Aluminum trichloride inhibits osteoblastic differentiation through inactivation of Wnt/β-catenin signaling pathway in rat osteoblasts

Unraveling the neuroprotective mechanisms of naltrexone against aluminum-induced neurotoxicity

Aluminum (Al) is a known neurotoxic trace element linked to Alzheimer's disease (AD). Naltrexone, an opioid antagonist, has shown promising effects in reducing neuroinflammation at lower doses than those prescribed for addiction. This study aimed to determine the neuroprotective effects of naltrexone on Al-induced neurotoxicity in an in vitro AD model. The SH-SY5Y cells were first cultivated in a standard growth medium. Subsequently, the cells were induced to differentiate by decreasing the concentration of fetal bovine serum and introducing retinoic acid (RA) into the culture media. Subsequently, the inclusion of brain-derived neurotrophic factor (BDNF) was implemented in conjunction with RA. The process of differentiation was concluded on the seventh day. Study groups (n = 3) were designed as the control group, naltrexone group, Al group, Al-Nal group, Alzheimer' model (AD) group, Alzheimer model + Al-exposed group (AD-Al), Alzheimer model + Nal applied group (AD-Nal) and Alzheimer model + Al-exposed + Nal applied group (AD-Al-Nal). Hyperphosphorylated Tau protein as the specific marker of AD was measured in all groups. Glycogen synthase kinase-3 (GSK-3)β, Protein phosphatase 2A (PP2A), Akt and Wnt signaling pathways were analyzed comparatively. In addition, oxidative stress parameters (total antioxidant capacity, lipid peroxidase, protein carbonyl and reactive oxygen species) were measured comparatively in the study groups. The results showed that naltrexone reduced hyperphosphorylated tau protein levels by regulating GSK-3β, PP2A, Akt and Wnt signaling. Also, exposure to naltrexone decreased oxidative stress parameters. Based on these results, naltrexone shows promise as a potential therapy for AD, subject to additional clinical assessments.

Hydraulic calcium silicate-based root canal sealers mitigate proinflammatory cytokine synthesis and promote osteogenesis in vitro

Background/purpose

The mineralized tissue-inductive ability and anti-inflammatory properties of hydraulic calcium silicate-based (HCSB) sealers have not been fully elucidated. This study aimed to evaluate the effects of the HCSB sealers Bio-C sealer (BioC), Well-Root ST (WST), and EndoSequence BC sealer (BC), on osteoblastic differentiation/mineralization and proinflammatory cytokine synthesis by macrophages.

Materials and methods

Diluted extracts of set sealers or calcium chloride solutions of approximately equivalent Ca2+ concentrations were applied to a mouse osteoblastic cell line (Kusa-A1 cells) and lipopolysaccharide-stimulated mouse macrophage cell line (RAW264.7 cells). Expressions of osteoblastic markers in Kusa-A1 cells and proinflammatory cytokines in RAW264.7 cells were evaluated by reverse transcription-quantitative polymerase chain reaction and enzyme-linked immunosorbent assays. Mineralized nodules were detected by Alizarin red S staining. Cell proliferation was assessed by WST-8 assay and cell attachment on set sealers was examined by scanning electron microscopy.

Results

The three sealer extracts significantly upregulated osteocalcin and osteopontin mRNA, and promoted significant mineralized nodule formation in Kusa-A1 cells. The three sealer extracts significantly downregulated the mRNA expressions of interleukin (IL)-1α, IL-1β, IL-6, and tumor necrosis factor (TNF)-α and protein levels of IL-6 and TNF-α in RAW264.7 cells. Calcium chloride solutions induced osteoblastic differentiation/mineralization. AH Plus Jet (a control sealer) extract did not. The three HCSB sealers did not interfere with the growth and attachment of Kusa-A1 cells.

Conclusion

BioC, WST, and BC were biocompatible, upregulated osteoblastic differentiation/mineralization, and downregulated proinflammatory cytokine expression. Ca2+ released from HCSB sealers might be involved, at least in part, in the induction of osteoblastic differentiation/mineralization.

