Saos-2 Cell Viability Research Articles

Exploring the Anti-Cancer Potential of Hispidin: A Comprehensive in Silico and in Vitro Study on Human Osteosarcoma Saos2 Cells.

Hispidin was initially discovered in basidiomycete Inonotus hispidus (Bull.) P. Karst and this extraordinary compound possesses immense potency and can be extracted from the wild mushroom through specialized bioreactor cultivation techniques. In our study, we isolated it from Inonotus hispidus (Bull.) P. Karst., with a yield of 3.6 %. We identified and characterized hispidin through the implementation of spectroscopic techniques such as FTIR, NMR, and MS. Additionally, we utilized Thermogravimetric Analysis for thermal characterization of the compound. Computational studies based on DFT were performed to investigate the molecular structure, electronic properties, and chemical reactivity of hispidin. PASS analysis for hispidin demonstrated that 19 of them are anti-neoplastic activities. The Pharmacology prediction of hispidin confirm that it is not toxic, non-carcinogenesis with a good human intestinal absorption. The effect of hispidin on the viability of bone cancer cells was evaluated by MTT assay. The results showed that hispidin significantly reduced SaoS2 cell viability in a dose-dependent manner. Molecular docking was carried out using five targets related to bone cancer to determine the interactions between hispidin and the studied proteins. The results demonstrate that hispidin is a good inhibitor for the five targets. Dynamic simulation shows a good stability of the complex hispidin-protein.

Impact of scandium and terbium on the mechanical properties, corrosion behavior, and biocompatibility of biodegradable Mg-Zn-Zr-Mn alloys

Magnesium (Mg)-based bone implants degrade rapidly in the physiological environment of the human body which affects their structural integrity and biocompatibility before adequate bone repair. Rare earth elements (REEs) have demonstrated their effectiveness in tailoring the corrosion and mechanical behavior of Mg alloys. This study methodically investigated the impacts of scandium (Sc) and terbium (Tb) in tailoring the corrosion resistance, mechanical properties, and biocompatibility of Mg–0.5Zn–0.35Zr–0.15Mn (MZZM) alloys fabricated via casting and hot extrusion. Results indicate that addition of Sc and Tb improved the strength of MZZM alloys via grain size reduction and solid solution strengthening mechanisms. The extruded MZZM–(1–2)Sc–(1–2)Tb (wt.%) alloys exhibit compressive strengths within the range of 336–405 MPa, surpassing the minimum required strength of 200 MPa for bone implants by a significant margin. Potentiodynamic polarization tests revealed low corrosion rates of as–cast MZZM (0.25 mm/y), MZZM–2Tb (0.45 mm/y), MZZM–1Sc–1Tb (0.18 mm/y), and MZZM–1Sc–2Tb (0.64 mm/y), and extruded MZZM (0.17 mm/y), MZZM–1Sc (0.15 mm/y), MZZM-2Sc (0.45 mm/y), MZZM-1Tb (0.17 mm/y), MZZM-2Tb (0.10 mm/y), MZZM–1Sc-1Tb (0.14 mm/y), MZZM-1Sc-2Tb (0.40 mm/y), and MZZM–2Sc–2Tb (0.51 mm/y) alloys, which were found lower compared to corrosion rate of high-purity Mg (∼1.0 mm/y) reported in the literature. Furthermore, addition of Sc, or Tb, or Sc and Tb to MZZM alloys did not adversely affect the viability of SaOS2 cells, but enhanced their initial cell attachment, proliferation, and spreading shown via polygonal shapes and filipodia. This study emphasizes the benefits of incorporating Sc and Tb elements in MZZM alloys, as they effectively enhance corrosion resistance, mechanical properties, and biocompatibility simultaneously.

Genistein Induces Antiproliferative Activity and Apoptosis in Human Osteosarcoma Saos-2 Cells.

