Construction of double-layer bone-on-a-chip containing bone matrix / 中华创伤杂志

Objective:To construct a double-layer bone-on-a-chip containing bone matrix, with which the process of osteoblast and osteoclast differentiation in vitro is stimulated, aiming to provide a new platform for the development of osteoporosis medications. Methods:Software WorkSoild was used to design the double-layer and double-channel bone-on-a-chip and the template was fabricated by photolithography. With polydimethylsiloxane (PDMS) as the raw material, the main body of the chip was prepared by mold fabrication. The inlets and outlets of the four channels of the culture room were separated with bovine cortex bones and sealed with liquid storage columns. In the chip verification experiment, chips were divided into osteogenic and osteoclastic induction groups and osteogenic and osteoclastic control groups. In the osteogenic and osteoclastic induction groups, precursor cells of mouse embryonic osteoblast, MC3T3-E1 and mouse macrophage RAW264.7 were inoculated on the chip separately. Osteogenic induction lasted 14 days and osteoclastic induction 7 days. MC3T3-E1 cells and RAW264.7 cells were not induced in the osteogenic and osteoclastic control groups. The following indicators were observed: (1) Appearance and sealing performance of the chip: After the chip was prepared, photos were taken to observe its appearance and sealing tests were conducted to observe its sealing performance. (2) Biocompatibility: At 3 days after MC3T3-E1 cells were inoculated onto the chip and cultured and at 1, 3 and 5 days after RAW264.7 cells were inoculated onto the chip and cultured, the cell survival was observed with calcein acetoxymethyl ester/propidium iodide (AM/PI) staining and Cell Counting Kit 8 (CCK-8). (3) Osteogenic differentiation: Alkaline phosphatase (ALP) staining and alizarin red staining were performed on the cells in the osteogenic induction group to observe the osteogenic induction. RNA was collected from the osteogenic induction group and the osteogenic control group, the expression of osteoblast marker Runt-related transcription factor 2 (RUNX2), osteocalcin (OCN) and type I collagen (COL1A1) was detected by real-time florescent quantitative PCR (qPCR), and the differentiation degree and osteogenic ability of osteoblasts were observed. (4) Osteoclast differentiation: tartrate-resistant acid phosphatase (TRAP) staining was performed on cells in the osteoclastic induction group to observe osteoclast differentiation. RNA was extracted from the osteoclastic induction group and the osteoclastic control group for qPCR of osteoclast differentiation-related genes, and the expression levels of the osteoclast marker gene TRAP, cathepsin K (CTSK) and dendritic cell specific transmembrane protein (DC-STAMP) were detected.Results:The double-layer bone-on-a-chip containing bone matrix was 3 cm×3 cm in size and transparent as a whole. The structure of the system on the chip system was compact and had no seepage. It was shown by calcein AM/PI staining that at 3 days after MC3T3-E1 cells and RAW264.7 cells were cultured, very few red fluorescent dead cells were found. CCK-8 test showed that within 5 days after being cultured, the cell viability was all above 90%, indicating that the biocompatibility of the chip was good and the cells could survive and proliferate normally. The results of ALP and alizarin red staining showed that MC3T3-E1 cells successfully differentiated into osteoblasts and produced calcified nodules in the osteogenic induction group at 14 days after the induction. The qPCR results showed that the relative expression level of RUNX2 in MC3T3-E1 cells in the osteogenic induction group was 4.98±0.74, which was significantly higher than that of the control group (0.99±0.03) ( P<0.01). The relative expression level of OCN in MC3T3-E1 cells was 7.98±0.76, which was significantly higher than that of the control group (1.00±0.06) ( P<0.01). The relative expression level of COL1A1 in MC3T3-E1 cells was 7.07±0.56, which was significantly higher than that of the control group (0.97±0.03) ( P<0.01). The TRAP staining results showed that the RAW264.7 cells in the osteoclastic induction group differentiated to giant multinucleated osteoclasts, and TRAP protein was expressed in large quantity in the osteoclasts. The results of qPCR showed that the relative expression level of TRAP in RAW264.7 cells in the osteoclastic induction group was 3.35±0.37, which was significantly higher than that of the control group (1.01±0.06) ( P<0.01). The relative expression level of CTSK in RAW264.7 cells was 3.46±0.79, which was significantly higher than that of the control group (1.01±0.05) ( P<0.01). The relative expression level of DC-STAMP in RAW264.7 cells was 1.92±0.12, which was significantly higher than that of the control group (0.98±0.08) ( P<0.01). Conclusions:The double-layer bone-on-a-chip containing bone matrix is compact in structure, can be cultured in vitro for a long time, has good biocompatibility and can be used for inducing osteogenic and osteoclast differentiation. Therefore, it is expected to provide a new research platform for exploring the mechanism of osteoporosis and medication screening.