T-2 toxin-induced femur lesion is accompanied by autophagy and apoptosis associated with Wnt/β-catenin signaling in mice

T-2 toxin is one of the most common mycotoxins found in grain foods, animal feed, and other agricultural by-products causing food contamination and health threat. The skeletal system is the main target tissue for T-2 toxin. T-2 toxin exposure is also recognized as a potential contributor to multiple types of bone diseases, including Kashin-Beck disease. However, the mechanisms of T-2 toxin-induced bone toxicity remain unclear. In this study, 60 male C57BL/6 mice were exposed T-2 toxin with 0, 0.5, 1 or 2 mg/kg body weight by intragastric administration for 28 days, respectively. Femora were collected for the detections of femur lesion, bone formation factors, oxidative stress, autophagy, apoptosis, and Wnt/β-catenin signaling. Our research showed that T-2 toxin caused bone formation disorders, presenting as the reduction of the BMD and femur length, bone structure changes and abnormal bone formation proteins expressions, along with enhanced oxidative stress. Meanwhile, T-2 toxin increased expressions of autophagy-related proteins (Beclin 1, ATG5, p62, and LC3), and promoted apoptosis in mouse femur. Moreover, T-2 toxin suppressed the Wnt/β-catenin signaling and expressions of downstream target genes. Taken together, our data indicated T-2 toxin-induced femur lesion was accompanied by autophagy and apoptosis, which was associated with Wnt/β-catenin signaling.

Mechanisms of Hierarchical Topographies Tuning Bacteria and Cell Biological Responses to the Surfaces of Pure Titanium and Cu-Bearing Titanium Alloy

The competition between cells integration and bacterial colonization determines the fate of implantations. To reveal the effects of clinical implant topographies on osteoblast differentiation and bacterial biofilm formation, a series of micron/submicron/nano-hierarchical structures were created at pure titanium surfaces (Ti-I, Ti-II, Ti-III). It was found that the hierarchical structures promoted MC3T3-E1 cell differentiation through contact guidance and Ti-II processed the best osteogenic ability. Undesirably, hierarchical surfaces further accelerated the biofilm formation due to submicron structures with low interaction. To reduce the risk of bacterial infections, hierarchical structures were prepared on the antibacterial Cu-bearing titanium alloy surfaces (TiCu-I, TiCu-II, TiCu-III). Hierarchical topographies not only endowed TiCu surfaces with antibacterial trapping characteristics due to CuO doped in the outermost oxides layer but also shifted the corrosion behavior of TiCu alloy into activation-passivation, increasing the Cu-ion release rate and further promoting the osteogenic differentiation. TiCu-III possessed excellent antibacterial trapping ability and optimal osteogenic action. Finally, in the osteomyelitis-modeled mice, hierarchical topographies aggravated the bacterial infection around Ti implants, which entirely lost the osseointegration, while all of the TiCu surfaces significantly inhibited the infection and accelerated the formation of new bone tunnels around the implants. In vivo studies successfully confirmed the tuning mechanism of hierarchical topographies on the biological responses of bacteria and cells to the Ti and TiCu alloys, which would pave the way to develop novel biofunctionalized metal implants.

Aluminum chloride induces G0/G1 phase arrest via regulating the reactive oxygen species-depended non-canonical STAT1 pathway in hFOB1.19 cells

Treatment with aluminum chloride (AlCl₃) suppresses the growth of osteoblastic cells; however, the molecular mechanisms underlying the impact of AlCl₃ on cell growth have not been fully characterized. In this study, we observed that exposure of hFOB1.19 cells to AlCl₃ arrested cells at G₀/G₁ phase by inducing p21 expression. Further studies indicated that AlCl₃ upregulated the phosphorylation level of signal transducer and activator of transcription 1 (STAT1) at serine 727 site (Ser727). By chromatin immunoprecipitation and electrophoretic mobility shift assay, we found that AlCl₃ promoted STAT1/DNA binding activity to p21 promoter, thus resulting in the upregulation of p21. Moreover, siRNA-mediated knockdown of STAT1 attenuated p21 level induced by AlCl₃. Notably, using hFOB1.19 cells stably expressing dominant-negative STAT1 (Ser727Ala), we demonstrated that phosphorylation of STAT1 at Ser727 site is required for p21-mediated cycle arrest induced by AlCl₃. Mechanism investigation indicated that AlCl₃ stimulated the phosphorylation of JNK, and administration of JNK inhibitor SP600125 prevented AlCl₃-induced G₀/G₁ arrest through suppressing the phosphorylation of STAT1. Notably, pretreatment with N-acetyl-cysteine, a reactive oxygen species scavenger, conferred a significantly inhibitory effect on AlCl₃-mediated activation of JNK/STAT1 signaling pathway. Taken together, our findings provide the molecular mechanism for G₀/G₁ arrest induced by AlCl₃ in osteoblastic cells.

