Evaluation of Biodegradable Alloy Fe30Mn0.6N in Rabbit Femur and Cartilage through Detecting Osteogenesis and Autophagy.

Biodegradable iron alloy implants have become one of the most ideal possible candidates because of their biocompatibility and comprehensive mechanical properties. Iron alloy's impact on chondrocytes is still unknown, though. This investigation looked at the biocompatibility and degradation of the Fe30Mn0.6N alloy as well as how it affected bone formation and chondrocyte autophagy. In vivo implantation of Fe30Mn0.6N and Ti6Al4V rods into rabbit femoral cartilage and femoral shaft was carried out to evaluate the degradation of the alloy and the cartilage and bone response at different intervals. After 8 weeks of implantation, the cross-sectional area of the Fe30Mn0.6N alloys lowered by 50.79 ± 9.59%. More Ca and P element deposition was found on the surface Fe30Mn0.6N rods by using energy dispersive spectroscopy (EDS) and scanning electron microscopy (P < 0.05). After 2, 4, and 8 weeks of implantation, no evident inflammatory infiltration was seen in peri-implant cartilage and bone tissue of Fe30Mn0.6N and Ti6Al4V alloys. Also, implantation of Fe30Mn0.6N alloy promoted autophagy in cartilage by detecting expression of LC3-II compared with Ti6Al4V after implantation (P < 0.05). Fe30Mn0.6N alloy also stimulated early osteogenesis at the peri-implant interface compared with Ti6Al4V after implantation (P < 0.05). In the in vitro test, we found that low concentrations of Fe30Mn0.6N extracts had no influence on cell viability. 15% and 30% extracts of Fe30Mn0.6N could upregulate autophagy compared to the control group by detecting beclin-1, LC3, Atg3, and P62 on the basis of WB and IHC (P < 0.05). Also, the PI3K-AKT-mTOR signaling pathway mediated in the upregulation of autophagy of chondrocytes resulting in exposure to extract of Fe30Mn0.6N alloy. It is concluded that Fe30Mn0.6N showed degradability and biocompatibility in vivo and upregulated autophagy activity in chondrocytes.

Material properties of degradable alloy Fe-30Mn-0.6N and its effect on ferroptosis in synoviocytes.

Ferroalloy has shown potential as implant materials, but little attention has been paid to their effects on synovial tissue ferroptosis. This study aimed to examine the mechanical properties, degradability and biocompatibility of Fe-30Mn-0.6N alloy and effects of it on synovial tissue ferroptosis. Tensile testing showed that Fe-30Mn-0.6N alloys exhibited tensile strength of 487 ± 18 MPa, yield strength of 221 ± 10 MPa, elongation of 16.9 ± 0.3% and Young's modulus of 37.7 ± 1.3 GPa. In vivo experiments, the cross-sectional area of the Fe-30Mn-0.6N alloys decreased by 73.32 ± 12.73% after 8 weeks of implantation. The results of scanning electron microscopy (SEM) and surface elemental analysis (EDS) showed that the Fe-30Mn-0.6N alloys had more Ca, O, C and P element deposition (p < .05). After 2, 4 and 8 weeks of implantation, no inflammatory response was observed in peri-implant synovial tissue of Fe-30Mn-0.6N and Ti-6Al-4V alloys, and Fe-30Mn-0.6N alloys did not affect the expression of the ferroptosis inhibitory gene Glutathione peroxidase 4 (GPX4). Compared with the control group, 30% Fe-30Mn-0.6N alloy extracts did not affect the cell viability (p > .05) in vitro, and intracellular Fe2+ and the reactive oxygen species (ROS) was significantly reduced (p < .05). WB and PCR results showed that the 30% extracts increased the protein activity and mRNA expression of GPX4, FTH1 and SLC7A11 in synoviocytes, but had no effect on PTGS2 and p53. It is concluded that Fe-30Mn-0.6N had degradability and biocompatibility in peri-implant synovial tissue, and did not induce significantly ferroptosis in synoviocytes.

Effects of Estrogen on Proliferation and Apoptosis of Osteoblasts through Regulating GPER/AKT Pathway.

This experiment was carried out to study the effects of estrogen on the proliferation and apoptosis of osteoblasts through regulating the G protein-coupled estrogen receptor (GPER)/protein kinase B (AKT) pathway. For this aim, osteoblasts were cultured in vitro and divided into control group, estrogen group and inhibitor group after passage. The osteoblasts in the control group were cultured normally, estrogen intervention was made in the estrogen group and G15 inhibitor intervention was made in the inhibitor group. After intervention for 24 h, osteoblasts were collected for detection. The positive expression of GPER and the double-positive expression of Tom20/Lamp2 were detected via immunofluorescence assay. The protein expressions of GPER, AKT and phosphorylated (p)-AKT were detected via Western blotting. The mRNA expression of GPER was detected via qPCR. Moreover, the autophagosomes were observed under a transmission electron microscope, and the apoptosis and cell proliferation were detected via terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay and cell counting kit-8 (CCK8) assay, respectively. Results of the immunofluorescence assay revealed that the positive expression of GPER in the estrogen group was higher than that in the control group and inhibitor group (p<0.05), while the double-positive expression of Tom20/Lamp2 in the estrogen group was lower than that in control group and inhibitor group (p<0.05). According to the results of Western blotting, the relative protein expression of AKT had no differences among the three groups (p>0.05), while the relative protein expressions of GPER and p-AKT in the estrogen group were higher than those in the control group and inhibitor group (p<0.05). The results of qPCR showed that the relative mRNA expression of GPER in the estrogen group was higher than that in the control group and inhibitor group (p<0.05). There were a small number of autophagosomes in osteoblasts in the control group and inhibitor group, while the number of autophagosomes in osteoblasts was smaller in the estrogen group. Besides, the estrogen group had a remarkably lower apoptosis rate of osteoblasts than the control group and inhibitor group and a remarkably higher proliferation rate than the control group and inhibitor group. Then estrogen can inhibit the mitochondrial autophagy of osteoblasts by regulating the GPER/AKT pathway, thereby inhibiting apoptosis and promoting cell proliferation.