Genistein (4', 5, 7-trihydroxyisoflavone) and daidzein (4', 7-dihydroxyisoflavone) are isoflavones derived from soybean and have anti-cancer effects in various cells. However, the effects of genistein and daidzein on the human osteosarcoma cell line Saos-2 has not been investigated before. Human osteosarcoma Saos-2 cells were treated with genistein for 24 and 48 hours. Cytotoxicity and apoptosis were measured. Genistein significantly inhibited proliferation of Saos-2 cells stronger than daidzein in a dose-dependent manner (0 to 80 μM). Genistein also significantly suppressed Saos-2 cell viability in a dose-dependent manner (0 to 100 μM). In contrast, daidzein did not affect Saos-2 cell viability. Real-time PCR revealed that genistein caused G1-arrest by increasing the expression of p21 and p27 mRNAs in Saos-2 cells. In addition, genistein induced apoptosis through the up-regulation of effector caspase-3/7 activity in Saos-2 cells. Genistein also enhanced initiator caspase-9 and TNF-α mRNA expression in cells. Genistein may inhibit proliferation through the up-regulation of p21 and p27 and viability by inducing apoptosis in Saos-2 cells.

Bioactive Glasses Containing Strontium or Magnesium Ions to Enhance the Biological Response in Bone Regeneration.

The non-surgical treatments are being required to reconstruct damaged tissue, prioritizing our body's natural healing process. Thus, the use of bioactive materials such as bioactive glass has been studied to support the repair and restoration of hard and soft tissue. Thus, in this work Bioglass 45S5 was developed, adding 1 and 2%mol of SrO or MgO and the physical and biological properties were evaluated. The addition of MgO and SrO at the studied concentrations promoted the slight increase in non-bridging oxygens number, observed through the temperature shift in phase transitions to lower values compared to Bioglass 45S5. The insertion of the ions also showed a positive effect on Saos-2 cell viability, decreasing the cytotoxic of Bioglass 45S5. Besides the Ca/P ratio on the pellets surface demonstrating no evidence of higher reactivity between Bioglass 45S5 and Bioglass with Sr and Mg, micrographs show that at 24 h the Ca/P rich layer is denser than in Bioglass 45S5 after the contact with simulated body fluid. The samples with Sr and Mg show a higher antibacterial effect compared to Bioglass 45S5. The addition of the studied ions may benefit the biological response of Bioglass 45S5 in dental applications as scaffolds or coatings.

Exploring the molecular mechanism of linagliptin in osteosarcoma cell lines for anti-cancer activity

BackgroundFinding new applications for widely used current drugs is a fast and effective technique for discovering new anticancer chemicals. Osteosarcoma (OS), the most prevalent form of bone cancer, has several side effects that significantly lower patients’ quality of life. This study aims to systematically examine the anti-cancer activity of linagliptin (LG) in the osteosarcoma cell line Saos-2. MethodsMTT assays and flow cytometry were used to assess cell viability and apoptosis, respectively. qPCR array experiments were carried out to determine target gene expressions and explain the molecular mechanism of LG’s action. ResultsLinagliptin treatment significantly decreased the viability of Saos-2 cells and hFOB1.19 cells (p < 0.001). The treatment also induced increased apoptotic effects in both Saos-2 cells (p < 0.001) and hFOB1.19 cells (p < 0.05). qPCR assays were conducted to assess cancer pathway analysis after applying specific quantities of LG to Saos-2 and hFOB1.19 cells. ConclusionThe findings of this study demonstrate that LG inhibits the proliferation of Saos-2 cells and induces cell death. LG supports cell death by suppressing the expression of specific genes involved in cancer pathways.

Fabrication, Structural and Biological Characterization of Zinc-Containing Bioactive Glasses and Their Use in Membranes for Guided Bone Regeneration.

Polymeric membranes are widely used in guided bone regeneration (GBR), particularly in dentistry. In addition, bioactive glasses can be added to the polymers in order to develop a matrix that is osteoconductive and osteoinductive, increasing cell adhesion and proliferation. The bioactive glasses allow the insertion into its network of therapeutic ions in order to add specific biological properties. The addition of zinc into bioactive glasses can promote antibacterial activity and induce the differentiation and proliferation of the bone cells. In this study, bioactive glasses containing zinc (0.25, 0.5, 1 and 2 mol%) were developed and structurally and biologically characterized. The biological results show that the Zn-containing bioactive glasses do not present significant antibacterial activity, but the addition of zinc at the highest concentration does not compromise the bioactivity and promotes the viability of Saos-2 cells. The cell culture assays in the membranes (PCL, PCL:BG and PCL:BGZn2) showed that zinc addition promotes cell viability and an increase in alkaline phosphatase (ALP) production.

