Secretoneurin, a Neuropeptide, Enhances Bone Regeneration in a Mouse Calvarial Bone Defect Model

BACKGROUND@#This study investigates the effects of a neuropeptide, secretoneurin (SN), on bone regeneration in an experimental mouse model. @*METHODS@#The effects of SN on cell proliferation, osteoblast marker genes expression, and mineralization were evaluated using the CCK-8 assay, quantitative reverse transcriptase polymerase chain reaction (RT-PCR), and alizarin red S staining, respectively. To examine the effects of SN on bone regeneration in vivo, bone defects were created in the calvaria of ICR mice, and 0.5 or 1 lg/ml SN was applied. New bone formation was analyzed by micro-computed tomography (micro-CT) and histology. New blood vessel formation was assessed by CD34 immunohistochemistry. @*RESULTS@#SN had no significant effect on proliferation and mineralization of MC3T3-E1 cells. However, SN partially induced the gene expression of osteoblast differentiation markers such as runt-related transcription factor 2, alkaline phosphatase, collagen type I alpha 1, and osteopontin. A significant increase of bone regeneration was observed in SN treated calvarial defects. The bone volume (BV), BV/tissue volume, trabecular thickness and trabecular number values were significantly increased in the collagen sponge plus 0.5 or 1 lg/ml SN group (p < 0.01) compared with the control group. Histologic analysis also revealed increased new bone formation in the SN-treated groups. Immunohistochemical staining of CD34 showed that the SN-treated groups contained more blood vessels compared with control in the calvarial defect area. @*CONCLUSION@#SN increases new bone and blood vessel formation in a calvarial defect site. This study suggests that SN may enhance new bone formation through its potent angiogenic activity.

Secretoneurin, a Neuropeptide, Enhances Bone Regeneration in a Mouse Calvarial Bone Defect Model

BACKGROUND@#This study investigates the effects of a neuropeptide, secretoneurin (SN), on bone regeneration in an experimental mouse model. @*METHODS@#The effects of SN on cell proliferation, osteoblast marker genes expression, and mineralization were evaluated using the CCK-8 assay, quantitative reverse transcriptase polymerase chain reaction (RT-PCR), and alizarin red S staining, respectively. To examine the effects of SN on bone regeneration in vivo, bone defects were created in the calvaria of ICR mice, and 0.5 or 1 lg/ml SN was applied. New bone formation was analyzed by micro-computed tomography (micro-CT) and histology. New blood vessel formation was assessed by CD34 immunohistochemistry. @*RESULTS@#SN had no significant effect on proliferation and mineralization of MC3T3-E1 cells. However, SN partially induced the gene expression of osteoblast differentiation markers such as runt-related transcription factor 2, alkaline phosphatase, collagen type I alpha 1, and osteopontin. A significant increase of bone regeneration was observed in SN treated calvarial defects. The bone volume (BV), BV/tissue volume, trabecular thickness and trabecular number values were significantly increased in the collagen sponge plus 0.5 or 1 lg/ml SN group (p < 0.01) compared with the control group. Histologic analysis also revealed increased new bone formation in the SN-treated groups. Immunohistochemical staining of CD34 showed that the SN-treated groups contained more blood vessels compared with control in the calvarial defect area. @*CONCLUSION@#SN increases new bone and blood vessel formation in a calvarial defect site. This study suggests that SN may enhance new bone formation through its potent angiogenic activity.

Pentamidine Inhibits Titanium Particle-Induced Osteolysis In Vivo and Receptor Activator of Nuclear Factor-κB Ligand-Mediated Osteoclast Differentiation In Vitro

BACKGROUND: Wear debris-induced osteolysis leads to periprosthetic loosening and subsequent prosthetic failure. Since excessive osteoclast formation is closely implicated in periprosthetic osteolysis, identification of agents to suppress osteoclast formation and/or function is crucial for the treatment and prevention of wear particle-induced bone destruction. In this study, we examined the potential effect of pentamidine treatment on titanium (Ti) particle-induced osteolysis, and receptor activator of nuclear factor-κB ligand (RANKL)-induced osteoclastogenesis. METHODS: The effect of pentamidine treatment on bone destruction was examined in Ti particle-induced osteolysis mouse model. Ti particles were implanted onto mouse calvaria, and vehicle or pentamidine was administered for 10 days. Then, calvarial bone tissue was analyzed using micro-computed tomography and histology. We performed in vitro osteoclastogenesis assay using bone marrow-derived macrophages (BMMs) to determine the effect of pentamidine on osteoclast formation. BMMs were treated with 20 ng/mL RANKL and 10 ng/mL macrophage colony-stimulating factor in the presence or absence of pentamidine. Osteoclast differentiation was determined by tartrate-resistant acid phosphatase staining, real-time polymerase chain reaction, and immunofluorescence staining. RESULTS: Pentamidine administration decreased Ti particle-induced osteoclast formation significantly and prevented bone destruction compared to the Ti particle group in vivo. Pentamidine also suppressed RANKL-induced osteoclast differentiation and actin ring formation markedly, and inhibited the expression of nuclear factor of activated T cell c1 and osteoclast-specific genes in vitro. Additionally, pentamidine also attenuated RANKL-mediated phosphorylation of IκBα in BMMs. CONCLUSION: These results indicate that pentamidine is effective in inhibiting osteoclast formation and significantly attenuates wear debris-induced bone loss in mice.