Microalgae cultivation using unsterilized cattle farm wastewater filtered through corn stover.

The aim of this study was to investigate the cultivation of Chlorella sp. (FACHB-8) and Kirchneriella obesa (FACHB-2104) using the unsterilized cattle farm wastewater (CFW) filtered through corn stover. Corn stover filtration effectively reduced the turbidity and suspended solids of CFW and improved the adaptability of microalgae to CFW. The yields of microalgae supplemented with filtered CFW were significantly higher than those of microalgae supplemented with unfiltered CFW-by 14%-57% (FACHB-8) and 12%-78% (FACHB-2104) and comparable to those with pure blue-green algae medium (BG11). The growth kinetics of microalgae conformed to the DoseResp model. A 3:6 ratio of filtered CFW to BG11 and an 8000 lx light intensity were optimal for achieving high microalgae production. Under optimum conditions, the maximal yields of FACHB-8 and FACHB-2104 were 1.26 and 1.22 g/L, respectively, and the removal efficiencies of nitrogen, phosphorus, and chemical oxygen demand exceeded 95%, 99%, and 82%, respectively.

Up-regulation of SIRT1 induced by 17beta-estradiol promotes autophagy and inhibits apoptosis in osteoblasts.

Osteoporosis is a common systemic skeletal metabolism disorder resulting in bone fragility and increased fracture risk. Silent information regulator factor 2 homolog 1 (SIRT1) is crucial in the regulation of several biological processes, including bone metabolism, autophagy, apoptosis, and aging. This study aimed to assess whether the up-regulation of SIRT1 induced by 17beta-estradiol (17ß-E2) could promote autophagy and inhibit apoptosis in osteoblasts via the AMPK-mTOR and FOXO3a pathways, respectively. The study found that 17ß-E2 (10-6 M) administration induced the up-regulation of SIRT1 in osteoblasts. Up-regulation of SIRT1 induced by 17ß-E2 increased the expression level of LC3, Beclin-1, Bcl-2, p-AMPK, FOXO3a but decreased caspase-3 and p-mTOR expression, and then promoted autophagy and inhibited apoptosis. More autophagosomes were observed under a transmission electron microscope (TEM) in 17ß-E2 and SRT1720 (a selective SIRT1 activator) co-treated group. When Ex527 (a SIRT1-specific inhibitor) was pretreated, the reversed changes were observed. Taken together, our findings demonstrated that the up-regulation of SIRT1 induced by 17ß-E2 could promote autophagy via the AMPK-mTOR pathway and inhibit apoptosis via the FOXO3a activation in osteoblasts, and SIRT1 might become a more significant target in osteoporosis treatment.

circRNA expression pattern and ceRNA network in the pathogenesis of aseptic loosening after total hip arthroplasty.

Increasing evidence has demonstrated that circular RNA (circRNA) exerts important function in the pathogenesis of some diseases. While, the contributions of circRNAs to aseptic loosening after total hip arthroplasty (THA) remain largely unknown. Our research is to explore the differentially expressed circRNAs (DEcircRNAs) and elucidate complex regulated mechanism of circRNAs in aseptic loosening. The DEcircRNAs were identified by RNA sequencing (RNA-seq) analysis. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was adopted to corroborate these DEcircRNAs. The potential function of circRNAs in aseptic loosening tissue was identified by competing endogenous RNA (ceRNA) analysis. Enrichment analysis was performed for target mRNAs and host genes of the DEcircRNAs by Gene Oncology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG). 257 DEcircRNAs were obtained from RNA-seq results. Following the RT-qPCR corroboration, 6 circRNAs (hsa_circ_0007482, hsa_circ_0005232, hsa_circ_0000994, hsa_circ_0000690, hsa_circ_0058092 and hsa_circ_0004496) were selected for further analysis. By circRNA-miRNA and miRNA-mRNA prediction, 6 circRNAs, 138 miRNAs and 1667 mRNAs were identified. Then, circRNA-miRNA-mRNA network was established. The result of GO and KEGG enrichment analysis suggested that the circRNAs were related with some biological functions and pathways of aseptic loosening. A novel pathogenesis and treatment strategy about aseptic loosening after THA was revealed from our study of circRNA-miRNA-mRNA network.