From corrosion behavior to radiation response: A comprehensive biocompatibility assessment of a CoCrMo medium entropy alloy for utility in orthopedic and dental implants

This paper presents a thorough biocompatibility evaluation of a CoCrMo medium entropy alloy to assess its potential to be utilized in orthopedic and dental implants. For this purpose, a wide range of systematic experiments were carried out, including static immersion, cell culture and radiation experiments. In particular, chemical biocompatibility and ion release behavior of the CoCrMo alloy were studied by carrying out static immersion experiments in artificial saliva (AS), simulated body fluid (SBF) and fetal bovine serum (FBS). Detailed analysis of the surfaces of the tested samples demonstrated that both passive oxide layer and hydroxyapatite formation occur on the CoCrMo sample surfaces immersed in AS, SBF and FBS for 28 days. The response of living cells to the CoCrMo alloy was tested utilizing cell culture experiments, and the evidence of Saos-2 cell viability and proliferation supported the static biocompatibility experiment results, indicating the potential of the CoCrMo alloy to be utilized as an orthopedic implant material. Finally, the effect of a CoCrMo implant on the actual radiation dose induced upon malignant tissue in the vicinity of the implant during a radiotherapy was evaluated by applying medical grade radiation to water phantoms circumventing CoCrMo samples. The results showed that the radiation accumulation in the tissue within the immediate vicinity of a CoCrMo implant would be a minimum, eliminating some of the undesired side effects. Overall, the results of the three different types of experiments reported in this paper have clearly demonstrated that the CoCrMo medium entropy alloy investigated in this study has significant potential to be utilized as a safe implant material in dental and orthopedic implants.

In Vitro Molecular Study of Titanium-Niobium Alloy Biocompatibility.

Titanium dental implants have common clinical applications due to their biocompatibility, biophysical and biochemical characteristics. Although current titanium is thought to be safe and beneficial for patients, there are several indications that it may release toxic metal ions or metal nanoparticles from its alloys into the surrounding environment, which could lead to clinically relevant complications including toxic reactions as well as immune dysfunctions. Hence, an adequate selection and testing of medical biomaterial with outstanding properties are warranted. This study was designed to explore the biocompatibility of smooth titanium-niobium alloy (S_TiNb) versus smooth titanium commercially pure (S_TiCp)—a reference in implantology. All experiments were performed in vitro using human osteoblast-like SaOs-2 and monocyte THP-1 cell lines as models. Cell adhesion and growth morphology were determined by scanning electron microscopy, while cell viability was evaluated using WST-1 assay. Because niobate anions or niobium nanoparticles can be released from implants during biomaterial-cell interaction, potential immunotoxicity of potassium niobate (KNbO3) salt was evaluated by examining both metabolic activity and transcriptomic profiling of treated THP-1 monocytes. The main findings of this study are that S_TiCp and S_TiNb discs do not show an impact on the proliferation and viability of SaOs-2 cells compared to polystyrene surfaces, whereas a significant decrease in THP-1 cells’ viability and metabolic activity was observed in the presence of S_TiNb discs compared to the control group. However, no significant changes were found neither at the metabolic activity nor at the transcriptomic level of THP-1 monocytes exposed to KNbO3 salt, suggesting that niobium has no effect on the immune system. Overall, these data imply a possible toxicity of S_TiNb discs toward THP-1 cells, which may not be directly related to niobium but perhaps to the manufacturing process of titanium-niobium alloy. Thus, this limitation must be overcome to make titanium alloy an excellent material for medical applications.

Effects of Various Processing Parameters on Mechanical Properties and Biocompatibility of Fe-based Bulk Metallic Glass Processed via Selective Laser Melting at Constant Energy Density

The unique properties of bulk metallic glass (BMG) render it an excellent material for bone-implant applications. BMG samples are difficult to produce directly because of the critical cooling rate of molding. Advancements in additive manufacturing technologies, such as selective laser melting (SLM), have enabled the development of BMG. The successful production of materials via SLM relies significantly on the processing parameters; meanwhile, the overall energy density affects the crystallization and, thus, the final properties. Therefore, to further determine the effects of the processing parameters, SLM is performed in this study to print Fe-based BMG with different properties three dimensionally using selected processing parameters but a constant energy density. The printed amorphous Fe-based BMG outperforms the typical 316 L stainless steel (316 L SS) in terms of mechanical properties and corrosion resistance. Moreover, observations from nanoindentation tests indicate that the hardness and elastic modulus of the Fe-based BMG can be customized explicitly by adjusting the SLM processing parameters. Indirect cytotoxicity results show that the Fe-based BMG can enhance the viability of SAOS2 cells, as compared with 316 L SS. These intriguing results show that Fe-based BMG should be investigated further for orthopedic implant applications.