Synaptic connectivity and ultrastructrue of the masseteric muscle spindle afferent trigeminals according to geometric location in the trigeminal motor nucleus of the cat / 대한해부학회지

The purpose of this study was to investigate any relationship between the geometric factors of synaptic contacts of muscle spindle afferent terminals and masseteric motor neurons in the trigeminal motor nucleus. Terminals from the masseteric muscle spindle afferents were stained with intra-axonal injection of HRP and were examined electronmi-croscopically with serial sections at the central and peripheral regions of trigeminal motor nucleus of the cat. The number of terminals examined were 76 in peripheral and 105 in central region. The results obtained were as follows. 1. Most of the labeled terminals showed simple synaptic connectivity. Each terminals in peripheral and central region made synaptic contact with 1 to 5 neuronal profiles. Two or three labeled terminals were occasionally seen to make synaptic contact with the same dendrite. 2. The average number of postsynaptic proximal dendrite per labeled terminal was higher in the central region than in the peripheral region. In contrast, that of postsynaptic distal dendrite per labeled terminal was higher in the peripheral region than in the central region. 3. The average diameter of postsynaptic dendrites in the central region was larger than that in the peripheral region. This imply terminals in the peripheral region contacted with further distal part of the distal dendrite than that in the central region. These results indicate that synaptic connectivity associated with the spindle afferents from masseteric muscle is different according to their geometric location within the trigeminal motor nucleus and suggest that there will be precise interrelationship between the morphology, pattern of synaptic connectivity and functions of muscle spindle afferents.

Ultrastructural analysis of glutamate immunoreactive primary afferent terminals in the trigeminal nucleus principalis and trigeminal nucleus oralis of the rat / 대한해부학회지

The present study was aimed to investigate the ultrastructure of the primary afferent terminals and whether glutamate may be a transmitter in these terminals within the trigeminal nucleus principalis and oralis of the rat. Labeling of primary afferent terminals was performed by the injection of the CTB-HRP into the trigeminal ganglion. Ultrastructural analysis and assessment of the glutamate like immunoreactivity by the immunogold technique was performed with the 66 peroxidased labeled boutons in the nucleus principalis and 62 in the nucleus oralis. Labeled boutons were presynaptic to dendritic shafts of the secondary neurons and postsynaptic to the pleomorphic vesicles containing endings (p-endings). Most of the labeled boutons made synaptic contact with the dendritic shafts. A little labeled boutons in the nucleus oralis but no in the nucleus principalis was observed to make synaptic contact with the soma or proximal dendrite. Most of the labeled boutons made synaptic contact with one to three neurofiles, but labeled boutons showing complex synaptic connections, such as those with five or more neurofiles, were more in principalis than in oralis. The average diameter of p-endings were smaller than that of labeled boutons (p<0.05). The diameter of the postsynaptic dendritic shafts were smaller in nucleus principalis than in nucleus oralis, thus indicated that the labeled boutons made synaptic contact with more distal portion of the postsynaptic dendrite in the nucleus principalis than in the nucleus oralis. The gold particle density over the labeled boutons were significantly higher than that over the p-endings and average tissue particle density. They were ranged from 110 to 430% of the average tissue particle density. These findings indicate that synaptic connection of the primary afferent terminals is organized in different manner in nucleus principalis and oralis, and suggest that glutamate is involved as neuroactive substance in the primary afferent terminals of the trigeminal system.

Bucco-lingual Implant Path in the Posterior Mandible / 체질인류학회지

The purpose of this study is to investigate the cross -sectional anatomy of posterior mandibular body for proper determination of bucco -lingual implant path. Using fifty -four human mandibles, negative images of each mandible were made of agar impression material. The agar blocks were cut through the imaginary long axis of each root of three molars (M1M, M1D, M2M, M2D and M3). The depth of submandibular fossa, the angulation of long axis of mandibular body and tooth, and the length, angulation and ratio of alveolar bone superior to mylohyoid ridge and basal bone inferior to mylohyoid ridge were measured. The results obtained were as follows; 1. All of the measured angulations were decreased as it moves from M1M to M3. 2. The correlation coefficients among the angulation of the mandibular bone and the crown axis showed the high relationship (r=0.793), and the crown axis was steeper than the mandibular bone axis by 6.2 at M1M and 7.6 at M2M. 3. The length of upper alveolar bone was decreased, but that of inferior basal bone was increased as it moves from M1M to M3. 4. The depth of submandibular fossa was increased as it moves from M1M to M3. These results indicate that the angulation of implant path at the posterior mandible must be tilted more than wax -up crown axis by 6.2 at mesial root of 1st molar and by 7.6 at mesial root 2nd molar area for prevention of lingual cortical bone perforation during implant surgery.