Effect of alendronate on the femoral metaphyseal defect under carbamazepine in ovariectomized rats

The Preventive Effect of Preoperative and Postoperative Selenium on the Medication-Related Osteonecrosis of the Jaw: An Animal Study in Rats

BACKGROUND

Medication-related osteonecrosis of the jaw (MRONJ) is a condition that can occur primarily in patients undergoing or have previously undergone therapy with bisphosphonates, particularly in the presence of risk factors, such as tooth extraction (TE).

PURPOSE

This study aimed to evaluate the effect of selenium (SEL) administration on the prevention of osteonecrosis of the jaw in an MRONJ animal model.

STUDY DESIGN, SETTING, AND SAMPLE

This study was a longitudinal in vivo animal study using a TE model in a sample of 48 Wistar rats.

PREDICTOR VARIABLE

The predictor variables were SEL exposure, timing of SEL exposure, and zoledronic acid (ZOL) exposure. The animals were randomly assigned to 4 treatment groups (n = 12 per group): 1) saline (negative control), 2) ZOL (positive control), 3) SELpreop + ZOL, and 4) ZOL + SELpostop. The animals were administered saline (negative control) or ZOL (0.06 mg/kg, intraperitoneally) once a week for 5 weeks. All rats underwent TE at the end of the fifth week. SEL (0.3 mg/kg, intraperitoneally) was administered once daily for 15 days to the SELpreop + ZOL group before TE and to the ZOL + SELpostop group after TE. All animals were sacrificed at the end of the ninth week.

MAIN OUTCOME VARIABLES

The primary outcome variables were new bone area, necrotic bone area, fibrosis, new connective tissue formation, and inflammatory cell infiltration in the histopathological analysis, as well as angiogenesis and percentage of osteoblasts in the immunohistochemical analysis.

COVARIATES

There was none.

ANALYSES

Statistical analysis was conducted using the Kruskal-Wallis test, followed by post hoc Bonferroni-corrected Mann-Whitney U tests, with a significance level of P ≤ .05.

RESULTS

The new bone area was higher in the ZOL + SELpostop group (3.00 score) than in the saline group (0.58 ± 1.08 score, P < .001) and the ZOL group (0.82 ± 1.40 score, P = .001), while the necrotic bone area was lower in the ZOL + SELpostop group (0.08 ± 0.29 score) than in the ZOL group (2.82 ± 0.40 score, P < .001) and the SELpreop + ZOL group (1.67 ± 0.89 score, P = .007). The percentage of osteoblasts was higher in the ZOL + SELpostop group (18.73%) than in the saline group (8.63%, P < .001) and the ZOL group (0.07%, P < .001), and it was also higher in the SELpreop + ZOL group (18.49%) than in the ZOL group (0.07%, P < .001).

CONCLUSION AND RELEVANCE

In conclusion SEL prevents MRONJ, with postoperative SEL demonstrating greater prevention effects. Given these findings, we hypothesize that SEL exposure may decrease the risk of MRONJ.

Trichostatin A enhances the titanium rods osseointegration in osteoporotic rats by the inhibition of oxidative stress through activating the AKT/Nrf2 pathway

The use of titanium implants as fixed supports following fractures in patients with OP can often result in sterile loosening and poor osseointegration. Oxidative stress has been shown to play a particularly important role in this process. While TSA has been reported to facilitate in vivo osteogenesis, the underlying mechanisms remain to be clarified. It also remains unclear whether TSA can improve the osseointegration of titanium implants. This study investigated whether TSA could enhance the osseointegration of titanium rods by activating AKT/Nrf2 pathway signaling, thereby suppressing oxidative stress. MC3T3-E1 cells treated with CCCP to induce oxidative stress served as an in vitro model, while an OVX-induced OP rat model was employed for in vivo analysis of titanium rod implantation. In vitro, TSA treatment of CCCP-treated MC3T3-E1 cells resulted in the upregulation of osteogenic proteins together with increased AKT, total Nrf2, nuclear Nrf2, HO-1, and NQO1 expression, enhanced mitochondrial functionality, and decreased oxidative damage. Notably, the PI3K/AKT inhibitor LY294002 reversed these effects. In vivo, TSA effectively enhanced the microstructural characteristics of distal femur trabecular bone, increased BMSCs mineralization capacity, promoted bone formation, and improved the binding of titanium implants to the surrounding tissue. Finally, our results showed that TSA could reverse oxidative stress-induced cell damage while promoting bone healing and improving titanium rods' osseointegration through AKT/Nrf2 pathway activation.

MiR-210 improves postmenopausal osteoporosis in ovariectomized rats through activating VEGF/Notch signaling pathway

BACKGROUND

To explore the effect and mechanism of action of miR-210 on postmenopausal osteoporosis (PMPO) in ovariectomized rats in vivo.