Corylin in Treatment of Metabolic Bone Diseases： A Review / 中国实验方剂学杂志

Bone is a dynamic tissue undergoing continuous regeneration and reconstruction， and its metabolic activities are mainly regulated by bone formation mediated by osteoblasts and bone resorption mediated by osteoclasts. In addition， a variety of cells such as adipocytes， inflammatory cells， endothelial cells， and nerve cells can affect bone metabolism by changing the bone marrow microenvironment. The incidence of bone metabolic diseases caused by bone metabolism disorders is increasing with aging of the population. At present， the clinical treatment of bone metabolic diseases has the disadvantages of long cycle， high cost and many side effects. Therefore， there is an urgent need for safe and effective prevention and treatment drugs. Corylin is an isoflavonoid extracted from Psoraleae Fructus， which has a variety of pharmacological effects such as anti-inflammatory， anti-oxidation， anti-tumor， anti-atherosclerosis， attenuating obesity and improving insulin resistance. Studies have shown that corylin not only exerts osteoprotective effects by promoting osteoblast differentiation and inhibiting osteoclast differentiation， but also plays a positive role in bone metabolism by regulating lipid metabolism， inflammatory response， angiogenesis and anti-aging. The current review overviews the effects and mechanisms of corylin on regulating bone metabolism directly or indirectly， hoping to open up a new perspective for the prevention and treatment of osteoporosis， fracture， osteoarthritis and other related diseases.

Modulation of osteoclastogenesis by macrogeometrically designed hydrophilic dual acid-etched titanium surfaces

Abstract The aim of this study was to evaluate the influence of implant macrodesign and surface hydrophilicity on osteoclast (OC) differentiation, activation, and survival in vitro. Titanium disks were produced with a sandblasted, dual acid-etched surface, with or without additional chemical modification for increasing hydrophilicity (SAE-HD and SAE, respectively) and different macrodesign comprising trapezoidal (HLX) or triangular threads (TMX). This study evaluated 7 groups in total, 4 of which were experimental: HLX/SAE-HD, HLX-SAE, TMX/SAE-HD, and TMX/SAE; and 3 control groups comprising OC differentiated on polystyrene plates (CCPC): a positive CCPC (+), a negative CCPC (-), and a lipopolysaccharide-stimulated assay positive control group, CCPC-LPS. Murine macrophage RAW264.7 cells were seeded on the disks, differentiated to OC (RAW-OC) by receptor activator of nuclear factor-κB ligand (RANKL) treatment and cultured for 5 days. Osteoclast differentiation and cell viability were respectively assessed by specific enzymatic Tartrate-Resistant Acid Phosphatase (TRAP) activity and MTT assays. Expression levels of various OC-related genes were measured at the mRNA level by quantitative polymerase chain reaction (qPCR). HLX/SAE-HD, TMX/SAE-HD, and HLX/SAE significantly suppressed OC differentiation when compared to CCPC (+). Cell viability was significantly increased in TMX/SAE and reduced in HLX/SAE-HD. In addition, the expression of Interleukin (IL)-6 and Tumour Necrosis Factor (TNF)-α was upregulated in TMX/SAE-HD compared to CCPC (+). Hydrophilic surfaces negatively modulate macrophage/osteoclast viability. Specifically, SAE-HD with double triangular threads increases the cellular pro-inflammatory status, while surface hydrophilicity and macrodesign do not seem to have a distinct impact on osteoclast differentiation, activation, or survival.

An in vitro study of the effect of Mycobacterium tuberculosis infection on the expression of bone destruction-related factors in osteoclasts / 中国脊柱脊髓杂志

Objectives:To establish a model of Mycobacterium tuberculosis infection of osteoclasts(OC)and explore the mechanism of Mycobacterium tuberculosis infection on OC.Methods:Peripheral blood mononuclear cells(peripheral blood mononuclear cells,PBMCs)were isolated from healthy volunteers.Receptor activator of nuclear factor-KB ligand(RANKL)and macrophage-colony stimulating factor(M-CSF)were used to make PBMCS into OC,and tartrate resistant acid phosphatase(TRAP)staining was performed on the cells.The constructed kanamycin resistant H37Rv pMV261-GFP green fluorescent strain was resuscitated and cultured with 10％oleic albumin dextrose catalase(OADC),7H9 and kanamycin containing Mycobacterium tuberculosis special liquid medium in an incubator at 37℃ until the optical density(OD)value was about 0.5 at 600nm.The OC cells cultured alone were set as the blank control group.And OC cells were also infected with Mycobacterium tuberculosis at different multiplicity of infection(MOI)for 24h,and MTT colorimetric method was used to detect cell survival rate.The MOI with the highest cell survival rate was selected as experimental MOI,and OC cells infected with H37Rv at experimental MOI were set as the experimental group.Fluorescence microscopy and Mycobacterium tuberculosis acid-fast staining were used to observe the transfection of Mycobacterium tuberculosis at the experimental MOI.Quantitative real-time PCR(qRT-PCR)was used to detect the expressions of non-receptor tyrosine kinase C-src,cathepsin K(CK),carbonic anhydrase 2(CA2),Integrin-β3 and matrix metalloproteinase-9(MMP-9).Immunohistochemistry was used to detect the expressions of P-src,CK,CA2,Integrin-β3 and MMP-9 on the cell surface.Western blot(WB)was used to detect the protein expression levels of P-src,CK,CA2,Integrin-β3,and MMP-9.Results:TRAP staining showed that more than 90％of the cells were OC after 15d of culture,which could be used for experiments.The results of MTT colorimetric assay showed that the cell survival rate was the highest when the MOI was 20:1(P＜0.05).This transfection multiplicity can be used as the concentration of experimental group.Fluorescence microscopy showed that when the transfection multiplicity ratio was 20:1,the green fluorescent Mycobacterium tuberculosis entered the OC and was successfully transfected into the OC.The results of acid-fast staining after infection of OC with Mycobacterium tuberculosis showed that when the MOI was 20:1,the acid-fast Mycobacterium tuberculosis stained red entered OC and was also successfully transfected into OC.The results of qRT-PCR,cell immunohistochemistry,and WB showed that the expressions of MMP-9,CK,C-src,CA2,and Integrin-β3 in the experimental group were higher than those in the blank control group(P＜0.05).Conclusions:Mycobacterium tuberculosis can transfect OC;Compared with the blank control group,the levels of five bone destruction factors in the experimental group transfected with OC by Mycobacterium tuberculosis were increased,suggesting that bone destruction of spinal tuberculosis may be related to this,which may provide a new exploration direction for the diagnosis and treatment of bone tuberculosis diseases.