Thymoquinone Augments Methotrexate-Induced Apoptosis on Osteosarcoma Cells.

Osteosarcoma (OS) as the most frequent primary bone malignancy in children and adolescents has a short survival rate in advanced stages. Alternative herbal medicines with fewer side effects or the potency to protect common therapy's side effects can be helpful in combinational therapies. Herein, we aim to explore the effects of Thymoquinone (TQ) combined with Methotrexate (MTX) on Saos-2 cells apoptosis. The effects of TQ and MTX alone or in combination on Saos-2 cell viability were measured by MTT assay. Real-time PCR was applied for the measurement of Bax, BCL-2, and caspase-9 mRNA expression. Apoptosis evaluation was conducted by flow cytometry. TQ improves the cytotoxic effects of MTX on Saos-2 cells proliferation at lower doses. Indeed, the IC50 of MTX decreased from 26 μM to 15 μM when it combined with TQ. TQ and MTX can induce the expression level of pro-apoptotic factors, Bax and caspase-9 while inhibiting anti-apoptotic protein BCL-2. Moreover, the combination of TQ and MTX potentiates apoptosis to 73%, compared to either TQ (48%) or MTX (53%) treated cells. The co-treatment of TQ and MTX is associated with the up-regulation of apoptotic factors and down-regulation of anti-apoptotic factors, conducting apoptosis aggravation and OS cell death.

The Effect of TQ and Cis in OS.

Osteosarcoma (OS) is a primary bone sarcoma with a high recurrence rate and poorer prognosis. The application of natural agents in combinational therapies can increase the efficacy of treatment and decrease the side effects. Herein, we aimed to evaluate the effects of Thymoquinone (TQ) combined with Cisplatin on apoptosis and its underlying mechanisms in the Saos-2 cells. The effects of TQ and Cisplatin on Saos-2 cell viability were measured using an MTT assay. Western blotting was applied for the measurement of γH2AX protein expression. The expression levels of 8-Hydroxy-2'-deoxyguanosine (8-oxo-dG) were evaluated by enzyme-linked immunosorbent assay (ELISA). DCFH-DA fluorescence dye was used to detect reactive oxygen species (ROS) formation. For evaluation of apoptosis, flow cytometry was employed. TQ dramatically promotes the cytotoxic effects of Cisplatin. TQ considerably enhanced the expression levels of 8-oxo-dG and γ-H2AX in Saos-2 cells. After TQ treatment, ROS levels were increased; furthermore, TQ treatment resulted in the potentiation of Cisplatin-induced apoptosis in Saos-2 cells compared to either TQ or Cisplatin treated cells. In general, TQ plus Cisplatin resulted in potentiated cellular cytotoxicity by increasing ROS level and inducing oxidative DNA damage, leading to the potent induction of apoptosis in tumor cells.

An investigation of the effect of surface characterization on Saos-2 cell proliferation after coating of titanium alloy surfaces by a selective laser melting process

