• International Journal of Oral Biology
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• v.45 no.4
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• pp.204-210
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• 2020

Excessive intake of sodium caused by high salt diet promotes the expression of inflammatory cytokines and differentiation of helper T cells resulting in inflammatory responses. High-glucose diet also contributes to the pathogenesis of periodontitis by inducing changes in the oral microbiome and reducing salivation. However, the effect of a high-salt and glucose diet (HSGD) on the prognosis of periodontitis remains unclear. In this study, a rat model of experimental periodontitis was established by periodic insertion of absorbable sutures containing Porphyromonas gingivalis and Fusobacterium nucleatum strains into the right gingival sulcus to analyze the effect of HSGD on the incidence and progression of periodontitis. The alveolar bone heights (ABH) was measured with microcomputed tomography imaging of the HSGD- and general diet (GD)-treated groups. The right ABH was significantly decreased compared to the left in both groups at 4 weeks after induction of inflammation; however, no significant difference was noted between the groups. Notably, the ABH in the HSGD-treated group was significantly decreased at 8 weeks after induction of inflammation, whereas in the GD-treated group, an increase in the ABH was observed; a significant difference of the ABH was noted between the two groups (p < 0.05). At 12 weeks, recovery of the alveolar bone was observed in both groups, with no significant differences in ABH between the two groups. These findings indicate that the intake of excessive sodium attenuates the recovery rate of the alveolar bone even after the local infectant is removed. In addition, this study demonstrates the use of HSGD in establishing a new animal model of periodontitis.

• Journal of Periodontal and Implant Science
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• v.53 no.1
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• pp.54-68
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• 2023

Purpose: The purpose of this study was to determine whether metformin (MF) could alleviate the expresssion of reactive oxygen species (ROS) and improve the osteogenic ability of bone marrow mesenchymal stem cells derived from diabetic rats (drBMSCs) in vitro, and to evaluate the effect of MF on the ectopic osteogenesis of drBMSCs in a nude mouse model in vivo. Methods: BMSCs were extracted from normal and diabetic rats. In vitro, a cell viability assay (Cell Counting Kit-8), tests of alkaline phosphatase (ALP) activity, and western blot analysis were first used to determine the cell proliferation and osteogenic differentiation of drBMSCs that were subjected to treatment with different concentrations of MF (0, 50, 100, 200, 500 µM). The cells were then divided into 5 groups: (1) normal rat BMSCs (the BMSCs derived from normal rats group), (2) the drBMSCs group, (3) the drBMSCs + Mito-TEMPO (10 µM, ROS scavenger) group, (4) the drBMSCs + MF (200 µM) group, and (5) the drBMSCs + MF (200 µM) + H₂O₂ (50 µM, ROS activator) group. Intracellular ROS detection, a senescence-associated β-galactosidase assay, ALP staining, alizarin red staining, western blotting, and immunofluorescence assays were performed to determine the effects of MF on oxidative stress and osteogenic differentiation in drBMSCs. In vivo, the effect of MF on the ectopic osteogenesis of drBMSCs was evaluated in a nude mouse model. Results: MF effectively reduced ROS levels in drBMSCs. The cell proliferation, ALP activity, mineral deposition, and osteogenic-related protein expression of drBMSCs were demonstrably higher in the MF-treated group than in the non-MF-treated group. H₂O₂ inhibited the effects of MF. In addition, ectopic osteogenesis was significantly increased in drBMSCs treated with MF. Conclusions: MF promoted the proliferation and osteogenic differentiation of drBMSCs by inhibiting the oxidative stress induced by diabetes and enhenced the ectopic bone formation of drBMSCs in nude mice.

• Clinics in Shoulder and Elbow
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• v.26 no.2
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• pp.131-139
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• 2023

Background: Massive rotator cuff tears (RCTs) are complicated by muscle atrophy, fibrosis, and intramuscular fatty degeneration, which are associated with postoperative tendon-to-bone healing failure and poor clinical outcomes. We evaluated muscle and enthesis changes in large tears with or without suprascapular nerve (SN) injury in a rat model. Methods: Sixty-two adult Sprague-Dawley rats were divided into SN injury (+) and SN injury (-) groups (n=31 each), comprising tendon (supraspinatus [SSP]/infraspinatus [ISP]) and nerve resection and tendon resection only cases, respectively. Muscle weight measurement, histological evaluation, and biomechanical testing were performed 4, 8, and 12 weeks postoperatively. Ultrastructural analysis with block face imaging was performed 8 weeks postoperatively. Results: SSP/ISP muscles in the SN injury (+) group appeared atrophic, with increased fatty tissue and decreased muscle weight, compared to those in the control and SN injury (-) groups. Immunoreactivity was only positive in the SN injury (+) group. Myofibril arrangement irregularity and mitochondrial swelling severity, along with number of fatty cells, were higher in the SN injury (+) group than in the SN injury (-) group. The bone-tendon junction enthesis was firm in the SN injury (-) group; this was atrophic and thinner in the SN injury (+) group, with decreased cell density and immature fibrocartilage. Mechanically, the tendon-bone insertion was significantly weaker in the SN injury (+) group than in the control and SN injury (+) groups. Conclusions: In clinical settings, SN injury may cause severe fatty changes and inhibition of postoperative tendon healing in large RCTs. Level of evidence: Level Basic research, controlled laboratory study.