Protective effect of mitophagy against aluminum-induced MC3T3-E1 cells dysfunction

Aluminum (Al) is a ubiquitous environmental metal toxicant that causes osteoblast (OB) damage which leads to Al-related bone diseases. Mitochondrial damage plays a key role in Al-related bone diseases, and while mitophagy can clear damaged mitochondria and improve OB function, the relationship between mitophagy and Al-induced OB dysfunction is unknown. To explore the role of mitophagy in Al-induced OB dysfunction in vitro, we used 2 μM carbonyl cyanide m-chlorophenylhydrazone (CCCP) and 0.4 μM Cyclosporin A (CsA) to activate and inhibit mitophagy, respectively. MC3T3-E1 cells were treated with 0 mM AlCl₃ (control group); 2 mM AlCl₃ (Al group); 2 μM CCCP (CCCP group); 2 μM CCCP and 2 mM AlCl₃ (CCCP + Al group); 0.4 μM CsA (CsA group); 0.4 μM CsA and 2 mM AlCl₃ (CsA + Al group). The results showed that Al induced ultrastructural and functional impairment of MC3T3-E1 cells. Compared to the Al group, mitophagy activation caused mitochondrial membrane potentials to collapse, up-regulated PINK1, Parkin, and LC3 expression, down-regulated p62 expression, and increased mitophagosome numbers. Mitophagy activation also reduced Al-induced oxidative stress and MC3T3-E1 cell functional damage, as seen in improvement in cell viability, cellular calcium and phosphorus contents, and collagen I, osteocalcin, and bone alkaline phosphatase gene expression. Mitophagy inhibition had the opposite effects on activation. Overall, these results show that mitophagy can protect against Al-induced OB dysfunction.

Mitophagy and apoptosis mediated by ROS participate in AlCl3-induced MC3T3-E1 cell dysfunction

Aluminum (Al), as a common environmental pollutant, causes osteoblast (OB) dysfunction and then leads to Al-related bone diseases (ARBD). One of the mechanisms of ARBD is oxidative stress, which leads to an increase in the production of reactive oxygen species (ROS). ROS can induce mitochondrial damage, thereby inducing mitophagy and apoptosis. But whether mitophagy and apoptosis mediated by ROS, and the role of ROS in AlCl₃-induced MC3T3-E1 cell dysfunction is still unclear. In this study, MC3T3-E1 cells used 0 mM Al (control group), 2 mM Al (Al group), 5 mM N-acetyl cysteine (NAC) (NAC group), 2 mM Al and 5 mM NAC (Al + NAC group) for 24 h. We found AlCl₃-induced MC3T3-E1 cell dysfunction accompanied by oxidative stress, apoptosis, and mitophagy. While NAC, a ROS scavenger treatment, restored cell function and alleviated the mitophagy and apoptosis. These results suggested that mitophagy and apoptosis mediated by ROS participate in AlCl₃-induced MC3T3-E1 cell dysfunction.

Pulp tissue reaction to a self-adhesive, resin-based direct pulp capping material containing surface pre-reacted glass-ionomer filler

OBJECTIVE

This study aimed to evaluate the effect of direct pulp capping using an experimental self-adhesive resin for direct pulp capping (SRD) containing silica and surface pre-reacted glass-ionomer (S-PRG) filler on pulpal healing and to monitor the dentin bridge formation in rat pulp 2-4 weeks after operation.

METHODS

Five types of SRDs (SRD-0: S-PRG fillers 0 wt%; SRD-1: S-PRG fillers 9.1 wt%; SRD-2: S-PRG fillers 18.4 wt%; SRD-3: S-PRG fillers 27.8 wt%; and SRD-6: S-PRG fillers 57.4 wt%) were prepared, and mineral trioxide aggregate (MTA) was used as control (n = 8). Direct pulp capping was performed on rats that were sacrificed for further evaluation 2 or 4 weeks after the operation. The pulp tissue disorganization (PTD), inflammatory cell infiltration (ICI), and reparative dentin formation were histopathologically evaluated; the data were statistically analyzed using the Kruskal-Wallis and the Mann-Whitney U tests.

RESULTS

The histopathological evaluation of SRD-1-treated test animals 2 weeks post-operation revealed inferior PTD and ICI when compared with that of MTA. Even 4 weeks after the operation in SRD-1- and SRD-2-treated rats, the PTD and ICI were inferior when compared with those of MTA. The dental specimens of SRD-0 and MTA showed orthodentin formation, whereas SRD-treated test animals showed osteodentin formation at a position slightly deeper than the site of the pulpal exposure.