Effect of endocannabinoid system on senile osteoporosis / 中华骨科杂志

Osteoporosis is a common disease of old age that affects millions of people worldwide. Besides, it has been a chronic disease difficult to treat in the elderly, so it is of great significance to develop new drugs for the treatment of senile osteoporosis. The endocannabinoid system contains cannabinoid ligands, endocannabinoid receptors, and enzymes required for the synthesis and degradation of endocannabinoids, which play an important role in bone metabolism. Preclinical studies using endocannabinoid system-based therapies in animal models and in vitro have shown that endocannabinoid systems can prevent senile osteoporosis and highlight their therapeutic potential for senile osteoporosis. In this paper, PubMed, ScienceDirect, CNKY, and Wanfang databases were searched for articles related to the endocannabinoid system and osteoporosis. This paper analyzed the pathogenesis of senile osteoporosis (such as calcium, active vitamin D3 deficiency or insufficiency, sex hormone deficiency, cell function decline and secondary to chronic diseases, etc.), and reviewed the various components of the endocannabinoid system and their application in osteoporosis by regulating bone homeostasis in recent years, providing a new direction for the clinical treatment of senile osteoporosis.

Effects of Zuogui Pill on osteoclast activity and expression of miR-133b-3p/RhoA in postmenopausal osteoporosis rats / 国际中医中药杂志

Objective:To study the effects of Zuogui Pills on the expressions of miR-133b-3p and RhoA in osteoclasts of postmenopausal osteoporosis rats; To discuss its potential mechanism.Methods:SD female rats were randomly divided into normal group, model group, sham-operation group, and Zuogui Pills group using a random number table method, with 6 rats in each group. The model group and Zuogui Pills group were treated with oophorectomy to construct a rat model of osteoporosis. Zuogui Pills group was orally administered with Zuogui Pills decoction at a concentration of 10 g/kg for 12 consecutive weeks. Colorimetric method was used to measure the serum calcium and phosphorus levels of rats, and ELISA method was used to detect ALP levels. Bone density meter was used to measure the bone density of the femurs of rats in each group. The osteoclast of each group were cultured, and the expressions of RANKL and RUNX2 protein were detected by Western blot. MiRNA sequencing and differential expression analysis were performed on bone tissues of rats. Osteoclasts were treated with miR-133b-3p mimic and its negative control. The cell proliferation activity of osteoclasts was detected by cell counting kit-8 (CCK-8). The osteoclast differentiation activity was detected by the tartrate-resistant acid phosphatase staining. The dual-luciferase reporter assay was used to detect the relationship between miR-133b-3p and RhoA. The "rescue" experiment of miR-133b-3p mimic and RhoA co-expression were used to study the molecular regulatory mechanism of Zuogui Pills on osteoclast activity.Results:Compared with the model group, the bone mineral density of Zuogui Pills group significantly increased ( P<0.05, P<0.01), the levels of calcium and phosphorus in serum increased, the level of alkaline phosphatase ALP decreased ( P<0.05), the expression of RANKL protein decreased, and the expression of RUNX2 protein increased. Sequencing results showed that rno-miR-133b-3p was down-regulated in osteoclasts of postmenopausa osteoporosis rats treated with Zuogui Pills with the maximum difference ( P<0.01). Q-PCR results showed that the expression of miR-133b-3p in osteoclasts of Zuogui Pills group was significantly lower than that of the model group. The upregulation of miR-133b-3p could significantly promote the cell proliferation and differentiation of osteoclasts. RhoA overexpression could reverse the excessive proliferation and differentiation of osteoclasts caused by miR-133b-3p overexpression. Conclusions:RhoA is the target gene regulated by miR-133b-3p. Zuogui Pills can inhibit the activity of osteoclasts by regulating miR-133b-3p/RhoA axis, relieving the symptoms of osteoporosis.