METHODS

An ovariectomized (OVX) rat model was established by ovariectomy. Tail vein injection was performed to overexpress and knock down miR-210 in OVX rats, followed by the collection of blood and femoral tissues from each group of rats. And quantitative real-time polymerase chain reaction (qRT-PCR) was applied to assess the expression level of miR-210 in femoral tissues of each group. Micro computed tomography (Micro CT) was adopted to scan the microstructure of the femoral trabecula in each group to obtain relevant data like bone mineral density (BMD), bone mineral content (BMC), trabecular bone volume fraction (BV/TV), trabecular thickness (Tb.Th), bone surface-to-volume ratio (BS/BV), and trabecular separation (Tb.Sp). ELISA was used for determining the level of bone alkaline phosphatase (BALP), amino-terminal propeptide of type I procollagen (PINP), osteocalcin (OCN), and C-terminal telopeptide of type I collagen (CTX-1) in serum; and Western blot for the protein level of Runt-related transcription factor 2 (Runx2), osteopontin (OPN), and collagen type I alpha 1 (COL1A1) in femoral tissues.

RESULTS

MiR-210 expression was significantly decreased in femoral tissues of OVX rats. Overexpression of miR-210 could obviously increase BMD, BMC, BV/TV and Tb.Th, whereas significantly decrease BS/BV and Tb.Sp in femurs of OVX rats. Moreover, miR-210 also downregulated BALP and CTX-1 level, upregulated PINP and OCN level in the serum of OVX rats promoted the expression of osteogenesis-related markers (Runx2, OPN and COL1A1) in the femur of OVX rats. Additionally, further pathway analysis revealed that high expression of miR-210 activated the vascular endothelial growth factor (VEGF)/Notch1 signaling pathway in the femur of OVX rats.

CONCLUSION

High expression of miR-210 may improve the micromorphology of bone tissue and modulate bone formation and resorption in OVX rats by activating the VEGF/Notch1 signaling pathway, thereby alleviating osteoporosis. Consequently, miR-210 can serve as a biomarker for the diagnosis and treatment of osteoporosis in postmenopausal rats.

Dual-crosslinked network of polyacrylamide-carboxymethylcellulose hydrogel promotes osteogenic differentiation in vitro

In our previous study, we successfully designed a dual-crosslinked network hydrogel by introducing the monomers acrylamide (AM), carboxymethylcellulose (CMC), zeolitic imidazolate framework-8 (ZIF-8), and alendronate (Aln). With the simultaneous presentation of physical and chemical crosslinks, the fabricated hydrogel with 10 % concentration of Aln@ZIF-8 (PAM-CMC-10%Aln@ZIF-8) exhibited excellent mechanical characteristics, high Aln loading efficiency (63.83 %), and a slow release period (6 d). These results demonstrate that PAM-CMC-10%Aln@ZIF-8 is a potential carrier for delaying Aln. In this study, we mainly focused on the biocompatibility and osteogenic ability of PAM-CMC-10%Aln@ZIF-8 in vitro, which is a continuation of our previous work. First, this study investigated the biocompatibility of dual-crosslinked hydrogels using calcein-AM/Propidium Iodide and cell counting kit-8. The morphology of rat bone mesenchymal stem cells was assessed using FITC-phalloidin/DAPI and vinculin immunostaining. Finally, osteogenic induction ability in vitro was assessed via alkaline phosphatase expression and alizarin red S staining, which was also confirmed using real-time PCR at the gene level and immunofluorescence at the protein level. The results indicated that the introduction of Aln enabled a dual-crosslinked hydrogel with superior biocompatibility and outstanding osteogenic differentiation ability in vitro, providing a solid foundation for subsequent animal experiments in vivo.

Daytime administration of melatonin has better protective effects on bone loss in ovariectomized rats

OBJECTIVE

To explore the difference in the protective effects of intraperitoneal injection of exogenous melatonin of daytime or nighttime on bone loss in ovariectomized (OVX) rats.

METHODS

After bilateral ovariectomy and sham surgery, 40 rats were randomly divided into four groups: sham operation group (Sham), ovariectomy (OVX), and daytime melatonin injection group (OVX + DMLT, 9:00, 30 mg/kg/d) and nighttime injection of melatonin (OVX + NMLT, 22:00, 30 mg/kg/d). After 12 weeks of treatment, the rats were sacrificed. The distal femur, blood and femoral marrow cavity contents were saved. The rest of the samples were tested by Micro-CT, histology, biomechanics and molecular biology. Blood was used for bone metabolism marker measurements. CCK-8, ROS, and Cell apoptosis are performed using MC3E3-T1 cells.