Pure titanium alloys are commonly employed in construction of dental implants, given their advantageous features including resistance to corrosion, mechanical strength, flexibility, and bioavailability. The purpose of this study was to evaluate the surface characteristics of Ti6Al4V alloy disks upon sand-blasted, large-grit acid-etching, and/or selective laser melting applications and to assess whether and how these surface modifications affect the attachment, viability, metabolic activity, and osteoblastic differentiation of Saos-2 osteosarcoma cells. We manufactured Ti6Al4V alloy disks and divided them into four groups (non-treated, SLA-treated, Ti6Al4V ELI alloy-coated (SLM treated), and SLM+SLA-treated). The topographic analysis was carried using AFM and SEM and chemical content was evaluated by EDX . EDS. Adherence and viability of Saos-2 cells seeded onto disks were investigated via SEM and fluorescent microscopy. To assess the metabolic activity of Saos-2 cells, MTT assay was conducted and the osteoblastic differentiation interpreted via monitoring alkaline phosphatase activity. According to data acquired using AFM and SEM, the control group had the smoothest surfaces, with a lower Ra value. The roughest surface was obtained with SLM and SLA dual-treated disks. The osteoblastic activity of Saos-2 cells on the surface of dual-treated disks was higher than the other groups. Therefore, the surface of SLM+SLA-treated disks conferred a suitable environment for Saos-2 cells to adhere, proliferate, and show higher metabolic activity. We concluded that Ti6Al4V alloy disks covered with Ti6Al4V ELI alloy and subjected to SLA surface treatment may be promising to manufacture dental implants with improved adaptability, bioavailability, and osseointegration. • Surface topographies of Ti6Al4V disks subjected to various coatings were evaluated using AFM and SEM. • MTT and ALP assays were performed to reveal osteoblastic differentiation onto Saos-2 cells planted Ti6Al4V disks. • Cell adhesion increased in direct proportion to the thickness of the Ti6Al4V disks. • SLM+SLA treatment is a preferable surface construction since the morphology of osteoblasts is positively affected. • The success of dental implant surface is related to its chemical properties along its micro-morphological nature.

Enhanced Generation of Reactive Species by Cold Plasma in Gelatin Solutions for Selective Cancer Cell Death.

Atmospheric pressure plasma jets generate reactive oxygen and nitrogen species (RONS) in liquids and biological media, which find application in the new area of plasma medicine. These plasma-treated liquids were demonstrated recently to possess selective properties on killing cancer cells and attracted attention toward new plasma-based cancer therapies. These allow for local delivery by injection in the tumor but can be quickly washed away by body fluids. By confining these RONS in a suitable biocompatible delivery system, great perspectives can be opened in the design of novel biomaterials aimed for cancer therapies. Gelatin solutions are evaluated here to store RONS generated by atmospheric pressure plasma jets, and their release properties are evaluated. The concentration of RONS was studied in 2% gelatin as a function of different plasma parameters (treatment time, nozzle distance, and gas flow) with two different plasma jets. Much higher production of reactive species (H2O2 and NO2-) was revealed in the polymer solution than in water after plasma treatment. The amount of RONS generated in gelatin is greatly improved with respect to water, with concentrations of H2O2 and NO2- between 2 and 12 times higher for the longest plasma treatments. Plasma-treated gelatin exhibited the release of these RONS to a liquid media, which induced an effective killing of bone cancer cells. Indeed, in vitro studies on the sarcoma osteogenic (SaOS-2) cell line exposed to plasma-treated gelatin led to time-dependent increasing cytotoxicity with the longer plasma treatment time of gelatin. While the SaOS-2 cell viability decreased to 12%-23% after 72 h for cells exposed to 3 min of treated gelatin, the viability of healthy cells (hMSC) was preserved (∼90%), establishing the selectivity of the plasma-treated gelatin on cancer cells. This sets the basis for designing improved hydrogels with high capacity to deliver RONS locally to tumors.

β-catenin mediates fluoride-induced aberrant osteoblasts activity and osteogenesis

Excess fluoride in drinking water is an environmental issue of increasing worldwide concern, because of its adverse effect on human health. Skeletal fluorosis caused by chronic exposure to excessive fluoride is a metabolic bone disease characterized by accelerated bone turnover accompanied by aberrant activation of osteoblasts. It is not clear whether Wnt/β-catenin signaling, an important signaling pathway regulating the function of osteoblasts, mediates the pathogenesis of skeletal fluorosis. A cross-sectional case-control study was conducted in Tongyu County, Jilin Province, China showed that fluoride stimulated the levels of OCN and OPG, resulting in accelerated bone turnover in patients with skeletal fluorosis. To investigate the influence of fluoride on Wnt/β-catenin signaling pathway, 64 male BALB/c mice were allotted randomly to four groups and treated with deionized water containing 0, 55, 110 and 221 mg/L NaF for 3 months, respectively. The results demonstrated that fluoride significantly increased mouse cancellous bone formation and the protein expression of Wnt3a, phospho-GSK3β (ser 9) and Runx2. Moreover, partial correlation analysis indicated that there was no significant correlation between fluoride exposure and Runx2 protein levels, after adjusting for β-catenin, suggesting that β-catenin might play a crucial role in fluoride-induced aberrant osteogenesis. In vivo, viability of SaoS2 cells was significantly facilitated by 4 mg/L NaF, and fluoride could induce the abnormal activation of Wnt/β-catenin signaling, the expression of its target gene Runx2 and significantly increased Tcf/Lef reporter activity. Importantly, inhibition of β-catenin suppressed fluoride-induced Runx2 protein expression and the osteogenic phenotypes. Taken together, the present study provided in vivo and in vitro evidence reveals a potential mechanism for fluoride-induced aberrant osteoblast activation and indicates that β-catenin is the pivot molecule mediating viability and differentiation of osteoblasts and might be a therapeutic target for skeletal fluorosis.