Research progress on an autophagy-mediating AMPK pathway involving bone metabolism-related cells that regulate bone homeostasis in periodontitis / 口腔疾病防治

@#Osteoclasts are the only cells responsible for bone resorption in the body, and osteoblasts are the main cells responsible for bone regeneration in the body. Under physiological conditions, these cells maintain a dynamic balance to maintain bone homeostasis. It was widely believed that the imbalance of bone metabolism is mainly affected by the expression of related inflammatory factors. However, with the gradual expansion of related studies in recent years, autophagy has been shown to be closely related to the differentiation, apoptosis and functions of osteoclasts and osteoblasts. AMP-activated protein kinase (AMPK) is an important regulator of energy metabolism in vivo and is involved in the regulation of autophagy and bone homeostasis in bone metabolism-related cells. Periodontitis is a chronic infectious disease, and its typical symptoms are alveolar bone resorption. At present, controlling the level of periodontal inflammation and alveolar bone resorption more effectively in clinical practice remains a challenge. The detection of AMPK and autophagy levels in bone metabolism-related cells shows certain prospects for the clinical prevention and treatment of periodontitis in the future. Therefore, this article reviews the regulation of periodontal inflammation levels and bone homeostasis through cell autophagy related to AMPK-mediated bone metabolism.

Regulatory function and mechanism of autophagy on osteoclast / 中国骨伤

Osteoclast (OC) is multinucleated, bone-resorbing cells originated from monocyte/macrophage lineage of cells, excessive production and abnormal activation of which could lead to many bone metabolic diseases, such as osteoporosis, osteoarthritis, etc. Autophagy, as a highly conserved catabolic process in eukaryotic cells, which plays an important role in maintaining cell homeostasis, stress damage repair, proliferation and differentiation. Recent studies have found that autophagy was also involved in the regulation of osteoclast generation and bone resorption. On the one hand, autophagy could be induced and activated by various factors in osteocalsts, such as nutrient deficiency, hypoxia, receptor activator of nuclear factor(NF)-κB ligand(RANKL), inflammatory factors, wear particles, microgravity environment, etc, different inducible factors, such as RANKL, inflammatory factors, wear particles, could interact with each other and work together. On the other hand, activated autophagy is involved in regulating various stages of osteoclast differentiation and maturation, autophagy could promote proliferation of osteoclasts, inhibiting apoptosis, and promoting differentiation, migration and bone resorption of osteoclast. The classical autophagy signaling pathway mediated by mammalian target of rapamycin complex 1(mTORC1) is currently a focus of research, and it could be regulated by upstream signalings such as phosphatidylinositol 3 kinase(PI-3K)/protein kinase B (PKB), AMP-activated protein kinase(AMPK). However, the paper found that mTORC1-mediated autophagy may play a bidirectional role in regulating differentiation and function of osteoclasts, and its underlying mechanism needs to be further ciarified. Integrin αvβ3 and Rab protein families are important targets for autophagy to play a role in osteoclast migration and bone resorption, respectively. In view of important role of osteoclast in the occurrence of various bone diseases, it is of great significance to elucidate the role of autophagy on osteoclast and its mechanism for the treatment of various bone diseases. The autophagy pathway could be used as a new therapeutic target for the treatment of clinical bone diseases such as osteoporosis.

Experimental study of subcutaneous adipose-derived stem cells inhibiting orthodontic root resorption / 中国修复重建外科杂志

OBJECTIVE@#To investigate the effect of human subcutaneous adipose-derived stem cells (hADSCs) local transplantation on orthodontically induced root resorption (OIRR) and provide theoretical and experimental basis for the clinical application of hADSCs to inhibit OIRR.@*METHODS@#Forty 8-week-old male Sprague Dawley rats were randomly divided into experimental group and control group, with 20 rats in each group, to establish the first molar mesial orthodontic tooth movement (OTM) model of rat right maxillary. The rats in the experimental group were injected with 25 μL of cell suspension containing 2.5×10 5 hADSCs on the 1st, 4th, 8th, and 12th day of modeling, while the rats in the control group were injected with 25 μL of PBS. The rat maxillary models were obtained before and after 7 and 14 days of force application, and 10 rats in each group were killed and sampled after 7 and 14 days of force application. The OTM distance was measured by stereomicroscope, the root morphology of the pressure side was observed by scanning electron microscope and the root resorption area ratio was measured. The root resorption and periodontal tissue remodeling of the pressure side were observed by HE staining and the root resorption index was calculated. The number of cementoclast and osteoclast in the periodontal tissue on the pressure side was counted by tartrate resistant acid phosphatase staining.@*RESULTS@#The TOM distance of both groups increased with the extension of the force application time, and there was no significant difference ( P<0.05). There was no significant difference in OTM distance between the experimental group and the control group after 7 and 14 days of force application ( P>0.05). Scanning electron microscope observation showed that small and shallow scattered resorption lacunae were observed on the root surface of the experimental group and the control group after 7 days of force application, and there was no significant difference in the root resorption area ratio between the two groups ( P>0.05); after 14 days of application, the root resorption lacunae deepened and became larger in both groups, and the root resorption area ratio in the experimental group was significantly lower than that in the control group ( P<0.05). The range and depth of root absorption in the experimental group were smaller and shallower than those in the control group, and the root absorption index in the experimental group was significantly lower than that in the control group after 14 days of force application ( P<0.05). The number of cementoclast in the experimental group was significantly lower than that in the control group after 7 and 14 days of force application ( P<0.05); the number of osteoclasts in the experimental group was significantly lower than that in the control group after 14 days of force application ( P<0.05).@*CONCLUSION@#Local transplantation of hADSCs may reduce the area and depth of root resorption by reducing the number of cementoclasts and osteoclasts during OTM in rats, thereby inhibiting orthodontic-derived root resorption.