SIGNIFICANCE

The reparative dentin formed by SRD-0 and MTA was genuine, whereas that formed by SRD-3 and SRD-6 was ossified and ectopic. SRD may have the potential to be utilized clinically as a direct pulp capping material.

Artesunate promotes osteoblast differentiation through miR-34a/DKK1 axis

BACKGROUND

Osteoporosis is characterised by impairment of microarchitecture and bone mass. Therapeutic strategy promoting osteoblast differentiation is considered as a promising direction for the treatment of osteoporosis. Artesunate (ART) is related to osteoporosis, but the relationship between ART and osteogenic differentiation is still unknown.

METHODS

Cells proliferation were measured by MTT, ALP activity assay and Alizarin Red S staining were used to assess osteogenic differentiation of hBMSCs. Western blotting and qRT-PCR were applied for measuring expression of protein and mRNA, respectively. The relationship between miR-34a and Dickkopf-1 (DKK1) was detected by dual luciferase reporter assay.

RESULTS

The expression of osteoblasts differentiation related proteins (Runx2, OCN, and OPN) were significantly increased by ART. And ART accelerates the osteoblasts differentiation of hBMSCs through promoting Wnt signaling pathway by DKK1 inhibition. Significant higher expression of miR-34a and lower expression of DKK1 could be induced by ART. We firstly proved that miR-34a could bind DKK1 specifically.

CONCLUSION

ART could promote osteoblast differentiation through miR-34a/DKK1/Wnt pathway. Therefore, our findings may provide a new thought for the treatment of osteoporosis by ART through osteoblast differentiation promotion.

Melatonin Attenuates AlCl3-Induced Apoptosis and Osteoblastic Differentiation Suppression by Inhibiting Oxidative Stress in MC3T3-E1 Cells

Aluminum (Al) inhibits osteoblast-mediated bone formation by oxidative stress, resulting in Al-induced bone disease. Melatonin (MT) has received extensive attention due to its antioxidant and maintenance of bone health effect. To evaluate the protective effect and mechanism of MT on AlCl₃-induced osteoblast dysfunction, MC3T3-E1 cells were treated with MT (100 μM) and/or AlCl₃ (8 μM). First, MT alleviated AlCl₃-induced osteoblast dysfunction, presenting as the reduced apoptosis rate as well as increased cell viability, alkaline phosphatase (ALP) activity, and type I collagen (COL-1) level. Then, MT significantly attenuated AlCl₃-induced oxidative stress, presenting as the reduced reactive oxygen species and 8-hydroxy-2'-deoxyguanosine levels as well as increased glutathione level and superoxide dismutase activity. Finally, MT protected MC3T3-E1 cells against p53-dependent apoptosis and differentiation suppression, as assessed by Caspase-3 activity, protein levels of p53, Bcl-2-associated X protein (Bax), B cell lymphoma gene 2 (Bcl-2), cytosolic Cytochrome c, Runt-related transcription factor 2 (Runx2), and Osterix, as well as the mRNA levels of Bax, Bcl-2, Runx2, Osterix, ALP, and COL-1. Overall, our findings demonstrate MT attenuates AlCl₃-induced apoptosis and osteoblastic differentiation suppression by inhibiting oxidative stress in MC3T3-E1 cells.

Aluminium toxicosis: a review of toxic actions and effects

Aluminium (Al) is frequently accessible to animal and human populations to the extent that intoxications may occur. Intake of Al is by inhalation of aerosols or particles, ingestion of food, water and medicaments, skin contact, vaccination, dialysis and infusions. Toxic actions of Al induce oxidative stress, immunologic alterations, genotoxicity, pro-inflammatory effect, peptide denaturation or transformation, enzymatic dysfunction, metabolic derangement, amyloidogenesis, membrane perturbation, iron dyshomeostasis, apoptosis, necrosis and dysplasia. The pathological conditions associated with Al toxicosis are desquamative interstitial pneumonia, pulmonary alveolar proteinosis, granulomas, granulomatosis and fibrosis, toxic myocarditis, thrombosis and ischemic stroke, granulomatous enteritis, Crohn's disease, inflammatory bowel diseases, anemia, Alzheimer's disease, dementia, sclerosis, autism, macrophagic myofasciitis, osteomalacia, oligospermia and infertility, hepatorenal disease, breast cancer and cyst, pancreatitis, pancreatic necrosis and diabetes mellitus. The review provides a broad overview of Al toxicosis as a background for sustained investigations of the toxicology of Al compounds of public health importance.

