despite the increase, specific cure remains to be established. In this study, MRONJ model rats were constructed, the action and effect of dental pulp stem cell-conditioned medium (DPSC-CM) on MRONJ were evaluated. Following BP preparation (sodium zoledronate, ZOL) administration to rats via the jugular vein, the first molar of the right maxilla was extracted to obtain MRONJ model rats, which served as the control group. Model rats were further administered with either Dulbecco Modified Eagle Medium (DMEM) or DPSC-CM via the jugular vein. These groups were comparatively analyzed, and the jawbone at the site of dental extraction was used as the test sample. Compared with control group and DMEM group, the DPSC-CM group exhibited unique macroscopic findings characterized by the narrowed width of bone exposure and increased mucous coating. Histological analysis revealed a significant decrease in the number of hollow bone lacunae, implying improved osteonecrosis. In immunohistological studies, it was discerned that ZOL administration promoted osteoprotegerin (OPG) production in the osteoblasts and suppressed the synthesis of receptor activator of nuclear factor kappa-B ligand (RANKL). Conversely, the DPSC-CM group displayed suppressed OPG and accelerated RANKL expressions, with an increase in the number of vascular endothelial growth factor-positive cells. Furthermore, Tartrate-resistant acid phosphatase/alkaline phosphatase (TRAP/ALP) staining suggested improved bone remodeling capability in this group. Thus, DPSC-CM administration improves ischemic osteonecrosis and may, therefore, be an effective therapeutic option.

Diet is an important factor maintaining bone health. Several studies have reported that extracts of brown marine algae containing polyphenols positively regulate bone metabolism. Therefore, we examined the effects of Eisenia bicyclis (Japanese name, Arame), an edible brown marine algae, on cell proliferation, alkaline phosphatase activity, collagenous and non-collagenous bone matrix protein expressions, and mineralized nodule formation using ROS17/2.8 cells as osteoblasts. A thermal extract derived from E. bicyclis was applied to a Diaion HP-20 column, and a portion of the 50% ethanol fraction was used as the E. bicyclis extract. The cells were cultured in the presence or absence of E. bicyclis extract, and cell proliferation and alkaline phosphatase activity were determined. The expressions of type I collagen, bone sialoprotein, and osteopontin were examined at the mRNA level using real-time PCR. Mineralized nodule formation was detected via alizarin red staining. Alkaline phosphatase activity and the expressions of type I collagen, bone sialoprotein, and osteopontin were increased in the presence of E. bicyclis extract, whereas cell proliferation was not affected. The E. bicyclis extract also increased mineralization. Together, these results indicate that the extract induces osteogenic function in osteoblasts.

The entheses of the masticatory muscles differ slightly from those of the trunk and limb muscles. However, the bones of the skull are subject to various functional pressures, including masticatory force, resulting in a complex relationship between bone structure and muscle function that remains to be fully elucidated. The present study aimed to clarify aspects of masseter muscle-tendon-bone morphological characteristics and local load environment through quantitative analysis of biological apatite (BAp) crystallite alignment and collagen fiber orientation together with histological examination of the entheses. Result of histological observation, the present findings show that, in the entheses of the masseter muscle in the first molar region, tendon attaches to bone via unmineralized fibrocartilage, while some tendon collagen fibers insert directly into the bone, running parallel to the muscle fibers. Furthermore, BAp crystallites in the same region show uniaxial preferential alignment at an angle that matches the insertion angle of the tendon fibers. Conversely, in the entheses of the masseter muscle in the third molar region, the tendon attaches to the bone via a layer of thickened periosteum and chondrocytes. As in the first molar region, the results of bone quality analysis in the third molar region showed BAp crystallite alignment parallel to the orientation of the tendon fibers. This indicates that the local mechanical environment generates differences in enthesis morphology. The present study showed a greater degree of uniaxial BAp crystallite alignment in entheses with direct insertion rather than indirect tendon-bone attachment and the direction of alignment was parallel to the orientation of tendon fibers. These findings suggest that functional pressure from the masseter muscle greatly affects bone quality as well as the morphological characteristics of the enthesis, specifically causing micro- and nanostructural anisotropy in the direction of resistance to the applied pressure.