Investigação de marcadores moleculares sanguíneos durante a infecção pelo vírus Chikungunya / Investigation of blood molecular markers during Chikungunya virus infection

A febre Chikungunya (CHIKF) é uma infecção viral causada pelo vírus Chikungunya (CHIKV). Os sintomas agudos incluem febre alta de início súbito, erupção cutânea, poliartrite e poliartralgia. Embora a infecção geralmente seja resolvida em menos de duas semanas, muitos pacientes experenciam recorrente dor e inflamação nas articulações, que podem persistir por anos. Esse estudo buscou marcadores moleculares no sangue de infectados pelo CHIKV que estejam associados a dor articular e cronicidade da CHIKF. O sequenciamento de receptores de células B (BCR) e T (TCR) demonstrou que a infecção por CHIKV diminui a diversidade desses receptores. Essa diversidade é ainda menor, durante a fase aguda da infecção, naqueles pacientes que irão desenvolver cronicidade. A menor diversidade de BCR em infectados está associada a um aumento na expressão de genes envolvidos na diferenciação e ativação de osteoclastos pela sinalização RANK/RANKL. Em adição, a cronicidade pode estar relacionada um aumento na expressão do gene ZBTB7A cuja expressão confere maior resistência a apoptose em precursores de osteoclastos naqueles pacientes que vão se tornar crônicos. Caso o envolvimento dos osteoclastos durante a patogênese de CHIKF seja confirmado, os pacientes poderão se beneficiar de abordagens terapêuticas já existentes como alternativas adicionais ao tratamento de CHIKF

Chikungunya fever (CHIKF) is a viral infection caused by the Chikungunya virus (CHIKV). Acute symptoms include sudden-onset high fever, rash, polyarthritis, and polyarthralgia. Although the infection usually resolves within two weeks, many patients experience recurrent joint pain and inflammation, which can persist for years. This study sought molecular markers in the blood of CHIKV-infected individuals that are associated with joint pain and chronicity of CHIKF. Sequencing of B (BCR) and T (TCR) cell receptors demonstrated that CHIKV infection decreases the diversity of these receptors. The diversity is even lower, during the acute phase of the infection, in those patients who will develop chronicity. The lower diversity of BCR in infected individuals is associated with an increase in the expression of genes involved in the differentiation and activation of osteoclasts by RANK/RANKL signaling. In addition, chronicity may be related to an increase in the expression of the ZBTB7A gene whose expression confers greater resistance to apoptosis in osteoclast precursors in those patients who will become chronic. If osteoclast role during CHIKF pathogenesis is confirmed, patients may benefit from existing therapeutic approaches as additional alternatives to CHIKF treatment

Channa Striata and Hyperbaric Oxygen Therapy Combination for Pressure Areas in Orthodontic Treatment

ABSTRACT Objective: To study the effect of using a combination of Channa Striata gel and hyperbaric oxygen therapy on pressure areas during orthodontic treatment. Material and Methods: The study was conducted using the ARRIVE Essential 10 guidelines. In this study, 35 3-4 months male guinea pigs (Cavia Cobaya) weighing 300-400 grams were used and divided into 5 groups (n=7). Decalcification was performed to dissolve the dental calcium and jawbone to cut the tissue properly. The decalcification was performed for 30 days. Then preparations were made with HE (Hematoxylin Eosin), observed using a microscope, and counted the number of osteoclasts and macrophages on a light microscope with 400 times magnification. The results of the preparations were analyzed using the SPSS program. Results: The Kruskal-Wallis test of macrophage cells and the ANOVA test of osteoclast cells showed significant results between all groups (p<0.05). Conclusion: The effect of hyperbaric oxygen therapy 2,4 ATA administered on days 8-14 and Channa Striata extract gel administered on days 3-14 can increase the number of macrophages in the periodontal ligament and osteoclasts in the alveolar bone in the pressure area during orthodontic tooth movement.

Multi-functional osteoclasts in matrix-based tissue engineering bone / 中华创伤杂志(英文版)

The repair of bone defects, especially for the large segment of bone defects, has always been an urgent problem in orthopedic clinic and attracted researchers' attention. Nowadays, the application of tissue engineering bone in the repair of bone defects has become the research hotspot. With the rapid development of tissue engineering, the novel and functional scaffold materials for bone repair have emerged. In this review, we have summarized the multi-functional roles of osteoclasts in bone remodeling. The development of matrix-based tissue engineering bone has laid a theoretical foundation for further investigation about the novel bone regeneration materials which could perform high bioactivity. From the point of view on preserving pre-osteoclasts and targeting mature osteoclasts, this review introduced the novel matrix-based tissue engineering bone based on osteoclasts in the field of bone tissue engineering, which provides a potential direction for the development of novel scaffold materials for the treatment of bone defects.