RESULTS

Compared with treatment at night, the bone mass of the OVX rats was significantly increased after the daytime administration. All microscopic parameters of trabecular bone increased, only Tb.Sp decreased. Histologically, the bone microarchitecture of the OVX + DMLT was also more dense than the bone microarchitecture of the OVX + LMLT. In the biomechanical experiment, the femur samples of the day treatment group were able to withstand greater loads and deformation. In molecular biology experiments, bone formation-related molecules increased, while bone resorption-related molecules decreased. After treatment with melatonin administration at night, the expression of MT-1β was significantly decreased. In cell experiments, the MC3E3-T1 cells treated with low-dose MLT had higher cell viability and greater efficiency in inhibiting ROS production than the MC3E3-T1 cells treated with high-dose MLT, which in turn more effectively inhibited apoptosis.

CONCLUSION

Daytime administration of melatonin acquires better protective effects on bone loss than night in OVX rats.

A biomimetic and bioactive scaffold with intelligently pulsatile teriparatide delivery for local and systemic osteoporosis regeneration

Osteoporosis is one of the most disabling consequences of aging, osteoporotic fractures and higher risk of the subsequent fractures leading to substantial disability and deaths, indicating both local fractures healing and the early anti-osteoporosis therapy are of great significance. Teriparatide is strong bone formation promoter effective in treating osteoporosis, while side effects limit clinical applications. Traditional drug delivery is lack of sensitive and short-term release, finding a new non-invasive and easily controllable drug delivery to not only repair the local fractures but also improve total bone mass has remained a great challenge. Thus, bioinspired by the natural bone components, we develop appropriate interactions between inorganic biological scaffolds and organic drug molecules, achieving both loaded with the teriparatide in the scaffold and capable of releasing on demand. Herein, biomimetic bone microstructure of mesoporous bioglass, a near-infrared ray triggered switch, thermosensitive liposomes based on a valve, and polydopamine coated as a heater is developed rationally for osteoporotic bone regeneration. Teriparatide is pulsatile released from intelligent delivery, not only rejuvenating osteoporotic bone defect, but also presenting strong systemic anti-osteoporosis therapy. This biomimetic bone carrying novel drug delivery platform is well worth expecting to be a new promising strategy and clinically commercialized to help patients survive from the osteoporotic fracture.

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A novel NIR-triggered three-in-one smart platform was proposed.

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Highly NIR-sensitive in vivo controlled release and self-regulating pulsatile release can be achieved.

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Local precise pulsatile release accelerates osteoporotic bone healing.

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This study focused on the osteoporotic bone regeneration of both skull and femur at the same time.

Bone development in offspring of pregnant rats treated with carbamazepine: Evaluation by three different methods

OBJECTIVE

This study was carried out to determine the effect of intrauterine carbamazepine (CBZ) exposure on fetal bone development during pregnancy.

METHODS

In the study, 24 female Wistar pregnant rats were used. Rats were 20 weeks old. They had an average body weight of 150-200 g. Pregnant rats were randomly selected and divided (n = 6) into a control group, low-dose CBZ (10 mg/kg/day) group, medium-dose CBZ (25 mg/kg/day) group, and high-dose CBZ (50 mg/kg/day) group. The ossification length (mm) and ossification area (mm² ) of the long bones of the fetuses in the experimental and control groups were calculated. The densities of alkaline phosphatase (AP) and tartrate-resistant acid phosphatase (TRAP) were analyzed. The ossification regions of the femurs of the fetuses were examined under a light microscope. Microstructural images of the femurs were evaluated with scanning electron microscope photographs. The densities of minerals involved in the ossification process were analyzed.

RESULTS

According to the results of the study, all three doses of CBZ caused loss of ossification areas, and it was observed that this bone loss also increased statistically significantly depending on the dose increase (p < .05). Calcium concentration decreased in the CBZ groups. When the electron microscope images were examined, it was determined that the cartilage matrix of the CBZ groups was thinned. In the histological evaluation of the groups, narrowing of the primary bone collar and smaller bone spicules in the ossification region compared to the control group were noted due to the increase in dose in the CBZ groups. In immunohistochemical staining, it was observed that the TRAP and AP expression values of the femurs were the lowest in the CBZ groups. These decreases were also statistically significant when compared with the control group.

SIGNIFICANCE

It was revealed with both microscopic and macroscopic findings that exposure to intrauterine CBZ negatively affected ossification and bone growth.

Experimental study on the effects of simvastatin in reversing the femoral metaphyseal defects induced by sodium valproate in normal and ovariectomized rats

Introduction

Long-term treatment with antiepileptic drugs may cause secondary osteoporosis. The present study investigated the influence of simvastatin (SIM) in reversing the effects of valproate on bone defect healing in normal and ovariectomized (OVX) rats.

