Effect of resveratrol on the progression of experimental periodontitis in an ovariectomized rat model of osteoporosis: Morphometric, immune‐enzymatic, and gene expression analysis

β-Sitosterol inhibits osteoclast activity and reduces ovariectomy-induced bone loss by regulating the cAMP and NF-κB signaling pathways

BACKGROUND

β-Sitosterol, a prominent phytosterol present in numerous plant species, has been extensively studied for its potential health benefits, such as lipid-lowering, anxiolytic, and anti-inflammatory properties. Recently, the benefit of β-sitosterol on bone metabolism has been noted. The objective of the current study was to examine the impact of β-sitosterol on the skeletal system.

METHODS

Network pharmacology and molecular docking were used to predict how β-sitosterol may be used to treat osteoporosis. Cytotoxicity tests were conducted with different concentrations of β-sitosterol. The ability of β-sitosterol to inhibit osteoclast formation and function was evaluated, along with its potential molecular mechanism. An ovariectomized mouse model was used to assess the preventive effect of β-sitosterol on bone loss.

RESULTS

Network pharmacology analysis suggested that β-sitosterol could be a potential therapeutic treatment for osteoporosis by regulating the cAMP signaling pathway. β-sitosterol dose-dependently inhibited osteoclast differentiation and function without obvious cytotoxicity. Specifically, 20 μM β-sitosterol could obviously repress the number and size of osteoclasts, decrease the formation of F-actin belts, and reduce the bone-resorbing activity of osteoclasts. Some key signaling mediators, including PKA, c-Jun, NFATc1, p-CREB, and NF-κB, were downregulated by β-sitosterol. β-sitosterol acted by attenuating the cAMP and NF-κB signaling pathways. In vivo experiments confirmed β-sitosterol protected ovariectomy-induced bone loss though suppressing osteoclastic bone resorption.

CONCLUSION

β-sitosterol could inhibit the production and function of osteoclasts in vitro and reverse ovariectomy-induced bone loss. Thus, β-sitosterol could be a potential supplement for diseases with active bone resorption such as osteoporosis.

Impact of Wine Polyphenols on the Inflammatory Profile of Induced Apical Periodontitis in Rats

INTRODUCTION

This study evaluated the impact of dealcoholized red wine polyphenols on the inflammation and lesion volume associated with apical periodontitis (AP) in rats.

METHODS

Thirty-two Wistar rats receiving AP induction were arranged as follows: Control Group, Dealcoholized Red Wine Group (DRW), Red Wine Group, and Alcohol Group (ALC). Solutions were administered daily in a volume of 4.28 mL/kg via gavage for 45 days. Mandibles and maxillae were removed for histologic, immunohistochemical (IL-1β, IL-10, tumor necrosis factor-alpha, receptor activator of nuclear factor κB ligand, osteoprotegerin [OPG], and tartrate-resistant acid phosphatase), and micro-computed tomography analyses of the AP site. A statistical analysis was performed with a significance level of 5%.

RESULTS

Inflammation and TRAP-positive cell count were similar for DRW and Red Wine Group, but lower when compared to Control Group and ALC (P < .001). The immunohistochemical expression of OPG was higher for DRW than for ALC (P < .05). A larger lesion volume was observed in ALC compared to other groups (P < .001).

CONCLUSIONS

Prophylactic administration of dealcoholized red wine significantly reduced inflammation, decreased the number of TRAP-positive cells, enhanced OPG expression, and reduced lesion volume compared to water and alcohol solutions.

Omega-3 attenuates the severity of medication-related osteonecrosis of the jaws in rats treated with zoledronate

This study aimed to evaluate the ability of ω-3 to modulate the tissue response in rats with MRONJ, focusing on histopathological and immunohistochemical parameters. Forty Wistar rats were subjected to bilateral ovariectomy and, three months later, the medication regimen with ZOL (100μg/kg; groups ZOL and ZOL-ω3) of vehicle (VEH and VEH-ω3) was initiated. Following 3 weeks of ZOL or VEH, experimental periodontitis was induced around the mandibular left first molars of all animals. Then, 14 days later (one day before tooth extraction), daily dietary supplementation with ω-3 was given to animals belonging to groups VEH-ω3 or ZOL-ω3. Euthanasia was performed 21 days after tooth extraction. Histologic, histometric (newly-formed bone tissue [NFBT] and non-vital bone tissue [NVBT]), and immunohistochemical (TNF-α, α-SMA, ALP, IL-1β, VEGF, OCN, and TRAP) analyses were performed. Dietary supplementation with ω-3 reduced the amount of NVBT and controlled the intensity and extension of the inflammatory infiltrate in ZOL-ω3, as compared with ZOL. Osteoclast and osteoblast activity were not statistically different between groups ZOL and ZOL-ω3. The structure of the epithelium and the underlining connective tissue were improved by the supplementation with ω-3 in animals under ZOL therapy. Oral supplementation with omega-3 controlled the inflammation and reduced the amount of non-vital bone at the tooth extraction site of ovariectomized rats treated with ZOL and attenuating the severity of MRONJ.

