Beneficial effects of the fructus Sophorae extract on experimentally induced osteoporosis in New Zealand white rabbits

Sophora japonica is a source of several flavonol, flavone and isoflavone glycosides that are reported to positively affect menopausal symptoms including osteoporotic complications. In the present study fructus Sophorae extract (FSE) was administered orally for three months at a dose of 200 mg kg^-1 in ovariectomized (OVX) New Zealand rabbits. 3D computed tomography scans and histopathological images revealed microstructural disturbances in the bones of the castrated animals. FSE recovered most of the affected parameters in bones in a manner similar to zoledronic acid (ZA) used as a positive control. The aglycones of the main active compounds of FSE, daidzin, and genistin, were docked into the alpha and beta estrogen receptors and stable complexes were found. The findings of this study provide an insight into the effects of FSE on bone tissue loss and suggest that it could be further developed as a potential candidate for the prevention of postmenopausal osteoporotic complications.

Effect of Simvastatin and Low-Level Laser Therapy on Sutural Bone Formation After Expansion in Rats: Biomechanical, Computed Tomography and Immunohistochemical Assessment

Introduction: The application of low-level laser therapy (LLLT) and some medications have been shown to accelerate bone formation in rapid palatal expansion (RPE). A combination of these two therapeutic modalities may reduce the time required for the retention period. This study sought to assess the effects of simvastatin and LLLT, alone and combined, on sutural bone formation in rats. Methods: Sixty male Wistar rats averagely weighing 150 g were divided into five groups (n=12) of control (group 1), 5 mg simvastatin (group 2), 10 mg simvastatin (group 3), LLLT (group 4), and LLLT plus 10 mg simvastatin (group 5). The expansion appliance was placed in the parietal bone in all groups. One week after placing the appliance, the spring was fixed with Duralay acrylic resin to serve as a retainer during the rest of the experiment. The rats were sacrificed after 30 (for biomechanical and computed tomography [CT] assessments) or 60 days (for biomechanical, CT and immunohistochemical [IHC] assessments). Results: Groups 3 and 4 showed a significant improvement in osteogenesis (confirmed by CT findings, histological analysis and biomechanical test) compared to the control group. Group 5 was significantly superior to all other groups in terms of all parameters (P<0.001). Group 2 and the control group were not significantly different (P>0.05). Conclusion: Although LLLT, simvastatin treatment and the combination of both significantly improved sutural bone formation in rats compared to the control group, the combined treatment showed significantly superior clinical results compared to other interventions.

Effect of salvianolic acid B on new bone formation in the orthopedically expanded suture

OBJECTIVES

To determine the effects of Salvianolic acid B (Sal B) on new bone formation in the orthopedically expanded premaxillary sutures in rats.

MATERIALS AND METHODS

The sample consisting of Sprague Dawley rats (male, n = 14) was split in half by random selection: the experiment group (Sal B) and the control group. The premaxillary suture of each rat was expanded by bonding an open-loop spring to two maxillary incisors, each end to one tooth. A 5-day expansion period followed by a 12-day retention period was conducted. The 17-day intraperitoneal administration of Sal B was performed daily for the experiment group at a dose of 40 mg/kilo. The trial was completed after sacrificing the rats and dissection of the premaxillae for histological analysis. The amount of new bone, quantity of capillaries and intensity of inflammatory cells were histomorphometrically determined while the quantities of osteoblasts and osteoclasts were determined immunohistochemically.

RESULTS

The Sal B group was significantly different from the control group and had greater quantities of new bone, capillaries, inflammatory cells, osteoblasts, and osteoclasts.

CONCLUSIONS

Salvianolic acid B displays a positive effect during premaxillary expansion with a greater number of capillaries potentially in association with higher bone formation and improved angiogenesis in rats.

Is there an optimal initial amount of activation for midpalatal suture expansion? : A histomorphometric and immunohistochemical study in a rabbit model

OBJECTIVE

Accelerated bone-borne expansion protocols on sutural separation and sutural bone formation were evaluated via histomorphometry and immunohistochemistry to determine the optimal initial activation without disruption of bone formation.

MATERIALS AND METHODS

Sixteen New Zealand white rabbits were randomly divided into four groups. Modified Hyrax expanders were placed across the midsagittal sutures and secured with miniscrew implants with the following activations: group 1 (control), 0.5 mm expansion/day for 12 days; group 2, 1 mm instant expansion followed by 0.5 mm expansion/day for 10 days; group 3, 2.5 mm instant expansion followed by 0.5 mm expansion/day for 7 days; and group 4, 4 mm instant expansion followed by 0.5 mm expansion/day for 4 days. After 6 weeks, sutural expansion and new bone formation were evaluated histomorphometrically. Statistical analysis was performed using Kruskal-Wallis/Mann-Whitney U tests and Spearman's rho correlation (p < 0.05).

