Influence of prednisolone-induced osteoporosis on bone mass and bone quality of the mandible in rats

The combination of olive oil and Lepidium sativum improves the deleterious effects resulting from dexamethasone-induced osteoporosis in rats

Introduction

Osteoporosis is characterized by deterioration of bone microarchitecture and reduced bone mass and can increase the risk of fracture. To reduce this risk, the aim of this study was to compare the combination effects of olive oil and Lepidium sativum compared to the conventional drug therapy alendronate.

Methods

Osteoporosed-induced rat model was established by administration of dexamethasone in female adult albino rats. The serum level of Ca2+, P3+, and osteocalcin was assessed. In addition, histopathological changes and immunohistochemical expression of osteopontin within bone specimens were performed.

Results

Our results showed that a combination of olive oil and Lepidium sativum had a beneficial therapeutic effect in the treatment of osteoporosis as compared to alendronate therapy. This was demonstrated by increase of serum Ca2+, P3+, and osteocalcin levels in treated compared to control groups. Intriguingly, the highest effect was noticed in rats that received a combination of olive oil and Lepidium sativum compared to the individual treatment. This was reflected by an increase in the cortical bone thickness and a decrease in immunohistochemical expression of osteopontin compared to individual treated groups.

Conclusion

We concluded that the administration of a combination of olive oil and Lepidium sativum improves bone mineral health and intensity and reduces the risk of osteoporosis in a rat model.

Fractal properties and radiomorphometric indices of the trabecular structure of the mandible in patients using systemic glucocorticoids

OBJECTIVES

The aim of this study is to evaluate the mandibular trabecular and cortical bone structure of patients using systemic glucocorticoid (GC) and compare to control group with the fractal analysis (FA) and radiomorphometric indices.

METHODS

Two researchers retrospectively investigated 192 dental panoramic radiographs to compare individuals using systemic GCs to healthy controls. FA was performed in 4 different regions; geometrical center of the mandibular ramus (ROI1), cancellous bone on supracortical mandibular angle area inferior to the mandibular canal (ROI2), cancellous bone on mesial to the mental foramen (ROI3), basal cortical bone extending mental foramen to the first molars' distal root in the mandibular corpus (ROI4). Panoramic mandibular index (PMI), mandibular cortical width (MCW) and mandibular cortical index (MCI) were performed for evaluate cortical thickness and porosity. The Shapiro-Wilk test was used to determine the normal distribution of the data, the independent t test for comparison of values and the chi-square test for descriptive statistics.

RESULTS

There were statistically significant differences in ROI4 and MCW. The fractal dimension (FD) values in ROI4 and MCW were significantly lower in study group. There were no significant differences in FD values in ROI1, ROI2, ROI3 and PMI and MCI measurements between both groups.

CONCLUSIONS

FA and radiomorphometric measurements is an efficient method to detect early changes in bone mass. In our study, ROI4 and MCW were significantly lower in study group. Osteoporosis prevention should be considered in patients using systemic GCs.

Glucocorticoids cause mandibular bone fragility and suppress osteocyte perilacunar-canalicular remodeling

Osteocytes support dynamic, cell-intrinsic resorption and deposition of bone matrix through a process called perilacunar/canalicular remodeling (PLR). In long bones, PLR depends on MMP13 and is tightly regulated by PTH, sclerostin, TGFβ, and glucocorticoids. However, PLR is regulated differently in the cochlea, suggesting a mechanism that is anatomically distinct. Unlike long bones, the mandible derives from neural crest and exhibits unique susceptibility to medication and radiation induced osteonecrosis. Therefore, we sought to determine if PLR in the mandible is suppressed by glucocorticoids, as it is in long bone. Hemimandibles were collected from mice subcutaneously implanted with prednisolone or vehicle containing pellets for 7, 21, or 55 days (n = 8/group) for radiographic and histological analyses. Within 21 days, micro-computed tomography revealed a glucocorticoid-dependent reduction in bone volume/total volume and trabecular thickness and a significant decrease in bone mineral density after 55 days. Within 7 days, glucocorticoids strongly and persistently repressed osteocytic expression of the key PLR enzyme MMP13 in both trabecular and cortical bone of the mandible. Cathepsin K expression was significantly reduced only after 55 days of glucocorticoid treatment, at which point histological analysis revealed a glucocorticoid-dependent reduction in the lacunocanalicular surface area. In addition to reducing bone mass and suppressing PLR, glucocorticoids also reduced the stiffness of mandibular bone in flexural tests. Thus, osteocyte PLR in the neural crest-derived mandible is susceptible to glucocorticoids, just as it is in the mesodermally-derived femur, highlighting the need to further study PLR as a target of drugs, and radiation in mandibular osteonecrosis.