Jaw osteoporosis: Challenges to oral health and emerging perspectives of treatment

Osteoporosis is a prevalent bone metabolic disease that poses a significant challenge to global human health. Jaw osteoporosis, characterized by microstructural damage of the jaw resulting from various factors, is one of the common manifestations of this condition. Recent studies have demonstrated that jaw osteoporosis has multifaceted effects on oral health and can negatively impact conditions such as periodontitis, oral implantation, orthodontic treatment, and wound healing. However, there are still some limitations in the conventional treatment of osteoporosis. For instance, while bisphosphonates can enhance bone quality, they may also lead to osteonecrosis of the jaw, which poses a potential safety hazard in oral diagnosis and treatment. In recent years, considerable attention has been focused on improving the pathological condition of jaw osteoporosis. Treatment strategies such as gut microbial regulation, extracellular vesicles, molecular targeted therapy, herbal medicine, mechanical stimulation are expected to enhance efficacy and minimize adverse reactions. Therefore, understanding these effects and exploring novel treatments for jaw osteoporosis may provide new insights for oral health maintenance and disease treatment. This article reviews the impact of jaw osteoporosis on oral health and describes the limitations associated with current methods. It also discusses emerging perspectives on treatment, offering a comprehensive overview of the challenges and future directions in managing jaw osteoporosis.

Resveratrol for preventing medication-related osteonecrosis of the jaws in rats

This study evaluated the effect of resveratrol (RES) on the prevention of medication-related osteonecrosis of the jaws (MRONJ) in ovariectomized (OVX) rats treated with zoledronate (ZOL). Fifty rats were distributed in five groups: SHAM (n = 10): non-ovariectomy + placebo; OVX (n = 10):ovariectomy + placebo; OVX + RES (n = 10):ovariectomy + resveratrol; OVX + ZOL (n = 10):ovariectomy + placebo + zoledronate; and OVX + RES + ZOL (n = 10):ovariectomy + resveratrol + zoledronate. The mandibles left sides were analyzed with micro-CT, histomorphometry, and immunohistochemistry. On the right side, bone markers gene expression was analyzed by qPCR. ZOL increased the percentage of necrotic bone and reduced the neo-formed bone compared to groups not receiving ZOL (p < 0.05). RES impacted the tissue healing pattern in OVX + ZOL + RES, reduced inflammatory cell infiltrate, and improved bone formation in the extraction site. Osteoblasts, alkaline phosphatase (ALP)-, and osteocalcin (OCN)-immunoreactive cells were lower in OVX-ZOL than in SHAM, OVX, and OVX-RES. The OXV-ZOL-RES had fewer osteoblasts and ALP- and OCN-cells than the SHAM and OVX-RES. The tartrate-resistant acid phosphatase (TRAP)-positive cells were reduced in the presence of ZOL (p < 0.05), while the TRAP mRNA levels increased with ZOL treatment, with or without resveratrol, compared with the other groups (p < 0.05). RES alone increased superoxide dismutase levels compared to OVX + ZOL and OVX + ZOL + RES (p < 0.05). In conclusion, resveratrol reduced the tissue impairment severity induced by ZOL; however, it could not prevent the occurrence of MRONJ.

Antioxidant, anti-inflammatory and antimicrobial activity of natural products in periodontal disease: a comprehensive review

Periodontal diseases (PD) are common chronic inflammatory oral pathologies that are strongly linked to others not found in the mouth cavity. The immune system mediates the host response, which includes the upregulation of proinflammatory cytokines, metalloproteinases, and reactive oxygen species (ROS); the latter may play an important role in the establishment and progression of inflammatory diseases, particularly periodontal disease, via the development of oxidative stress (OS). Natural antioxidants have powerful anti-inflammatory properties, and some can reduce serum levels of key PD indicators such tumor necrosis factor (TNF) and interleukin IL-1. This review compiles, through a thorough literature analysis, the antioxidant, anti-inflammatory, and antibacterial effects of a variety of natural products, as well as their therapeutic potential in the treatment of PD.

Establishment and assessment of rodent models of medication-related osteonecrosis of the jaw (MRONJ)

Medication-related osteonecrosis of the jaw (MRONJ) is primarily associated with administering antiresorptive or antiangiogenic drugs. Despite significant research on MRONJ, its pathogenesis and effective treatments are still not fully understood. Animal models can be used to simulate the pathophysiological features of MRONJ, serving as standardized in vivo experimental platforms to explore the pathogenesis and therapies of MRONJ. Rodent models exhibit excellent effectiveness and high reproducibility in mimicking human MRONJ, but classical methods cannot achieve a complete replica of the pathogenesis of MRONJ. Modified rodent models have been reported with improvements for better mimicking of MRONJ onset in clinic. This review summarizes representative classical and modified rodent models of MRONJ created through various combinations of systemic drug induction and local stimulation and discusses their effectiveness and efficiency. Currently, there is a lack of a unified assessment system for MRONJ models, which hinders a standard definition of MRONJ-like lesions in rodents. Therefore, this review comprehensively summarizes assessment systems based on published peer-review articles, including new approaches in gross observation, histological assessments, radiographic assessments, and serological assessments. This review can serve as a reference for model establishment and evaluation in future preclinical studies on MRONJ.