Effects of polydopamine-coated porous titanium alloy scaffolds loaded with zoledronic acid-gelatin nanoparticles for topical sustained drug release on osteoclasts: an in vitro study / 中华创伤骨科杂志

Objective:To analyze the effects of a novel type of polydopamine (PDA)-coated porous titanium alloy scaffolds loaded with zoledronic acid-gelatin nanoparticles (ZOL-GNPs) for topical sustained drug release on osteoclasts in vitro. Methods:After porous titanium alloy scaffolds were fabricated using electron beam melting technique and ZOL-GNPs with different ZOL concentrations (0, 1, 10, 50, 100, 500 μmol/L) were prepared by desolvation method, PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs were constructed by combining the two. The characteristics of the scaffolds were analyzed. The biomechanics of 3 different scaffolds (bare porous titanium alloy scaffolds, PDA-coated porous titanium alloy scaffolds, and PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs) were investigated. Drug release detection was carried out by high performance liquid chromatography on the 1st, 4th, 7th, 14th, 21st, and 28th days respectively. The osteoclasts were inoculated into the novel scaffolds with different ZOL concentrations. The expression of osteoclast-related genes was detected by real-time quantitative (RT)-polymerase chain reaction (PCR); the expression of osteoclast-related proteins was detected by Western-blot.Results:The PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs were successfully constructed. Electron microscope scanning showed that the GNPs were well spheroidized, smooth in surface, and uniformly dispersed, with a particle size of (243.6±63.4) nm. The ZOL-GNPs were uniformly compounded on the surface and in the pores of the scaffolds, and the spheres were regular in shape with no adhesion. The biomechanical experiments showed that the elastic moduli of the porous titanium alloy scaffolds under 3 different conditions were (1.81±0.12) GPa, (1.80±0.23) GPa and (1.81±0.15) GPa, showing no significant difference ( P> 0.05). The drug release percentage in the porous titanium alloy scaffolds was obviously high on the first day, and increased gradually and slowly in the subsequent 27 days. In the scaffolds with a low concentration ZOL, more osteoclasts adhered and proliferated; in the 50 μmol/L scaffolds, spheroid cells appeared; the spheroid cells increased and even apoptosis occurred with an increase in the ZOL concentration. RT-PCR showed that the expression of Ctsk gene and TRAP gene increased with the increased ZOL concentration, peaked in the 50 μmol/L scaffolds, and then decreased with the increased concentration, showing statistically significant differences ( P < 0.05). Western-blot showed that the expression pattern of Ctsk and TRAP was similar to that of their related genes. Conclusions:The novel PDA-coated porous titanium alloy scaffolds loaded with ZOL-GNPs demonstrate good mechanical properties and an anti-osteoporosis effect via their topical sustained drug release. The scaffolds with a ZOL concentration of 50 μmol/L may exert the best effect on inhibition of osteoclasts.

Correlation between proteoglycan and alveolar bone resorption in a mouse periodontitis model / 口腔疾病防治

Objective@#To analyze changes in proteoglycan and its correlation with alveolar bone resorption in periodontitis. @*Methods @#Twelve eight-week-old C57BL/6J male mice were selected, and the periodontitis model was established by ligating the right maxillary second molar with 6-0 silk thread. The nonligated part of the left maxilla was used as the control. The mice were killed 14 days after the operation. Micro-CT was used to assess alveolar bone resorption. HE staining was used to observe the alveolar bone profile, and TRAP staining was conducted to examine the positive rate of osteoclasts. The expression of proteoglycan-related genes, such as aggrecan (ACAN), biglycan (BGN), versican (VCAN), decorin (DCN), osteoclast-related genes, such as cathepsin K (CTSK), matrix metalloprotein-9 (MMP-9), and receptor activator of nuclear factor kappa-B ligand (RANKL), and inflammation-related genes, such as interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α), was detected by real-time quantitative PCR. Additionally, the correlation of the expression of proteoglycans with osteoclast-related genes and inflammation-related genes was evaluated by Pearson correlation analysis.@* Results@#The resorption of alveolar bone on the periodontitis side increased. TRAP staining showed that the number of osteoclasts was substantially increased in the maxilla with periodontitis. Real-time quantitative PCR demonstrated that compared with the control side, the expression of proteoglycan-related genes, such as ACAN, BGN, and DCN, was decreased, whereas the expression of the VCAN gene was significantly increased in the periodontitis side. Meanwhile, the expression of osteoclast-related genes, such as CTSK, MMP-9, and RANKL, and inflammation-related genes, such as IL-1β, IL-6, and TNF-α, was markedly increased in the periodontitis side (P<0.05). Pearson correlation analysis indicated a negative correlation between the expression of proteoglycans and the mRNA levels of osteoclast-related genes and inflammation-related genes (P<0.05). @*Conclusion @#The expression of proteoglycan was closely related to alveolar bone resorption in a periodontitis model.

Research progress on interaction between osteoblasts and osteoclasts / 中国药理学通报

Osteoclasts and osteoblasts play an important role in bone remodeling, and their dysfunction can lead to a series of bone diseases, such as osteoporosis and osteoselerosis.Reeent studies have found that the active substances secreted by osteo¬blasts can regulate the recruitment, attachment, proliferation and differentiation of osteoclasts, thus affecting bone resorption.'Hie active substances derived from osteoclasts can also regulate the formation, survival, differentiation and mineralization of os¬ teoblasts and affect bone fonnation.In this paper, the active substances produced by osteoblasts and osteoclasts at present are summarized, and their functions are analyzed, so as to provide new ideas for dnjgs regulation of the dynamic balance between osteoblasts and osteoclasts.