This study aims to evaluate the ability of poly(propylene carbonate) (PPC)-loaded nanohydroxyapatite (nHAp) membrane to regenerate bones. Methods: Six New Zealand white rabbits were randomly and equally divided into two groups. Four 6 mm diameter transosseous round defects were made at the parietal bone of each rabbit. One defect was not covered with the membrane, and the others were covered with 10% or 20% nHAp/PPC membrane or HEAL-ALL membrane. Animals of each group were sacrificed at the 4 and 12 weeks after the operation, respectively. The rabbit parietal bones were removed for radiological and histological evaluation. Results: Micro-computed tomography results showed that the bone regeneration of the experimental group was significantly higher than that of the control group in the absence of bone powder after 4 and 12 weeks, and the 20% nHAp/PPC group showed the most significant effect on bone regeneration. Histological analysis found that the nHAp/PPC membranes and HEAL-ALL membranes of the experimental groups prevent the growth of soft tissues during bone regeneration. In summary, the nHAp/PPC membrane showed good biocompatibility during the repair of rabbit parietal defects, and the 20% nHAp/PPC membrane is prominent.

To investigate the influence of occlusal support and the presence and position of mandibular third molars on the incidence of mandibular condylar fractures. Records of 222 patients who presented with mandibular fracture at the Department of Oral and Maxillofacial Surgery, Kagawa Prefectural Central Hospital, from 2006 to 2019 were retrospectively analyzed. The following variables were investigated: age, sex, cause of fracture, the presence and state (impaction and angulation) of mandibular third molars, the site of mandibular fracture, and the presence of occlusal support for molars. Various risk factors for mandibular condylar head and subcondylar fractures were investigated. The majority of fractures were caused by a fall. The risk of mandibular subcondylar fractures was significantly higher in patients with occlusal support and mandibular third molars. The risk of mandibular condylar head fractures was significantly higher in patients without occlusal support or mandibular third molars. The position and angulation of mandibular third molars did not show significant difference between occurrences of head or subcondylar fractures. This study demonstrated that occlusal support and the presence of mandibular third molars significantly increased the risk of subcondylar fractures. One the contrary, their absence increased the risk of condylar head fractures.

Although mineral trioxide aggregate (MTA) has excellent sealing properties and biocompatibility and is currently widely used in various applications including direct pulp capping, several problems associated with its use, such as variable curing time and inconsistent physical properties, persist. We have developed a chemically curable, resin-modified type of MTA material (PCX-TBB) using tri-n-butylborane (TBB) as a polymerization initiator to improve the abovementioned problematic characteristics. We previously reported that PCX-TBB exhibited good physicochemical properties, excellent calcium releasing ability, and enhanced hard tissue induction ability compared with those of TheraCal LC^® (Bisco, Schaumburg, IL, USA), which is already used clinically. In the present study, we further clarified the biocompatibility and healing ability of PCX-TBB as a direct pulp capping material. The histopathological changes when PCX-TBB and TheraCal LC^® were applied to the wound-exposed pulps of dogs were investigated. We evaluated the grade of inflammatory cell infiltration and state of dentin bridge formation 7 days and 69 days after the application of PCX-TBB and TheraCal LC^®. It was found that the inflammatory changes in the repair of cavities via pulp capping using PCX-TBB were the same as those observed with the use of TheraCal LC^®. The dentin bridges formed 69 days after the application of both the materials, and the use of PCX-TBB resulted in a greater extent of dentin bridge formation in each cavity than that achieved by TheraCal LC^®. The dentin bridges formed with the use of PCX-TBB were greater in area than that of the largest dentin bridge formed using TheraCal LC^® in at least 70% of the specimens. These findings suggest that PCX-TBB is more biocompatible and effective as a direct pulp capping material than TheraCal LC^®.