RESULTS

The smallest median sutural separation was observed in group 1 (3.05 mm) and the greatest in group 4 (4.57 mm). The lowest and highest amount of bone formation were observed in group 4 (55.82%) and in group 3 (66.93%), respectively. Immunohistochemical analysis revealed significant differences in median levels of alkaline phosphatase and osteopontin expression between all experimental groups. The highest level of these proteins was attained in group 3, followed by groups 2, 1, and 4, respectively.

CONCLUSIONS

Sutural appositional bone formation corresponded with the amount of initial expansion to a point. When initial expansion was increased to 4 mm, sutural bone remodeling was disturbed and new bone formation was decreased. The most effective sutural expansion was achieved with 2.5 mm initial activation followed by 0.5 mm expansion/day for 7 days.

Effects of Zoledronic Acid on Orthodontic Tooth Movement in Rats

The purpose of this study was to assess the effects of the administration of zoledronic acid (ZA) during orthodontic movement in rats. A hundred and twenty male Wistar rats were applied force of 30 cN with spring closed nickel-titanium to move the upper right first molar to mesial. In the Control Movement group (CM), only tooth movement was performed; the Control Acid Zoledronic group (CAZ) received a single dose (0.1 mg/kg) of ZA; the Experimental Acid Zoledronic group (EAZ) received a single dose (0.1 mg/kg) one week prior to the start of tooth movement; and the Control Without movement group (CWM) that received no drug and without application of tooth movement. The animals were euthanized after 3, 7 and 14 days. Tooth movement was measured using a caliper, the number of osteoclasts using TRAP staining, the expression of mature and immature collagen using picrosirius staining, and the presence of hyaline areas and root resorption using HE. The data were compared using two-way ANOVA, Tukey HSD, Games-Howell and chi-squared test, at the 5% significance level. It was observed a smaller number of osteoclasts and greater percentage of hyaline area in the EAZ group. There was no difference among the groups regarding bone remodeling, root resorption and tooth movement for all observed times.

Osteoprotegerin and zoledronate bone effects during orthodontic tooth movement

OBJECTIVES

To assess the effects of local delivery of recombinant fusion protein osteoprotegerin (OPG-Fc) and bisphosphonate zoledronate on bone and periodontal ligament in a rat tooth movement model.

MATERIALS AND METHODS

Maxillary first molars of 36 male Sprague-Dawley rats were displaced mesially using a calibrated spring connected to an anterior mini-screw. Two different drugs were used: a single dose of Zoledronate (16 μg) and a twice-weekly dose of OPG-Fc (5.0 mg/kg) were injected. Tooth movement was measured on scanned plaster casts. Structural and immunohistochemical analysis of the orthodontic-induced changes in bone included receptor activator of nuclear factor ĸ (RANK), Runx, type 1 collagen, matrix metalloproteinases (MMPs) 2 and 9, tissue inhibitors of metalloproteinases (TIMPs) 1 and 2, and vimentin.

RESULTS

Both groups showed a reduction in mesial molar displacement. Animals receiving OPG-Fc demonstrated only 52%, 31%, and 21% of the total mesial molar displacement compared to control rats at 7, 14, and 21 days, respectively (*p < 0.001). For rats receiving zoledronate tooth displacement decreased significantly with 52%, 46% and 30%, respectively (*p < 0.001). At 14 and 21 days, OPG-Fc group showed significantly less molar displacement than the zoledronate group (*p < 0.001). RANK, Runx, vimentin, MMP-9 and tissues-inhibitor metalloproteinase 1 immunoreactivity were reduced in zoledronate treated animals and even more in OPG treated animals.

CONCLUSION

Local delivery of OPG-Fc or zoledronate inhibits bone resorption and therefore tooth movement. OPG-Fc was more effective than zoledronate in blocking the action of osteoclasts.

Recombinant osteoprotegerin effects during orthodontic movement in a rat model

BACKGROUND AND OBJECTIVES

Anchorage is one of the most challenging sides in orthodontics. The use of biological modulators that inhibit osteoclasts could be a solution to address these problems and provide new adjunctive approaches. The aim of this study was to assess the effectiveness of recombinant osteoprotegerin fusion protein (OPG-Fc) in orthodontic anchorage.

MATERIALS AND METHODS

Two groups of male Sprague-Dawley rats were utilized. The animals in the experimental group received twice-weekly injections with high dose of OPG-Fc (5.0mg/kg) in mesial and distal mucosa of the first molars, and those in the control group received no drugs. Right first maxillary molars were mesialized using a calibrated nickel-titanium spring connected to an anterior mini-screw. Tooth movement was measured by two blinded observers using scanned and magnified stone casts. Receptor activator of nuclear factor κB (RANK), run-related transcription factor 2 (Runx2), type I collagen, vimentin, matrix metalloproteinases 2 and 9, S100 protein and the putative mechanoproteins acid-sensing ion channel (ASIC2) and transient receptor potential vainilloid 4 (TRPV4) were evaluated using immunohistochemistry.