Autophagy Protects MC3T3-E1 Cells upon Aluminum-Induced Apoptosis

Aluminum (Al) exposure has adverse effects on osteoblasts, and the effect might be through autophagy-associated apoptosis. In this study, we showed that aluminum trichloride (AlCl₃) could induce autophagy in MC3T3-E1 cells, as demonstrated by monodansylcadaverine (MDC) staining and the expressions of the ATG3, ATG5, and ATG9 genes. We found AlCl₃ inhibited MC3T3-E1 cell survival rate and caused apoptosis, as evidenced by CCK-8 assay, Annexin V/PI double staining, and increased expressions of Bcl-2, Bax, and Caspase-3 genes. In addition, increased autophagy induced by rapamycin further attenuated the MC3T3-E1 cell apoptosis rate after AlCl₃ exposure. These results support the hypothesis that autophagy plays a protective role in impeding apoptosis caused by AlCl₃. Activating autophagy may be a strategy for treatment of Al-induced bone disease.

Water-soluble factors eluated from surface pre-reacted glass-ionomer filler promote osteoblastic differentiation of human mesenchymal stem cells

Surface pre-reacted glass‑ionomer (S‑PRG)-containing dental materials, including composite and coating resins have been used for the restoration and/or prevention of dental cavities. S‑PRG is known to have the ability to release aluminum, boron, fluorine, silicon, and strontium ions. Aluminum ions are known to be inhibitors whereas boron, fluorine, silicon, and strontium ions are known to be promoters of mineralization, via osteoblasts. However, it remains to be clarified how an aqueous eluate obtained from S‑PRG containing these ions affects the ability of mesenchymal stem cells (MSCs), which are known to be present in dental pulp and bone marrow, to differentiate into osteogenic cell types. The present study demonstrated that 200‑ to 1,000‑fold‑diluted aqueous eluates obtained from S‑PRG significantly upregulated the mRNA expression level of the osteogenic differentiation marker alkaline phosphatase in human MSCs (hMSCs) without exhibiting the cytotoxic effect. In addition, the 500‑ to 1,000‑fold‑diluted aqueous eluates obtained from S‑PRG significantly and clearly promoted mineralization of the extracellular matrix of hMSCs. It was additionally demonstrated that hMSCs cultured on the cured resin composites containing S‑PRG fillers exhibited osteogenic differentiation in direct correlation with the weight percent of S‑PRG fillers. These results strongly suggested that aqueous eluates of S‑PRG fillers promoted hard tissue formation by hMSCs, implicating that resins containing S‑PRG may act as a useful biomaterial to cover accidental exposure of dental pulp.

Aluminum Trichloride Inhibited Osteoblastic Proliferation and Downregulated the Wnt/β-Catenin Pathway

Aluminum (Al) exposure inhibits bone formation. Osteoblastic proliferation promotes bone formation. Therefore, we inferred that Al may inhibit bone formation by the inhibition of osteoblastic proliferation. However, the effects and molecular mechanisms of Al on osteoblastic proliferation are still under investigation. Osteoblastic proliferation can be regulated by Wnt/β-catenin signaling pathway. To investigate the effects of Al on osteoblastic proliferation and whether Wnt/β-catenin signaling pathway is involved in it, osteoblasts from neonatal rats were cultured and exposed to 0, 0.4 mM (1/20 IC₅₀), 0.8 mM (1/10 IC₅₀), and 1.6 mM (1/5 IC₅₀) of aluminum trichloride (AlCl₃) for 24 h, respectively. The osteoblastic proliferation rates; Wnt3a, lipoprotein receptor-related protein 5 (LRP-5), T cell factor 1 (TCF-1), cyclin D1, and c-Myc messenger RNA (mRNA) expressions; and p-glycogen synthase kinase 3β (GSK3β), GSK3β, and β-catenin protein expressions indicated that AlCl₃ inhibited osteoblastic proliferation and downregulated Wnt/β-catenin signaling pathway. In addition, the AlCl₃ concentration was negatively correlated with osteoblastic proliferation rates and the mRNA expressions of Wnt3a, c-Myc, and cyclin D1, while the osteoblastic proliferation rates were positively correlated with mRNA expressions of Wnt3a, c-Myc, and cyclin D1. Taken together, these findings indicated that AlCl₃ inhibits osteoblastic proliferation may be associated with the inactivation of Wnt/β-catenin signaling pathway.