Optimal red clover ethanolic extract by relative aggregated metric increases osteoblastic activity and nuclear factor kappa-B ligand gene expression in SaOS-2 cells

Age-related osteoporosis affects people of both genders at any age especially postmenopausal women. The manifestation of reduced bone strength leads to increased risk of bone fracture. Currently, many have sought for plant-based supplements for the management of bone health. Red clover (Trifolium pratense) contains phytoestrogenic isoflavones which are known to limit osteoclastic activity and reduce bone resorption. Our study aimed to optimize the condition for the preparation of red clover ethanolic extract to obtain highest yield while retaining the desired bioactivity. In this study, relative aggregated metric (RAM) was designed to ease the selection process of extraction formulation based on yield and SaOS-2 cell viability. The selected ethanolic red clover extract obtained from the optimum condition (RC-D) exerted high cell viability in SaOS-2 cells which is comparable to that of 17β-estradiol. RC-D also showed promising dose-dependent alkaline phosphatase activity in SaOS-2 cells. Besides, the RANKL, OPG, ALP and Col-A gene expression analysis revealed that RC-D potentially halts the osteoclastic activity via downregulation of RANKL mRNA expression. In short, RC-D prepared and selected via RAM developed in this study has shown promising anti-osteoporotic characteristics in SaOS-2 cells and might be considered as a functional food for bone quality management.

Designing laser-modified surface structures on titanium alloy custom medical implants using a hybrid manufacturing technology.

The hybrid technology combines an efficient material-removal process and implant surface treatment by the laser reducing time of manufacture process compared to currently used machining technologies. It also permits precise structuring of the implant material surface. Six structures of the Ti6Al4V ELI surface were designed and studied how the structure topography prepared with the hybrid technology affected the Escherichia coli adhesion to the surface and viability, as well as the growth, adhesion, and viability of human osteogenic Saos-2 cells cultured on the investigated surfaces. Results have confirmed that the microtopography of medical titanium alloy plays a beneficial role in bacterial adhesion and viability (number of bacteria found on reference surface: [5.9 ± 0.44] × 106 CFU/ml, sample no. 3: [8.8 ± 0.93] × 104 CFU/ml, and sample no. 5: [1.2 ± 0.23] × 107 CFU/ml; CFU - Colony Forming Unit). All tested structured surfaces enabled good cell attachment and proliferation of Saos-2 cells (viability of Saos-2 cells [% of control] for reference surface: 81.93%; sample no. 3: 75% and sample no. 5: 100%). Transcriptome analysis of genes commonly expressed in the process of osseointegration demonstrated that the use of hybrid technology allows designing structures that enhance osseointegration but it should be coupled with other methods of preventing bacterial growth, or with a different strategy to limit microbial colonization with the satisfactory osseointegration potential.

A comparative study of monoaxial and coaxial PCL/gelatin/Poloxamer 188 scaffolds for bone tissue engineering

Structure of fibrous scaffolds varies depending on the electrospinning method and parameters which will define cell fate. In this study, monoaxial and coaxial electrospun PCL/gelatin/P-188 scaffolds were characterized in terms of morphology, chemistry, mechanical property, water retention, weight loss, porosity and release properties. Coaxial fibers supported duel release of model hydrophilic protein (Beta-lactoglobulin) and hydrophobic agent vitamin K2. Novel PCL/P-188(Shell):Gelatin/P-188(Core) coaxial scaffold had superior stability, average weight loss, no swelling behavior, controlled release of Beta-lactoglobulin and vitamin K2, enhanced Saos-2 cell viability and ALP activity and could be a good candidate as a bone tissue scaffold.