Methods

Bone defects in femora were established in seven experimental groups of rats: control (vehicle), sodium valproate (SVP; 300 mg/kg/d), SVP plus SIM (25 mg/kg/d), sham control (sham), OVX, OVX SVP and OVX SVP plus SIM. All rats were euthanized at 8 weeks after bone defect creation.

Results

Micro-CT, biomechanical and histological evaluations demonstrated lower bone strength and delayed bone healing in the SVP therapy group compared with the SVP plus SIM therapy group. Biochemical and immunohistochemical results showed that osteocalcin (OCN), collagen I (Col I) and procollagen type I N-terminal propeptide (P1NP) levels decreased, tartrate-resistant acid phosphatase type 5 precursor (TRACP-5b) expression increased, and Dickkopf-1 (DKK-1) and receptor activator of nuclear factor-κ B ligand (RANKL) expression were upregulated in the SVP therapy rats compared with the SVP plus SIM therapy group. Bone loss was exacerbated by OVX, but the effect of SIM in ameliorating bone loss was also more marked in the OVX rats.

Conclusions

This study indicated lower bone strength and delayed healing of bone defects in rats given SVP therapy, especially the OVX SVP treatment group. In contrast, treatment with SIM was effective in enhancing bone strength and promoting bone defect repair and showed significant influence on promoting osteogenesis and inhibiting osteoclastogenesis.

Selenium-modified calcium phosphate cement can accelerate bone regeneration of osteoporotic bone defect

OBJECTIVE

The purpose is to observe whether local administration with selenium (Se) can enhance the efficacy of calcium phosphate cement (CPC) in the treatment of osteoporotic bone defects.

METHODS

Thirty ovariectomized (OVX) rats with two defects were generated and randomly allocated into the following graft study groups: (1) OVX group (n = 10), (2) CPC group (n = 10); and (3) Se-CPC group (n = 10). Then, these selenium-modified calcium phosphate cement (Se-CPC) scaffolds were implanted into the femoral epiphysis bone defect model of OVX rats for 12 weeks. Micro-CT, history, western blot and reverse transcription-quantitative polymerase chain reaction (RT-qPCR) analysis were used to observe the therapeutic effect and to explore the possible mechanism.

RESULT

Micro-CT and histological analysis evaluation showed that the Se-CPC group presented the strongest effect on bone regeneration and bone mineralization when compared with the CPC group and the OVX group. Protein expressions showed that the oxidative stress protein expressions, such as SOD2 and GPX1 of the Se-CPC group, are significantly higher than those of the OVX group and the CPC group, while Se-CPC remarkably reduced the expression of CAT. RT-qPCR analysis showed that the Se-CPC group displayed more OPG than the OVX and CPC groups (p < 0.05), while Se-CPC exhibited less RANKL than the OVX and CPC groups (p < 0.05).

CONCLUSION

Our current study demonstrated that Se-CPC is a scheme for rapid repair of femoral condylar defects, and these effects may be achieved by inhibiting local oxidative stress and through OPG/RANKL signaling pathway.

Intermittent administration sodium valproate has a protective effect on bone health in ovariectomized rats

The present work was aimed to evaluate the effect of different administration modes of sodium valproate (VPA) on bone strength, bone mass and bone mineral density in ovariectomized (OVX) rats and further investigation of the possible mechanism. 60 female SD rats were randomly divided into 4 groups: Sham group (Sham, n = 15), OVX group (OVX, n = 15), OVX rats received intermittent VPA treatment group (IVPA, n = 15) and OVX rats received daily VPA treatment group (EVPA, n = 15). After 12 weeks of treatment, the rats were sacrificed, and serum and femur samples were harvested. DEXA, Micro-CT, history, biomechanical testing, biochemical index and western blot analysis were used to observe the therapeutic effect and explore the possible mechanism. Micro-CT and DEXA analysis of bones revealed better BMD and higher BV/TV, Tb. Th, Tb. N, Conn. D and lower Tb. Sp at femoral metaphysis evaluated in IVPA when compared with OVX and EVPA group (P < 0.05). Histological, fluorescent analysis and biological strength revealed more trabecular bone and higher relative mineral apposition rate, maximal load, elastic modulus and energy at break with evaluated in IVPA when compared with OVX and EVPA group (P < 0.05). The levels of P1NP, estrogen, CTX, TRAP-5b and RANKL of the IVPA group showed a significant increase when compared with the OVX and EVPA group (P < 0.05). We confirm adverse effects on protein expressions including Notch1, Jagged1, HEY1, Wnt 1, β-catenin and RUNX2 following daily VPA treatment in OVX female rats. Our current study demonstrated that intermittent administration of sodium valproate has a protective effect on bone health in OVX rats and these effects may be achieved by activating Notch/Wnt/β-catenin/RUNX2 signal axis.