• Journal of Periodontal and Implant Science
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• v.53 no.1
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• pp.20-37
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• 2023

Purpose: Our pilot study showed that a 3-dimensional dual drug delivery scaffold (DDDS) loaded with Chinese herbs significantly increased the regenerated bone volume fraction. This study aimed to confirm the synergistic anti-inflammatory and osteogenic preclinical effects of this system. Methods: The targets and pathways of parthenolide and naringin were predicted. Three cell models were used to assess the anti-inflammatory effects of parthenolide and the osteogenic effects of naringin. First, the distance between the cementoenamel junction and alveolar bone crest (CEJ-ABC) and the bone mineral density (BMD) of surgical defects were measured in a rat model of periodontitis with periodontal fenestration defects. Additionally, the mRNA expression levels of matrix metallopeptidase 9 (MMP9) and alkaline phosphatase (ALP) were measured. Furthermore, the number of inflammatory cells and osteoclasts, as well as the protein expression levels of tumor necrosis factor-alpha (TNF-α) and levels of ALP were determined. Results: Target prediction suggested prostaglandin peroxidase synthase (PTGS2) as a potential target of parthenolide, while cytochrome P450 family 19 subfamily A1 (CYP19A1) and taste 2 receptor member 31 (TAS2R31) were potential targets of naringin. Parthenolide mainly targeted inflammation-related pathways, while naringin participated in steroid hormone synthesis and taste transduction. In vitro experiments revealed significant antiinflammatory effects of parthenolide on RAW264.7 cells, and significant osteogenic effects of naringin on bone marrow mesenchymal stem cells and MC3T3-E1 cells. DDDS loaded with parthenolide and naringin decreased the CEJ-ABC distance and increased BMD and ALP levels in a time-dependent manner. Inflammation was significantly alleviated after 14 days of DDDS treatment. Additionally, after 56 days, the DDDS group exhibited the highest BMD and ALP levels. Conclusions: DDDS loaded with parthenolide and naringin in a rat model achieved significant synergistic anti-inflammatory and osteogenic effects, providing powerful preclinical evidence.

• Journal of Community Nutrition
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• v.6 no.1
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• pp.48-54
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• 2004

The purpose of this study was to examine the effects of dietary protein and exercise on bone mineral density and bone mineral content of growing male rats. Forty male, Sprague-Dawley rats(age 21 days) were assigned to four groups that underwent 9 weeks of experimental treatment. Animals were assigned to one of two exercise treatments (treadmill running or sedentary). The exercise and nonexercise group were fed a diet containing casein or soy with rich isoflavones (3.4mg/g protein). The exercise group ran on a rodent treadmill(speed of 15m/min for 30min) three days per week during the 9-week study period. All rats were fed an experimental diet and deionized water ad libitum for 9 weeks. Total bone mineral density (BMD), total bone mineral content (BMC), total body calcium, spine BMD and BMC, and femur BMD and BMC were determined by using dual energy x-ray absorptiometry (FIXI-mus, GE Lunar Radiation Cooperation, Madison, WI, USA). The soy diet group appears to have a significantly higher total BMD/weight and total BMC/ weight, spine BMD/weight, spine BMC/weight, femur BMD/weight and femur BMC/weight compared to the casein group in nonexercise and exercise. The exercise group had significantly greater total BMD/weight and BMC/ weight, spine BMD/weight and BMC/weight, femur BMD/weight and BMC/weight compared to the nonexercise group when the protein source was casein. The exercise combined soy group had significantly greater total BMD/weight and BMC/weight, spine BMD/weight and BMC/weight, femur BMD/weight and BMC/weight, compared to the exercise combined casein group. The results indicate that exercise had a positive influence on bone mineral density and bone mineral content and soy significantly affect on bone mineral density and bone mineral content for the 9 weeks experimental period. It can be concluded that exercise combined with a soy diet is most beneficial for acquisition of spine bone mineral density in young growing male rats. This convincing evidence suggests that a change in life style such as increasing exercise and consumption of soy protein is a practical strategy for significantly reducing the incidence of osteoporosis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.28 no.3
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• pp.188-195
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• 2002