Palmitic acid induces human osteoblast-like Saos-2 cell apoptosis via endoplasmic reticulum stress and autophagy.

Palmitic acid (PA) is the most common saturated long-chain fatty acid in food that causes cell apoptosis. However, little is known about the molecular mechanisms of PA toxicity. In this study, we explore the effects of PA on proliferation and apoptosis in human osteoblast-like Saos-2 cells and uncover the signaling pathways involved in the process. Our study showed that endoplasmic reticulum (ER) stress and autophagy are involved in PA-induced Saos-2 cell apoptosis. We found that PA inhibited the viability of Saos-2 cells in a dose- and time-dependent manner. At the same time, PA induced the expression of ER stress marker genes (glucose-regulated protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP)), altered autophagy-related gene expression (microtubule-associated protein 1 light chain 3 (LC3), ATG5, p62, and Beclin), promoted apoptosis-related gene expression (Caspase 3 and BAX), and affected autophagic flux. Inhibiting ER stress with 4-PBA diminished the PA-induced cell apoptosis, activated autophagy, and increased the expression of Caspase 3 and BAX. Inhibiting autophagy with 3-MA attenuated the PA and ER stress-induced cell apoptosis and the apoptosis-related gene expression (Caspase 3 and BAX), but seemed to have no obvious effects on ER stress, although the CHOP expression was downregulated. Taken together, our results suggest that PA-induced Saos-2 cell apoptosis is activated via ER stress and autophagy, and the activation of autophagy depends on the ER stress during this process.

Effect of addition of Si on microstructure, mechanical properties, bio-corrosion and cytotoxicity of Mg-6Al-1Zn alloy

Abstract The Mg-6Al-4Zn alloy was fabricated by mechanical alloying (MA) and hot pressing to serve as biodegradable metal implant. The influence of addition of 1% Si (mass fraction) on the microstructure, mechanical properties and bio-corrosion behavior of Mg-6Al-1Zn alloy was studied using X-ray diffractometry, transmission electron microscopy, compression test, as well as immersion, electrochemical test and MTT assay. The results showed that the addition of 1% Si to Mg-6Al-1Zn alloy led to the formation of fine Mg2Si phase with polygonal shape, and increased compressive strength, elongation and improved corrosion resistance. Furthermore, the cell viability of Saos-2 cells has been improved by addition of 1% Si to Mg-6Al-1Zn alloy. According to the results, the magnesium ions released in the methylthiazol tetrazolium (MTT) test have not shown any cell toxicity. All these indicated that the addition of 1% Si improved the properties of Mg-6Al-4Zn alloy for using as a biodegradable implant.

Ytterbium Oxide as Radiopacifier of Calcium Silicate-Based Cements. Physicochemical and Biological Properties.

This study evaluated physicochemical properties, cytotoxicity and bioactivity of MTA Angelus (MTA), calcium silicate-based cement (CSC) and CSC with 30% Ytterbium oxide (CSC/Yb2O3). Setting time was evaluated using Gilmore needles. Compressive strength was evaluated in a mechanical machine. Radiopacity was evaluated using radiographs of materials and an aluminum scale. Solubility was evaluated after immersion in water. Cell viability was evaluated by means of MTT assay and neutral red staining, and the mineralization activity by using alkaline phosphatase activity and Alizarin Red staining. The data were submitted to ANOVA, Tukey and Bonferroni tests (5% significance). The bioactive potential was evaluated by scanning electron microscopy. The materials presented similar setting time. MTA showed the lowest compressive strength. MTA and CSC/Yb2O3 presented similar radiopacity. CSC/Yb2O3 showed low solubility. Saos-2 cell viability tests showed no cytotoxic effect, except to 1:1 dilution in NR assay which had lower cell viability when compared to the control. ALP at 1 and 7 days was similar to the control. MTA and CSC had greater ALP activity at 3 days when compared to control. All the materials present higher mineralized nodules when compared with the control. SEM analysis showed structures suggesting the presence of calcium phosphate on the surface of materials demonstrating bioactivity. Ytterbium oxide proved to be a properly radiopacifying agent for calcium silicate-based cement since it did not affected the physicochemical and biological properties besides preserving the bioactive potential of this material.