RESULTS

OPG-Fc group showed an important decreased in mesial molar movement with only 52%, 31%, and 22% of the total mesial molar movement compared with control group at Days 7, 14, and 21, respectively (P < 0.001). RANK ligand and Runx2 positive cells were severely reduced after OPG-Fc treatment. Periodontal ligament architecture, cell arrangement, and immunohistochemical patter for vimentin, type I collagen and the mechanoproteins TRPV4 and ASIC2 were altered by tooth movement and all these parameters altered by the applied treatment.

CONCLUSIONS

OPG-Fc effectively inhibits osteoclastogenesis resulting in improved bone quantity and orthodontic anchorage. Based on present results, OPG-Fc could have clinical utility in preventing undesired tooth movements.

Effects of strontium ranelate on bone formation in the mid-palatal suture after rapid maxillary expansion

BACKGROUND

The aim of this experimental study was to investigate the effects of strontium ranelate on bone regeneration in the mid-palatal suture in response to rapid maxillary expansion (RME).

METHODS

Thirty-six male 6-week-old Wistar rats were randomly divided into three groups, ie, an expansion only (EO) group, an expansion plus strontium ranelate (SE) group, and a control group. An orthodontic appliance was set between the right and left upper molars of rats with an initial expansive force of 0.98 N. Rats in the SE group were administered strontium ranelate (600 mg/kg body weight) and then euthanized in batches on days 4, 7, and 10. Morphological changes in the mid-palatal suture were investigated using micro-computed tomography and hematoxylin and eosin staining after RME. Bone morphogenetic protein-2 expression in the suture was also examined to evaluate bone formation in the mid-palatal suture. Image-Pro Plus software was then used to determine the mean optical density of the immunohistochemical images. Analysis of variance was used for statistical evaluation at the P<0.05 level.

RESULTS

With expansive force, the mid-palatal suture was expanded, but there was no statistically significant difference (P>0.05) between the SE and EO groups. The bone volume of the suture decreased after RME, but was higher in the SE group than in the EO group on days 7 and 10. Further, expression of bone morphogenetic protein-2 in the SE group was higher than in the other two groups (P<0.05).

CONCLUSION

Strontium ranelate may hasten new bone formation in the expanded mid-palatal suture, which may be therapeutically beneficial in prevention of relapse and shortening the retention period after RME.

Effect of St John's wort on bone formation in the orthopaedically expanded premaxillary suture in rats: a histological study

BACKGROUND/OBJECTIVE

The aim of this study was to investigate the effect of systemic St John's wort (Hypericum perforatum) on bone formation in the expanded premaxillary suture in rats.

MATERIALS/METHODS

A total of 28 rats were randomly divided into four groups of equal numbers: control (C); only expansion (OE); St John's wort extract given only during the expansion and retention period (a total of 17 days; SJW group); and St John's wort extract given during the nursery phase before expansion (a period of 40 days), and during the expansion and retention periods (a total of 57 days; N + SJW group). After the 5 day expansion period was completed, the rats in the OE, SJW, and N + SJW groups underwent 12 days of mechanical retention, following which they were killed, and their premaxilla dissected and fixed. Histological examination was performed to determine the number of osteoclasts and capillaries, as well as the number of osteoblasts, inflammatory cell infiltration, and the amount of new bone formation.

RESULTS

Statistical analysis showed that the number of osteoclasts and capillaries, and the inflammatory cell infiltration, as well as new bone formation, were higher in the SJW and N + SJW groups than in the other groups. However, statistical analysis demonstrated that among these two groups, all parameters, with the exception of the number of capillaries, were higher in the N + SJW group than the SJW group.

CONCLUSIONS/IMPLICATIONS

Although more effective in long-term usage, systemic use of St John's wort hastens new bone regeneration at the premaxillary suture and may help prevent relapse after expansion.

Systemic propolis stimulates new bone formation at the expanded suture: a histomorphometric study

OBJECTIVE

To investigate the effects of systemically given propolis on the expanded premaxillary suture in a rat study model.

MATERIALS AND METHODS

The 24 rats were randomly divided into three groups-only expansion (OE), expansion plus propolis (PRO), and nonexpansion (control) groups. After the 5-day expansion period was completed, the OE and PRO groups underwent 12 days of mechanical retention. At the end of this period, the animals were euthanatized and their pre-maxillae were dissected and fixed. Histomorphometric examination was performed to determine the number of osteoclasts, osteoblasts, and capillaries as well as the intensity of inflammatory cells and amount of new bone formation.

RESULTS

Statistical analysis showed that the intensities of inflammatory cells, number of osteoblasts, and amount of new bone formation were greater in the PRO group than in the other groups. The PRO group also had more osteoclasts and new capillaries.

CONCLUSION

Systemic use of propolis may hasten new bone formation at the expanded suture in rats.