The purpose of this investigation was to evaluate the relationship between the hydration time of demineralized freeze-dried bone (DFDB) and early new bone formation in rat calvarial defects filled with DFDB. Rats (n = 43) were divided into 4 experimental groups. Standard, transosseous circular defects of the calvaria were made midparietally. In experimental group 1, the defect was grafted immediately after soaking the DFDB. In experimental group 2, the defects were grafted with DFDB after soaking the DFDB for 10 minutes. In experimental groups 3 and 4, the defects were filled after soaking the DFDB for 30 and 60 minutes, respectively. Graft sites were analyzed histologically after healing periods of 1, 2, or 4 weeks. Each group showed similar bone regeneration at each time point by histological analysis. The results of this study were as follows: 1. After 1 week, a significant amount of inflammation, granulation tissue, and edema were found. A small amount of bone was seen, but the amount of bone did not differ between groups. 2. After 2 weeks, a small amount of new bone formation and DFDB resorption were observed. 3. After 4 weeks, a greater amount of new bone formation was observed. The greatest amount of bone formation occurred in experimental group 4 after 4 weeks. We conclude that the hydration time of DFDB does not affect new bone formation and that it is very important to control inflammation in bone grafting.

• The korean journal of orthodontics
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• v.40 no.2
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• pp.106-114
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• 2010

Objective: The aim of this experimental study was to evaluate the effects of direct electrical current stimulation (DECS) on bone regeneration in response to an expansion of the inter-premaxillary suture in the rat. Methods: Sixteen 50 - 60 days old Wistar male rats were separated into two equal groups (control and experimental). Both groups were subjected to expansion, and 30-gram of force was applied to the maxillary incisors with helical-spring. In the experimental group, two metallic-screws were placed at lateral parts of the maxillary segments. Electrodes were connected to the screws. The device was activated with current adjustment to measure $10{\mu}A$ continuously and the current was monitored daily during the expansion and early-retention phase. Bone regeneration in the sutural area was histomorphometrically evaluated including new-bone area (${\mu}m^2$), bone perimeter (${\mu}m$), feret's diameter (${\mu}m$) and newly formed bone (%) parameters. Kruskal-Wallis rank and Mann-Whitney U tests were used for statistical evaluation at p < 0.05 level. Results: Statistical analysis showed significant differences between groups for all investigated histomorphometric parameters. New bone area (p = 0.002), bone perimeter (p = 0.004), feret's diameter (p = 0.002) and newly formed bone percentage (p = 0.002) measurements were significantly higher in the experimental group than the control group. Bone histomorphometric measurements revealed that bone architecture in the DECS group was improved. Conclusions: The application of DECS to an orthopedically expanded inter-premaxillary suture area during the early retention phase stimulated the formation of new bone.

• Journal of Periodontal and Implant Science
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• v.30 no.4
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• pp.835-852
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• 2000

The ultimate goal of periodontal therapy is the regeneration of periodontal tissue and repair of function. For more than a decade there have been many efforts to develop materials and methods of treatment to promote periodontal wound healing. Recently many efforts are concentrated on the regeneration potential of material used in oriental medicine. In some in vitro and in vivo experiments, there have been many evidences that these materials have an effect on bone regeneration. The purpose of this study was to evaluate histologically and radiologically in Sprague-Dawley rats the effects of safflower seed extracts on the regeneration of the calvarial defects surgically produced. So in this study, the critical size defects were surgically produced in the calvarial bone of 30 Sprague-Dawley rats using the 8mm trephine bur. The safflower seed extract was applied into the defect of each rat in experimental group, whereas nothing was applied into the defect of each rat in control group. Rats were sacrificed at 2, 4, 8 weeks following operation and histomorphometric and radiodensitometric analysis were performed. 1. The newly formed bone length was $102.91{\pm}22.05$, $178.29{\pm}24.40$ at 2 week in the each control, experimental group, $130.95{\pm}39.24$, $242.62{\pm}50.33$ at 4 week and $181.53{\pm}76.35$, $240.36{\pm}22.00$ at 8 week($unit,{\mu}m$). In the 2, 4 week, there were statistically significant difference between control and experimental group(P<0.05). 2. The newly formed bone area was $2962.06{\pm}1284.48$, $10648.35{\pm}1284.48$ at 2 week, $5103.25{\pm}1375.88$, $9706.78{\pm}1481.81$ at 4 week, $8046.02{\pm}818.99$, $12057.06{\pm}740.47$ at 8 week($unit,{\mu}m^2$). In every week, there were statistically significant difference between control and experimental group(P<0.05). 3. The radiopacity was $14.26{\pm}.33$, $25.47{\pm}4.33$ at 2 week, $20.06{\pm}9.07$, $26.61{\pm}2.78$ at 4 week, $22.99{\pm}3.76$, $27.29{\pm}1.54$ at 8 week(unit, %). In the 2 week, there was statistically significant difference between control and experimental group(P<0.05). In conclusion, the results of the present study suggest that safflower seed extract initially has an effect on the newly formed bone area, length and radiopacity when it is applied to the calvarial defect of Sprague - Dawley rat. Then. the material has an effect on newly formed bone area and length.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.32 no.5
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• pp.389-395
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• 2010

