Protective effects of low-magnitude high-frequency vibration on high glucose-induced osteoblast dysfunction and bone loss in diabetic rats

Frequency-Regulated Repeated Micro-Vibration Promotes Osteoblast Differentiation Through BMP Signaling in MC3T3-E1 Cells

Physical stimulation, which is a key factor affecting the metabolism of osteoblasts and their precursor cells, plays an important role in bone remodeling; however, the role of micro-vibrations in osteoblast differentiation is unclear. In the present study, we determined the effects of frequency-regulated repeated micro-vibration (FRMV) on cell proliferation and established a method to induce osteoblast differentiation through FRMV using the mouse pre-osteoblast-like cell line MC3T3-E1, which is widely used in bone metabolism research. The results indicated that FRMV significantly influenced the proliferation of MC3T3-E1 cells in a normal growth medium. FRMV at 42.2 Hz significantly promoted proliferation, whereas FRMV at 92.1 Hz showed no effect on the proliferation rate. Moreover, FRMV at 42.2 Hz significantly increased alkaline phosphatase (ALP) enzyme activity and ALP gene expression in MC3T3-E1 cells. Treatment with LDN193189, a bone morphogenetic protein (BMP) signaling inhibitor, revealed that the FRMV-induced upregulation in ALP enzyme activity and ALP gene expression were significantly suppressed in MC3T3-E1 cells. The results suggest that the FRMV protocol developed in the present study induces osteoblast differentiation through the BMP signaling pathway. Thus, FRMV may contribute to the development of effective bone regeneration technologies.

Dissecting the mechanisms of velvet antler extract against diabetic osteoporosis via network pharmacology and proteomics

ETHNOPHARMACOLOGICAL RELEVANCE

Velvet antler (VAE) is a famous traditional Chinese medicine (TCM), which has been used for thousands of years to treat bone-related diseases. Nonetheless, whether VAE has anti-diabetic osteoporosis (DOP) properties remains to be elucidated.

AIM OF THE STUDY

The therapeutic mechanism of VAE on DOP is based on integrated proteomics of network pharmacology strategies to study related targets and pathways.

MATERIALS AND METHODS

Liquid chromatography-mass spectrometry (LC/MS) was used to analyze the main molecular components present in the VAE. The DOP mouse model was created by combining a high-fat diet with streptozotocin (STZ). High glucose (HG) induced MC3T3-E1 cells were used as a cell model to evaluate the therapeutic effect of VAE. The mechanisms of VAE in treating DOP were predicted through proteomics. Molecular docking, molecular dynamics simulations, DARTS and functional experiments were employed to further verify its mechanisms.

RESULTS

Altogether 30 components were identified by LC-MS. In vitro and in vivo results were confirmed that VAE had a protective effect on DOP. Combined with network pharmacology, proteomics and functional experiments revealed that TNF/PI3K-AKT signaling pathway may be the potential biochemical pathway for VAE in treating DOP.

CONCLUSIONS

The innovation of this study was investigating the effectiveness of VAE in treating DOP in vivo and in vitro and suggested that VAE might exert anti-DOP effects through the TNF/PI3K-AKT signaling pathway by network pharmacology and proteomics and found that ATK1 was the core target of VAE, which provided valuable insights for the clinical application of VAE in DOP.

Low-magnitude high-frequency vibration ameliorates high glucose-induced endothelial injury by restoring mitochondrial function via AMPK/mTOR pathway

High glucose-induced dysfunction of endothelial cells is a critical and initiating factor in the genesis of diabetic vascular complications. Low-magnitude high-frequency vibration (LMHFV) is a non-invasive biophysical intervention. It has been reported that it exhibits protective effects on high glucose-induced osteoblast dysfunction, but little was known on diabetic vascular complications. In this work, we aim to clarify the role of LMHFV on high glucose-induced endothelial dysfunction and hypothesized that the protective effects functioned through adenosine monophosphate-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR) pathway. We cultured primary murine aortic endothelial cells (MAECs) in normal or HG medium, respectively, before exposing to LMHFV. The tube formation, paracellular permeability assay, and aortic ring sprouting assay showed that the high glucose injured-function of MAECs was improved after LMHFV treatment. The intracellular ROS generation analysis, mitochondrial complex I activities measurement, ATP measurement and mitochondrial membrane potential (MMP), and mitochondrial ROS generation analysis of MAECs indicated that mitochondrial function was restored by LMHFV loading in a high glucose environment. Mechanically, western blot assays showed that AMPK phosphorylation was promoted and mTOR was inhibited in LMHFV-induced endothelial function restoration. After the administration of the AMPK inhibitor, Compound C, these protective effects resulting from LMHFV are reversed. These findings suggest that LMHFV plays a significant role in protecting endothelial cells' function and mitochondrial function in high glucose-induced injured MAECs via AMPK/mTOR signalling.