Bioactive glass-ceramic for bone tissue engineering: an in vitro and in vivo study focusing on osteoclasts

Abstract: Despite the crucial role of osteoclasts in the physiological process of bone repair, most bone tissue engineering strategies have focused on osteoblast-biomaterial interactions. Although Biosilicate® with two crystalline phases (BioS-2P) exhibits osteogenic properties and significant bone formation, its effects on osteoclasts are unknown. This study aimed to investigate the in vitro and in vivo effects of BioS-2P on osteoclast differentiation and activity. RAW 264.7 cells were cultured in osteoclastogenic medium (OCM) or OCM conditioned with BioS-2P (OCM-BioS-2P), and the cell morphology, viability, and osteoclast differentiation were evaluated. BioS-2P scaffolds were implanted into rat calvarial defects, and the bone tissue was evaluated using tartrate-resistant acid phosphatase (TRAP) staining and RT-polymerase chain reaction (PCR) after 2 and 4 weeks to determine the gene expressions of osteoclast markers and compare them with those of the bone grown in empty defects (Control). OCM-BioS-2P favored osteoclast viability and activity, as evidenced by an increase in the TRAP-positive cells and matrix resorption. The bone tissue grown on BioS-2P scaffolds exhibited higher expression of the osteoclast marker genes (Ctsk, Mmp 9, Rank) after 2 and 4 weeks and the RankL/Opg ratio after 2 weeks. Trap gene expression was lower at 2 weeks, and a higher number of TRAP-stained areas were observed in the newly formed bone on BioS-2P scaffolds at both 2 and 4 weeks compared to the Controls. These results enhanced our understanding of the role of bioactive glass-ceramics in bone repair, and highlighted their role in the modulation of osteoclastic activities and promotion of interactions between bone tissues and biomaterials.

Relationship between lactic acid concentration and osteoclast differentiation of mouse monocytes / 中国组织工程研究

BACKGROUND: Preliminary study found that polylactic acid composite material could accelerate the bone construction rate, and the underlying mechanism still needs to be studied further. OBJECTIVE: To investigate the effect of lactic acid at different concentrations on osteoclast differentiation of mononuclear cells in mice. METHODS: Mouse RAW264.7 cells were cultured in DMEM with 0 (control group), 5, 10 and 20 mmol/L lactic acid, respectively, under the induction of 50 µg/L RANKL for 5 days. The effect of lactic acid concentration on the cell proliferation rate was analyzed by cell counting kit-8 assay. Tartrate resistant acid phosphatase positive polykaryotic cells were stained and counted with tartrate resistant acid phosphatase staining kit. mRNA expression levels of acid phosphatase 5, nuclear factor of activated T-cells 1 and RANK were detected by RT-PCR. Protein expression levels of cathepsin K and nuclear factor of activated T-cells 1 were detected by western blot assay. RESULTS AND CONCLUSION: (1) 5 mmol/L lactic acid produced the highest proliferation rate of raw264.7 cells, whereas the 20 mmol/L lactic acid produced lowest cell proliferation rate. Compared with the control group, the proliferation rate of raw264.7 cells by 10 mmol/L lactic acid was insignificant. (2) Tartrate resistant acid phosphatase staining showed the highest positive rate and mRNA expression levels of acid phosphatase 5, nuclear factor of activated T-cells 1 and RANK under the condition of 10 mmol/L lactic acid. (3) With the increase of lactic acid concentration, the expression level of cathepsin K increased, while the expression level of nuclear factor of activated T-cells 1 was on a decline. (4) Under the current experimental conditions, with the increase of lactic acid concentration, the ability of lactic acid to promote the osteoclast differentiation of mouse RAW264.7 cells is firstly increased and then decreased, and 10 mmol/L lactic acid was the optimal concentration to promote the osteoclast differentiation of mouse RAW264.7 cells. Lactic acid can affect the osteoclastic differentiation of mouse raw264.7 cells by nuclear factor of activated T-cells 1 in nuclear factor-KB signaling pathway.

Humulus lupulus L. Extract Prevents Ovariectomy-Induced Osteoporosis in Mice and Regulates Activities of Osteoblasts and Osteoclasts / 中国结合医学杂志

