The effect of alendronate sodium on trabecular bone structure in an osteoporotic rat model

Evaluation of bone-protecting effects of palm carotene mixture in two- and three-dimensional osteoblast/osteoclast co-culture systems

Background: Carotene exists naturally in a complex mixture consisting of alpha (α), beta (β), and gamma (γ)-isoforms. Previous studies investigated the effects of individual carotene isomers on bone rather than their actions in a mixture. Purpose: This study explored the bone-protective properties of palm carotene mixture using both two- and three-dimensional co-culture systems. Study design: The viability of human foetal osteoblasts (hFOB 1.19), viability of human monocytic cell line (THP-1), osteoblast differentiation, osteoclast maturation, bone quality and strength were assessed in two- and three-dimensional co-culture system after treatment of palm carotene mixture. Methods: The viability of hFOB 1.19 and THP-1 was determined on day 1, 3, and 6 following treatment of palm carotene mixture. The osteoblast-osteoclast co-culture (ratio of hFOB 1.19 to THP-1 = 2:1) was treated with palm carotene mixture as well as subjected to alkaline phosphatase (ALP) and tartrate resistant acid phosphatase (TRAP) staining on day 21 to assess the osteoblast proliferation and osteoclast maturation. Dual-energy X-ray absorptiometry, micro-computed tomography, universal testing machine, and bone histomorphometry were used to assess the bone parameters of scaffolds co-cultured with osteoblasts and osteoclasts. Results: Palm carotene mixture (3.13 - 50 μg/mL) increased osteoblast viability. Monocyte viability decreased in lower concentration (3.13 - 12.5 μg/mL) but increased in higher concentration (25 - 50 μg/mL) of palm carotene mixture. Treatment with palm carotene mixture (12.5 µg/mL) demonstrated earlier peak for the ALP-positive area on day 14 but decreased total number of TRAP-positive multinucleated cells on day 21. Palm carotene mixture also increased bone volume and osteoblast number in the three-dimensional co-culture system. Conclusion: Palm carotene mixture potentially exhibits beneficial effects on bone by accelerating osteoblast proliferation and suppressing osteoclast maturation. The findings of current study serve as the basis for the further validation through animal experiments and human trials.

Inokosterone activates the BMP2 to promote the osteogenic differentiation of bone marrow mesenchymal stem cells and improve bone loss in ovariectomized rats

Evidence suggests that enhancing the osteogenic ability of bone marrow-derived mesenchymal stem cells (BMSCs) may be beneficial in the fight against osteoporosis (OP) effects. Inokosterone (IS) is a major active constituent of Achyranthis bidentatae radix (ABR), which stimulates osteogenic differentiation of mouse embryonic osteoblasts. This study aims to investigate effect of IS on OP using osteogenic differentiated BMSCs and ovariectomy (OVX)-induced OP rats. The BMSCs were treated with 50, 100, or 200 mg/L IS and OP rats were given 2 or 4 mg/kg of IS by gavage. Cell viability, the osteogenic differentiation marker protein expression level, and mineralization were observed. This study proved that IS improved cell viability, osteogenic differentiation, and cellular mineralization in BMSCs and raised expression levels of bone morphogenetic protein-2 (BMP2), Smad1, runt-related transcription factor 2 (RUNX2), collagen I, ALP, and OCN. By BMP2 knockdown/overexpression, this study also proved the BMP2 signaling pathway activation is a potential biological mechanism of IS to improve osteogenic differentiation and mineralization in osteogenic differentiated BMSCs. In OVX-induced OP rats, IS was observed to antagonize bone loss, improve osteogenic differentiation marker protein expression levels, and activate BMP-2, smad1, and RUNX2. These findings provide scientific support for further investigation of the biological mechanisms of IS in ameliorating OP.

Myricitrin: A promising herbal therapy for periodontitis in immunosuppressed status

Background

Periodontitis is a complex chronic inflammatory disease aggravated in immunosuppressed patients. However, adjuvant therapies can alleviate severe inflammation and slow down disease progression.

Objective

To evaluate the efficacy of myricitrin, a herbal flavonoid glycoside, in reducing immunosuppression-associated periodontitis and compare its effects with that of alendronate on alveolar bone regeneration.

Methods

Fifty albino Wistar rats were randomly allocated to the control, periodontitis, immunosuppressant, myricitrin, and alendronate groups. Ligature-associated periodontitis was induced in all groups, except the control group. Cyclosporin A (CsA) was administered subcutaneously in the immunosuppressant group for immunosuppression. The myricitrin group received CsA and myricitrin, whereas the alendronate group received CsA and alendronate. The therapeutic efficacies of myricitrin and alendronate were compared histologically, morphometrically, and biochemically.

Results

Myricitrin reversed bone destruction in the periodontitis and immunosuppressant groups. Morphometrically, myricitrin showed comparable improvements to alendronate in terms of gaining more bone area to 49.4 ± 4.6 and 59.5 ± 2%, respectively (P < 0.001 in relation to the untreated periodontitis group). Concomitantly, myricitrin increased osteoblast count significantly to 28.4 ± 4.7 closer to the 34.5 ± 2.4 count in the alendronate group (P < 0.001 compared with 22.5 ± 2.6 count of the immunosuppressant group). Moreover, myricitrin restored the serum calcium to 9.4 ± 0.6 mg/dL and alkaline phosphatase up to 112.9 ± 2.9 IU/L, which were almost normal levels similar to the control cohort (P > 0.05).