Inhibition of bone formation in rats by aluminum exposure via Wnt/β-catenin pathway

The previous research found that aluminum trichloride (AlCl₃) inhibited rat osteoblastic differentiation through inactivation of Wnt/β-catenin signaling pathway in vitro. On that basis, the experiment in vivo was conducted in this study. Rats were orally exposed to 0 (control group) and 0.4 g/L AlCl₃ (AlCl₃-treated group) for 30, 60, 90 or 120 days, respectively. We found that mRNA expressions of type I collagen and insulin-like growth factor-1, mRNA and protein expressions of Runx2 and survivin, ratio of p-GSK3β/GSK3β and protein expression of β-catenin were all decreased, whereas the mRNA and protein expressions Dkk1 and sFRP1 and the mRNA expressions and activity of Caspase-3 were increased in the AlCl₃-treated group compared with the control group with time prolonged. These results suggest that AlCl₃ inhibits bone formation and induces bone impairment by inhibiting the Wnt/β-catenin signaling pathway in young growing rats.

Inhibition of osteoblast differentiation by aluminum trichloride exposure is associated with inhibition of BMP-2/Smad pathway component expression

Bone morphogenetic protein-2 (BMP-2)/Smad signaling pathway plays an important role in regulating osteoblast (OB) differentiation. OB differentiation is a key process of bone formation. Aluminum (Al) exposure inhibits bone formation and causes Al-induced bone disease. However, the mechanism is not fully understood. To investigate whether BMP-2/Smad signaling pathway is associated with OB differentiation in aluminum trichloride (AlCl₃)-treated OBs, the primary rat OBs were cultured and exposed to 0 (control group, CG), 1/40 IC₅₀ (low-dose group, LG), 1/20 IC₅₀ (mid-dose group, MG), and 1/10 IC₅₀ (high-dose group, HG) of AlCl₃ for 24 h, respectively. We found that the expressions of OB differentiation markers (Runx-2, Osterix and ALP) and BMP-2/Smad signaling pathway components (BMP-2, BMPR-IA, p-BMPR-IA, BMPR-II, p-Smad1/5/8 and p-Smad1/5/8/4) were all decreased in AlCl₃-treated OBs compared with the CG. These results indicated that inhibition of OB differentiation by AlCl₃ was associated with inhibition of BMP-2/Smad pathway component expression. Our findings provide a novel insight into the mechanism of AlCl₃-induced bone disease.

Ginsenoside Rb1 alleviates aluminum chloride-induced rat osteoblasts dysfunction

Osteoblasts dysfunction, induced by aluminum (Al), plays a critical role in the osteoporosis etiology. Ginsenoside Rb1 (Rb1) has the therapeutic properties for osteoporosis. This study aimed to assess the efficiency of Rb1 in ameliorating Al-induced osteoblasts dysfunction. The osteoblasts were divided into four groups: Rb1-treated group (RG, 0.0145mg/mL Rb1), control group (CG, 0), AlCl₃-treated group (AG, 0.126mg/mL AlCl₃·6H₂O), AlCl₃+Rb1-treated group (ARG, 0.0145mg/mL Rb1 and 0.126mg/mL AlCl₃·6H₂O). After 24h of culture, the osteoblasts viability, the transforming growth factor-β1 (TGF-_β1), bone morphogenetic protein-2 (BMP-2), the insulin-like growth factor I (IGF-I), core-binding factor α1 (Cbfα1) mRNA expressions, glutathione perioxidase (GSH-P_x) and superoxide dismutase (SOD) activities, and reactive oxygen species (ROS) concentration were determined. The osteoblasts ultrastructural features were also observed. In the ARG, the osteoblasts viability, TGF-_β1, BMP-2, IGF-I and Cbfα1 mRNA expressions and the GSH-P_x and SOD activities were significantly increased, the ROS concentration was significantly decreased, and osteoblasts histology lesion was attenuated compared with the AG. These results demonstrated that Rb1 could significantly reverse osteoblasts viability and osteoblasts growth regulation factor, inhibit oxidative stress, and attenuate histology lesion in the osteoblasts with AlCl₃. These results indicate that Rb1 can effectively alleviate the AlCl₃-induced osteoblasts dysfunction.