Progress in TiO2 nanotube coatings for biomedical applications: a review

Titanium dioxide nanotubes (TNTs) have drawn wide attention and been extensively applied in the field of biomedicine, due to their large specific surface area, good corrosion resistance, excellent biocompatibility, and enhanced bioactivity. This review describes the preparation of TNTs and the surface modification that entrust the nanotubes with better antibacterial property and enhanced osteoblast adhesion, proliferation, and differentiation. Considering the contact between TNTs' surface and surrounding tissues after implantation, the interactions between TNTs (with properties including their diameter, length, wettability, and crystalline phase) and proteins, platelets, bacteria, and cells are illustrated. The state of the art in the applications of TNTs in dentistry, orthopedic implants, and cardiovascular stents are introduced. In particular, the application of TNTs in biosensing has attracted much attention due to its ability for the rapid diagnosis of diseases. Finally, the difficulties and challenges in the practical application of TNTs are also discussed.

Micro-CT analysis of the rodent jaw bone micro-architecture: A systematic review

Introduction

Knowledge about macro- and micro-structural characteristics may improve in vivo estimation of the quality and quantity of regenerated bone tissue. For this reason, micro-CT imaging has been applied to evaluate alveolar bone remodelling, alterations of periodontal ligament thickness and cortical and trabecular bone changes in rodent jaw bones. In this paper, we provide a systematic review on the available micro-CT literature on jaw bone micro-architecture.

Methodology

A detailed search through the PubMed database was performed. Articles published up to December 2013 and related to maxilla, mandible and condyle with quantitatively analysed bone micro-architectural parameters were considered eligible for inclusion. Two reviewers assessed the search results according to inclusion criteria designed to identify animal studies quantifying the bone micro-architecture of the jaw rodent bones in physiological or drug-induced disease status, or in response to interventions such as mechanical loading, hormonal treatment and other metabolic alterations. Finally, the reporting quality of the included publications was evaluated using the tailored ARRIVE guidelines outlined by Vignoletti and Abrahamsson (2012).

Results

Database search, additional manual searching and assessment of the inclusion and exclusion criteria retrieved 127 potentially relevant articles. Eventually, 14 maxilla, 20 mandible and 12 condyle articles with focus on bone healing were retained, and were analysed together with 3 methodological papers. Each study was described systematically in terms of subject, experimental intervention, follow-up period, selected region of interest used in the micro-CT analysis, parameters quantified, micro-CT scanner device and software. The evidence level evaluated by the ARRIVE guidelines showed high mean scores (between 18 and 25; range: 0–25), indicating that most of the selected studies are well-reported. The major obstacles identified were related to sample size calculation, absence of adverse event descriptions, randomization or blinding procedures.

Conclusions

The evaluated studies are highly heterogeneous in terms of research topic and the different regions of interest. These results illustrate the need for a standardized methodology in micro-CT analysis. While the analysed studies do well according to the ARRIVE guidelines, the micro-CT procedure is often insufficiently described. Therefore we recommend to extend the ARRIVE guidelines for micro-CT studies.

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This review investigates discrepancies between reports using micro-CT imaging of rodent jaw bone, the applied methodology and reported results.

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Knowledge about the bone micro-architecture of the rodent jaw is scarce.

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Jaw bone micro-architecture varies according to ROI selections and the methodology applied to define a specific region are insufficient.

Glucocorticoids reduce alveolar and trabecular bone in mice

Glucocorticoid (GC) treatment is the main cause of secondary osteoporosis. There are some controversies about the relationships between alveolar bone loss and bone loss at the appendicular and axial skeleton.

OBJECTIVE

To assess, in parallel, the effects of GCs on alveolar bone and on the tibia in a mice model.

METHODS

Five-month-old male Swiss-Webster mice were randomized into two groups. Pellets releasing 5 mg/kg/day of prednisolone or control pellets were subcutaneously implanted for 28 days. After euthanasia, the right tibia and the right hemimandible of each mouse were analyzed by histomorphometry and microcomputed tomography. Alveolar bone consists of a thin slab between the incisor and the molar roots connected with the alveolar processes. A 2D-frontal section was done through the pulp chamber of the first molar and was used to measure the thickness of the alveolar bone slab. A 2D-sagittal section was done through the pulp chamber of the three molars and was used to measure bone volume in the alveolar processes.

RESULTS

At day 28, thickness and bone volume of alveolar bone were significantly decreased in the GC group (P<0.05). At the tibia, GCs decreased bone formation with a reduced mineral apposition rate and bone formation rate and a significant decrease in BV/TV and Tb.Th (P<0.05).

CONCLUSION

Although the amount of alveolar bone is very low in the mouse, this study shows that GCs can induce an alveolar bone loss in long-term treated animals.