Conclusion

Myricitrin showed beneficial effects in counteracting bone resorption in subjects with immunosuppression-associated periodontitis. Its efficacy in slowing down disease progression was comparable to that of alendronate.

The potential anti-osteoporotic effect of exercise-induced increased preptin level in ovariectomized rats

Osteoporosis increases bone fragility and fractures. Preptin hormone is regulated by moderate exercise training and increases bone formation. Therefore, this study was conducted to see how estradiol administration and moderate exercise training affected osteoporotic changes in ovariectomized (OVX) rats. To achieve this aim, 36 healthy adult female Wistar albino rats were randomized into Sham, OVX, ovariectomized estradiol-treated (OVX + E) (OVX + E rats were treated using subcutaneous estradiol benzoate 2.5 μg/kg body weight/day), ovariectomized practicing moderate exercise training, ovariectomized estradiol-treated and practiced a moderate exercise training, and ovariectomized alendronate-treated (OVX + Alen) (OVX + Alen rats were treated orally with alendronate 3 mg/kg body weight/week) groups. Alendronate was used as a standard anti-osteoporotic drug. Moderate exercise training, including therapy with estradiol and alendronate for OVX rats began on the fourth week and lasted for six weeks. Results showed that OVX rats had estrogen and preptin deficiency in serum. These deficiencies were associated with a significant increase in bone resorption biomarkers (urinary deoxypyridinoline and hydroxyproline), and bone formation biomarkers (serum osteocalcin and bone-specific alkaline phosphatase). Also, serum pro-inflammatory cytokines (tumor necrosis factor alpha and interleukin-6) were increased, while bone osteopontin (OPN) expression was decreased. Subsequently, the osteoporotic alterations were verified based on histopathological changes. From the results, estradiol therapy and moderate exercise training significantly improved these findings to the same extent as that of the standard alendronate treatment. Therefore, through their anti-inflammatory properties, increasing bone OPN expression, and regulating serum preptin; estradiol therapy and moderate exercise training can reduce osteoporotic alterations in OVX rats. Thus, combined estradiol therapy and moderate exercise training could be a promising potential therapeutic protocol to reduce postmenopausal osteoporosis. Also, targeting serum preptin and bone osteopontin regulation could have a critical role in the treatment of postmenopausal osteoporosis.

Topical application of the plant extract SDTL-E in ovariectomized rats: A potential new approach for treating osteoporosis

Current osteoporosis medications have drawbacks of causing side effects and having slow onset, therefore developing osteoporosis drugs with faster onset and less side effects is essential. This study investigated the effects of the natural plant extract, SDTL-E, in ovariectomized (OVX)-induced osteoporosis rats. Rats were randomly assigned to sham operation control group (Control Group); OVX rat model group (Model Group) or OVX rat SDTL-E treatment group (SDTL-E Group). All groups underwent ovariectomy, but the Control Group did not have the ovaries removed. SDTL-E Group was treated with SDTL-E, Model and Control Groups were treated with vegetable oil, treatments were topically applied twice daily for 20 days. Results showed when compared with Model Group, SDTL-E Group significantly restored serum estradiol back to near Control Group level, serum ALP activity, serum and urinary calcium were significantly decreased, bone mechanics indicators increased and trabecular bone numbers slightly increased. These results demonstrated 20 days of SDTL-E topical treatment improved bone strength and trabecular bone structure in OVX-induced osteoporosis rats. The underlying mechanisms include restoring estradiol level, reducing bone turnover, net bone resorption, bone calcium loss, and calcium excretion through kidney. These findings suggest topical application of plant extract is a potential new approach with quick efficacy for treating osteoporosis.

Potential Role of Lycopene in the Prevention of Postmenopausal Bone Loss: Evidence from Molecular to Clinical Studies

Osteoporosis is a metabolic bone disease characterized by reduced bone mineral density, which affects the quality of life of the aging population. Furthermore, disruption of bone microarchitecture and the alteration of non-collagenous protein in bones lead to higher fracture risk. This is most common in postmenopausal women. Certain medications are being used for the treatment of osteoporosis; however, these may be accompanied by undesirable side effects. Phytochemicals from fruits and vegetables are a source of micronutrients for the maintenance of bone health. Among them, lycopene has recently been shown to have a potential protective effect against bone loss. Lycopene is a lipid-soluble carotenoid that exists in both all-trans and cis-configurations in nature. Tomato and tomato products are rich sources of lycopene. Several human epidemiological studies, supplemented by in vivo and in vitro studies, have shown decreased bone loss following the consumption of lycopene/tomato. However, there are still limited studies that have evaluated the effect of lycopene on the prevention of bone loss in postmenopausal women. Therefore, the aim of this review is to summarize the relevant literature on the potential impact of lycopene on postmenopausal bone loss with molecular and clinical evidence, including an overview of bone biology and the pathophysiology of osteoporosis.