Do Vibrational Forces Induce an Anabolic Effect in the Alveolar Bone of Animal Models? A Systematic Review

Mechanical vibrations have a biphasic effect depending on the context in which they are applied; their anabolic action has been used in medicine to increase bone density. In dental specialties such as orthodontics, their catabolic effect during mechanical compression has been widely studied, but the anabolic effect of vibrations is less investigated, so it is important to carry out research to clarify the effect of vibrations on the alveolar bone, explore a new approach to its use in orthodontics, and the increase of post-treatment bone density to prevent relapse. Hence, this work aims to systematically review the literature to evaluate the evidence regarding vibratory stimulation and its anabolic effects on alveolar bone in animal models. Methodology: A systematic review followed the PRISMA guidelines in PubMed, Scopus, and Web of Science databases. With the PICO strategy, we formulate the subsequent research question: Does the application of vibrational force induce an anabolic effect in the alveolar bone of animal models? Due to the lack of human studies, the population of interest was animal models; only articles where mechanical vibrations were the intervention method and the alveolar bone density or osteogenesis were evaluated and included. The selected studies underwent quality and risk of bias assessment through ARRIVE and SYCRLE instruments, respectively. This protocol was registered in INPLASY, under ID number: 202280103. Results: All eight articles included in this work demonstrate that applying low and high frequency vibrations increases the osteogenic effect by increasing the density and volume of bone tissue and increasing the expression of osteogenic markers. The included studies present a medium quality and risk of bias. Conclusion: It is important to highlight that, regardless of the protocol used, low or high frequency vibrations increase bone density, particularly in the alveolar bone, since this is the bone of interest in orthodontics. These promising results set an important precedent for the design of experimental protocols but now in the context of post-orthodontic treatment in humans.

Prevention of bone deterioration by whole-body vibration in a rat model of pre-type 2 diabetes

OBJECTIVES

To examine effects of whole-body vibration (WBV) on bone properties in pre-type 2 diabetes mellitus (T2DM) rats.

METHODS

Six-week-old male Hos:ZFDM-Lepr fa, fa/fa (DM) and Hos:ZFDM-Leprfa,fa/+ (CON; untreated non-DM) rats were used in the experiments. Half of DM rats were subjected to WBV (45 Hz, 0.5 g, 15 min/day, 5 days/week) for 8 weeks (WBV group), and the other half was not (DM group).

RESULTS

Bone mass, trabecular bone microstructure (TBMS), and cortical bone geometry (CBG) parameters were worse in the DM and WBV groups compared with the CON group. Maximum load was significantly decreased in the DM group compared with the CON group, and the break point was significantly higher in the WBV group compared with the DM group. Serum levels of bone specific alkaline phosphatase were significantly lower in the WBV group compared with the CON group. Glycemic control was not worse in the WBV group compared with the DM group, but not the same levels as the CON group.

CONCLUSIONS

These findings suggest that WBV can potentially delay the decrease in maximum load, although it does not prevent the deterioration of bone mass, TBMS, and CBG parameters.

Selenium nanoparticles stimulate osteoblast differentiation via BMP-2/MAPKs/β-catenin pathway in diabetic osteoporosis

Aim: To evaluate whether selenium nanoparticles (SeNPs) can stimulate bone formation and inhibit the bone loss involved in hyperglycemia-induced osteoporosis. Methods: Rat osteoblastic UMR-106 cells were used for in vitro studies and female Sprague–Dawley rats were used for type 2 diabetes-associated osteoporosis in vivo study. Results: In vitro studies show that SeNPs promote osteoblast differentiation via modulating alkaline phosphatase (ALP) activity, and promoting calcium nodule formation and collagen content. The authors also provide evidence regarding the involvement of the BMP-2/MAPKs/β-catenin pathway in preventing diabetic osteoporosis. Further, in vivo and ex vivo studies suggested that SeNPs can preserve mechanical and microstructural properties of bone. Conclusion: To the best of our knowledge, this study provides the first evidence regarding the therapeutic benefits of SeNPs in preventing diabetes-associated bone fragility.