Purpose: Although it is generally accepted that patients with controlled diabetes have similar rates of success for dental implants as healthy individuals, the use of dental implants in diabetic patients is controversial. In addition, the impact of diabetes on the healing of bone associated with immediately place dental implants is not completely understood. The purpose of this study was to measure bone response to implants radiologically in uncontrolled and insulin-controlled diabetic rats. Materials and Methods: Twenty rats were divided into control, insulin-treated and diabetic groups. The rats received streptozotocin (60 mg/kg) to induce diabetes; animals in the insulin-treated group also received three units of subcutaneous slow-release insulin. Two titanium implants ($1.2{\times}3$ mm) were placed in the extraction socket of the maxillary first molars of the animals and were harvested at 3 days, 1, 2 and 4 weeks. The bone density was measured by digital radiography using gray-level analysis (histogram) in the regions of interest (ROI) at four points: two mesial and two distal to both sides of the implant. Results: The results showed that the osseointegration of the implants was impaired in the diabetic rats compared to the control and the insulin-treated rats. The radiographic evidence demonstrated marked destruction of bone around the implants in the diabetic group. Both the control and the insulin-treated groups had a significantly higher bone density on radiograph than the diabetic group from the 1 week of the experiment (P<0.05 for each comparison). Conclusion: The present study revealed that the immediate placement of titanium implants in the maxilla of diabetic rat lead to delay in the maturation of bone adjacent to implants. It is expected that the reduced predictability of success of immediate implantation in patient with the uncontrolled diabetes.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.1 no.1
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• pp.53-61
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• 2015

Lutetium-177 ($T_{1/2}=6.71day$) is an adequate radionuclide for therapy, which has both beta emission ($E_{max}=497keV$) for therapeutic effect and gamma emission (113 and 208 keV) for imaging. $^{177}Lu$ labeled ethylenediamine-N,N,N',N'-tetrakis (methylene phosphonic acid) (EDTMP) and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminomethylenephosphonate (DOTMP) have been proposed as radiopharmaceuticals for bone pain palliation. In this study, we compared radiochemistry and biodistribution of $^{177}Lu$-EDTMP and $^{177}Lu$-DOTMP. EDTMP and DOTMP were synthesized, and 1 mg of each was labeled with $^{177}Lu$ at pH 7~8 with high efficiency (>98%). For comparative biodistribution studies, $^{177}Lu$-EDTMP or $^{177}Lu$-DOTMP were injected into ICR-mice through tail vein, and then biodistribution data were obtained as percentages of injected dose per gram of tissue (% ID/g). Urine excretions of both agents in mice were checked for 7 days. Rat images were also obtained after injection of $^{177}Lu$-EDTMP or $^{177}Lu$-DOTMP. $^{177}Lu$-DOTMP (100% at 1 min) showed faster labeling than $^{177}Lu$-EDTMP (100% at 30 min). Both of them were stable at least for 21 days at room temperature. High bone uptakes were found for both $^{177}Lu$-EDTMP and $^{177}Lu$-DOTMP: 38.0 and 34.1% ID/g at 3 hr, respectively; and 33.2 and 18.8% ID/g at 7 day, respectively. Rapid excretions to urine were found for both agents ($^{177}Lu$-EDTMP: 56%, $^{177}Lu$-DOTMP: 63% at 1 day). Other organs showed very low uptakes. Rat images of both $^{177}Lu$-EDTMP and $^{177}Lu$-DOTMP showed high bone uptakes and low soft tissue uptakes. In conclusion, both $^{177}Lu$-EDTMP and $^{177}Lu$-DOTMP showed high potential as bone pain palliation agents. $^{177}Lu$-EDTMP showed higher bone uptake and slower bone clearance in mice than those of $^{177}Lu$-DOTMP.