OBJECTIVE@#To systematically evaluate the protective effects of Humulus lupulus L. extract (HLE) on osteoporosis mice.@*METHODS@#In vivo experiment, a total of 35 12-week-old female ICR mice were equally divided into 5 groups: the sham control group (sham); the ovariectomy with vehicle group (OVX); the OVX with estradiol valerate [EV, 0.2 mg/(kg•d)] the OVX with low- or high-dose HLE groups [HLE, 1 g/(kg•d) and 3 g/(kg•d)], 7 in each group. Treatment began 1 week after the ovariectomized surgery and lasted for 12 weeks. Bone mass and trabecular bone mircoarchitecture were evaluated by micro computed tomography, and bone turnover markers in serum were evaluated using enzyme-linked immunosorbent assay (ELISA) kits. In vitro experiment, osteoblasts and osteoclasts were treated with HLE at doses of 0, 4, 20 and 100 µg/mL. Biomarkers for bone formation in osteoblasts and bone resorption in osteoclasts were analyzed.@*RESULTS@#Compared with the OVX group, HLE exerted bone protective effects by the increase of estradiol (P<0.05), the improvement of cancellous bone structure, bone mineral density (P<0.01) and the reduction of serum alkaline phosphatase (ALP), tartrate resistant acid phosphatase (TRAP), bone gla-protein, c-terminal telopeptides of type I collagen (CTX-I) and deoxypyridinoline levels (P<0.01 for all). In vitro experiment, compared with the control group, HLE at 20 µg/mL promoted the cell proliferation (P<0.01), and increased the expression of bone morphogenetic protein-2 and osteopontin levels in osteoblasts (both P<0.05). HLE at 100 µg/mL increased the osteoblastic ALP activities, and HLE at all dose enhanced the extracellular matrix mineralization (both P<0.01). Furthermore, compared with the control group, HLE at 20 µg/mL and 100 µg/mL inhibited osteoclastic TRAP activity (P<0.01), and reduced the expression of matrix metalloproteinase-9 and cathepsin K (both P<0.05).@*CONCLUSION@#HLE may protect against bone loss, and have potentials in the treatment of osteoporosis.

Effect of mechano-growth factor on osteoclast activity and its mechanism / 中华创伤杂志

Objective:To investigate the effect of mechano-growth factor（MGF）on osteoclast activity and its mechanism.Methods:The RAW264.7 precursor osteoclast cell line was cultured with 25 ng/ml macrophage-colony stimulating factor（M-CSF）and 30 ng/ml receptor activator of NF-κB ligand（RANKL），and identified by tartrate resistant acid phosphatase（TRAP）staining after 7 days of culture. Western blot anslysis was used to determine the effect of 45 ng/ml MGF on the phosphoinositide-3-kinase/protein kinase B（PI3K/AKT）signaling pathway in separated osteoclasts，including levels of AKT，phosphorylation（p）-AKT，lactation mammalian target of rapamycin（mTOR），p-mTOR and TRAP at 0，4，8 and 12 hours. Real-time fluorescence quantitative PCR was used to expressions of TRAP in osteoclasts at 0，4，8 and 12 hours. The PI3K/Akt phosphorylation inhibitor LY294002（20 μmol/L）combined with MGF（45 ng/ml）was used to act on osteoclasts，and expression levels of Akt，p-Akt，mTOR，p-mTOR and TRAP were detected by Western blot at 0，4，8 and 12 hours.Results:After culturing RAW264.7 cells with M-CSF and RANKL for 7 days，a large number of osteoclasts with positive TRAP staining can be obtained. Western blot analysis showed expression levels of Akt and mTOR did not change significantly over time（ P>0.05），expression levels of p-Akt and p-mTOR increased continuously from（2.18±0.34）pg/ml and（0.83±0.10）pg/ml at 0 hour to（3.86±0.36）pg/ml and（1.56±0.19）pg/ml at 12 hours（ P<0.05），and expression level of TRAP decreased significantly over time，from（5.66±0.47）pg/ml at 0 hour to（3.76±0.38）pg/ml at 12 hours（ P<0.05）. Real-time fluorescence quantitative PCR analysis of expression of TRAP in osteoclasts showed that MGF inhibited the expression of TRAP in osteoclasts，which decreased from 1.02±0.06 at 0 hour to 0.53±0.11 at 12 hours（ P<0.05）. After acting LY294002 combined with MGF on osteoclasts，Western blot analysis showed expression levels of Akt and mTOR did not change significantly over time（ P>0.05），expression levels of p-AKT and p-mTOR decreased significantly from（3.28±0.18）pg/ml and（3.29±0.22）pg/ml at 0 hour to（2.06±0.34）pg/ml and（2.04±0.20）pg/ml at 12 hours（ P<0.05），and expression level of TRAP had no significant difference over time（ P>0.05）. Conclusions:MGF inhibits osteoclast activity by inhibiting the expression of TRAP in osteoclasts through PI3K/Akt signaling pathway. LY294002 inhibits the expression of PI3K/Akt signaling pathway in osteoclasts，further verifying the mechanism of MGF inhibiting osteoclast activity，and this finding puts forward new ideas for clinical prevention and treatment of osteoporosis.

The Role of Signal Transducer and Activator of Transcription 3 in Bone Homeostasis and Load-Driven Bone Remodeling / 医用生物力学

Bone homeostasis is a relative balance between bone formation and resorption. Signal transducer and activator of transcription 3 (STAT3), which is closely related to bone homeostasis, takes part in multiple intracellular and extracellular signal pathways. STAT3 participates in the process of osteoblast differentiation regulated by several factors. It can also maintain bone homeostasis by regulating the recruitment, differentiation and activation of osteoclasts. In addition, STAT3 is involved in the interaction between osteoblasts and osteoclasts. Patients with STAT3 mutations can have several inherited bone metabolism diseases. Furthermore, STAT3 plays a critical role in load-driven bone remodeling. Mechanical stimulation promotes osteoblast differentiation and bone formation through activating or enhancing STAT3 expression during bone remodeling process. This review summarizes the participation of STAT3 in maintaining bone homeostasis together with its possible mechanisms and discusses the connection between STAT3 and mechanical stimulation in bone remodeling, so as to provide a potential pharmacological target for the treatment of bone diseases.