Anti-Osteoporotic Mechanisms of Polyphenols Elucidated Based on In Vivo Studies Using Ovariectomized Animals

Polyphenols are widely known for their antioxidant activity, i.e., they have the ability to suppress oxidative stress, and this behavior is mediated by the autoxidation of their phenolic hydroxyl groups. Postmenopausal osteoporosis is a common health problem that is associated with estrogen deficiency. Since oxidative stress is thought to play a key role in the onset and progression of osteoporosis, it is expected that polyphenols can serve as a safe and suitable treatment in this regard. Therefore, in this review, we aimed to elucidate the anti-osteoporotic mechanisms of polyphenols reported by in vivo studies involving the use of ovariectomized animals. We categorized the polyphenols as resveratrol, purified polyphenols other than resveratrol, or polyphenol-rich substances or extracts. Literature data indicated that resveratrol activates sirtuin 1, and thereafter, suppresses osteoclastogenic pathways, such as the receptor activator of the nuclear factor kappa B (RANK) ligand (RANKL) pathway, and promotes osteoblastogenic pathways, such as the wingless-related MMTV integration site pathway. Further, we noted that purified polyphenols and polyphenol-rich substances or extracts exert anti-inflammatory and/or antioxidative effects, which inhibit RANKL/RANK binding via the NF-κB pathway, resulting in the suppression of osteoclastogenesis. In conclusion, antioxidative and anti-inflammatory polyphenols, including resveratrol, can be safe and effective for the treatment of postmenopausal osteoporosis based on their ability to regulate the imbalance between bone formation and resorption.

Preclinical models of medication-related osteonecrosis of the jaw (MRONJ)

Medication-related osteonecrosis of the jaw (MRONJ) is a potentially severe adverse event affecting patients with cancer and patients with osteoporosis who have been treated with powerful antiresorptives (pARs) or angiogenesis inhibitors (AgIs). pARs, including nitrogen-containing bisphosphonates (N-BPs; e.g., zoledronic acid, alendronate) and anti-RANKL antibodies (e.g., denosumab), are used to manage bone metastases in patients with cancer or to prevent fragility fractures in patients with osteoporosis. Though significant advances have been made in understanding MRONJ, its pathophysiology is still not fully elucidated. Multiple species have been used in preclinical MRONJ research, including the rat, mouse, rice rat, rabbit, dog, sheep, and pig. Animal research has contributed immensely to advancing the MRONJ field, particularly, but not limited to, in developing models and investigating risk factors that were first observed in humans. MRONJ models have been developed using clinically relevant doses of systemic risk factors, like N-BPs, anti-RANKL antibodies, or AgIs. Specific local oral risk factors first noted in humans, including tooth extraction and inflammatory dental disease (e.g., periodontitis, periapical infection, etc.), were then added. Research in rodents, particularly the rat, and, to some extent, the mouse, across multiple laboratories, has contributed to establishing multiple relevant and complementary preclinical models. Models in larger species produced accurate clinical and histopathologic outcomes suggesting a potential role for confirming specific crucial findings from rodent research. We view the current state of animal models for MRONJ as good. The rodent models are now reliable enough to produce large numbers of MRONJ cases that could be applied in experiments testing treatment modalities. The course of MRONJ, including stage 0 MRONJ, is characterized well enough that basic studies of the molecular or enzyme-level findings in different MRONJ stages are possible. This review provides a current overview of the existing models of MRONJ, their more significant features and findings, and important instances of their application in preclinical research.

Effect of zoledronic acid on bone nanocomposites organization and prevention of bone mineral density loss in ovariectomized rats

OBJECTIVES

Osteoporosis often occurs in individuals of different age groups, frequently during menopause and after ovariectomy. It increases the risk of pathological fractures almost twice. The aim of our research was to assess bone metabolism, nanocomposite structure of the tibia under conditions of ovariectomy and zoledronic acid treatment.

METHODS

X-ray diffraction has been performed for nanostructure analysis of mineral crystallites and crystal lattice of hydroxyapatite in the tibia samples of ovariectomized rats with additional application of bisphosphonate zoledronic acid (0.025 mg/kg). Markers of remodeling - osteocalcin, alkaline phosphatase, tartrate resistant acid phosphatase 5b - were determined. Quantitative amount of calcium in the bones was detected by atomic absorption method.

RESULTS

Zoledronic acid prevented loss of mineral mass after ovariectomy. Rats after ovariectomy, treated with zoledronic acid, showed statistically higher (р<0.05) values of crystalline phase and calcium content compared with the SHAM-surgery and ovariectomy groups (р<0.05). Zoledronic acid inhibited bone remodeling, which is proved by tartrate resistant acid phosphatase 5b reduction and inhibition of osteoclasts during the experiment.

CONCLUSIONS

These results enable to suggest that zoledronic acid can improve mineral mass of the bone during menopause in individuals of different age groups.