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Osteoarthritis (OA) is characterized by an imbalance between M1 and M2 polarized synovial macrophages. Quercetin has shown protective effects against OA by altering M1/M2‐polarized macrophages, but the underlying mechanisms remain unclear. In this study, rat chondrocytes were treated with 10 ng/mL of IL‐1β. To create M1‐polarized macrophages in vitro, rat bone marrow‐derived macrophages (rBMDMs) were treated with 100 ng/mL LPS. To mimic OA conditions observed in vivo, a co‐culture system of chondrocytes and macrophages was established. ATP release assays, immunofluorescence assays, Fluo‐4 AM staining, Transwell assays, ELISA assays, and flow cytometry were performed. Male adult Sprague–Dawley (SD) rats were used to create an OA model. Histological analyses, including H&E, and safranin O‐fast green staining were performed. Our data showed a quercetin‐mediated suppression of calcium ion influx and ATP release, with concurrent downregulation of TRPV1 and P2X7 in the chondrocytes treated with IL‐1β. Activation of TRPV1 abolished the quercetin‐mediated effects on calcium ion influx and ATP release in chondrocytes treated with IL‐1β. In the co‐culture system, overexpression of P2X7 in macrophages attenuated the quercetin‐mediated effects on M1 polarization, migration, and inflammation. Either P2X7 or NLRP3 knockdown attenuated IL‐1β‐induced M1/M2 polarization, migration, and inflammation. Moreover, overexpression of TRPV1 reduced the quercetin‐mediated suppressive effects on OA by promoting M1/M2‐polarized macrophages in vivo. Collectively, our data showed that quercetin‐induced suppression of TRPV1 leads to a delay in OA progression by shifting the macrophage polarization from M1 to M2 subtypes via modulation of the P2X7/NLRP3 pathway. [ABSTRACT FROM AUTHOR]

Tumour necrosis factor‐α (TNF‐α) is a cytokine involved in systemic inflammation. TNF‐α slows down osteogenic differentiation, which may contribute to poor bone development in the inflammatory microenvironment. TNF‐α inhibits osteogenic differentiation by activating the JAK‐STAT3 pathway, of which Signal transducer and activator of transcription 3 (STAT3)‐interacting protein 1 (StIP1, also known as elongator complex protein 2, ELP2) is a key protein in the JAK‐STAT3 pathway. We investigated whether and how ELP2 activation mediates the TNF‐α‐induced pyroptosis during osteoblastic differentiation. Using in vitro cell cultures of preosteoblastic MC3T3‐E1 cells, we found that TNF‐α exposure causes cell pyroptosis in an inflammatory microenvironment during osteoblastic differentiation. Bioinformatics, protein docking model and co‐immunoprecipitation analysis revealed an association between ELP2, STAT3 and NLRP3. Forced ELP2 expression promoted MC3T3‐E1 cells pyroptosis, with an increase in the expression of STAT3, NLRP3 inflammasome, GSDMD/GSDME, osteoblast marker genes, and the activity of alkaline phosphatase. In contrast, ELP2 silencing ameliorated MC3T3‐E1 cells pyroptosis, and osteogenic differentiation, especially after TNF‐α stimulation. The TNF‐α‐induced cells pyroptosis during osteoblastic differentiation was therefore mediated by ELP2. These results suggest that ELP2 is upregulated at the pyroptosis of MC3T3‐E1 cells and inhibits osteogenic differentiation in response to TNF‐α through NLRP3‐GSDMD/GSDME activation. [ABSTRACT FROM AUTHOR]

The purpose of this case–control study was to examine possible links between NLRP3 gene polymorphisms and the risk of developing posttraumatic osteomyelitis (PTOM) in the Chinese population. A total of 306 patients with PTOM and 368 normal controls were genotyped for NLRP3 (rs35829419, rs10754558, rs7525979, rs4612666), ELP2 (rs1785929, rs1789547, rs1785928, rs12185396, rs681757, rs8299, rs2032206, rs559289), STAT3 (rs4796793, rs744166, rs1026916, rs2293152, rs1053004), CASP1 (rs501192, rs580253, rs556205, rs530537), NFKBIA (rs696), NFKB1 (rs4648068), CARD8 (rs204321), and CD14 (rs2569190) using the genotyping technique SNaPshot. The genotype distributions of NLRP3 gene rs10754558 (p = 0.047) and rs7525979 (p = 0.048) significantly differed between the patients and the healthy controls. Additionally, heterozygous models indicated a significant association between NLRP3 rs10754558 and the likelihood of developing PTOM (OR = 1.600, p = 0.039), as did recessive and homozygous models of NLRP3 rs7525979 (OR = 0.248, p = 0.019 and 0.239, p = 0.016, respectively). Collectively, our findings suggest that, in the Chinese population, the risk of developing PTOM was increased by the association between NLRP3 rs10754558 and rs7525979. Therefore, our findings may provide novel insights and guidance in the prevention and development of PTOM. [ABSTRACT FROM AUTHOR]

The objective of the study was to identify extracellular vesicle (EV) microRNAs (miRNAs) that play important roles in knee osteoarthritis (OA). Models of knee OA were surgically induced in nine male Sprague-Dawley rats. Tissue samples were collected at 0 weeks (Control), 6 weeks (6 weeks), and 12 weeks (12 weeks). The EVs were isolated and analyzed for size. Various biomarkers, including recombinant tetraspanin 30 cluster of differentiation (CD)63 and CD9 were detected. An Agilent array was used to screen for differentially expressed (DE) miRNAs. The levels of DE miRNAs and their target mRNAs were evaluated by quantitative reverse transcription–polymerase chain reaction and western blotting. The viability, proliferation, and apoptosis of lipopolysaccharide (LPS)-induced human synovial cells (HSCs) were examined by using Cell Counting Kit-8, EdU (5-ethynyl-2′-deoxyuridine), and TUNEL (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling) assays, respectively. The OA model rats had significantly increased levels of inflammatory activity, damaged cells, and rough articular cartilage when compared with rats in the control group. The EVs from the model rats appeared as round vesicle-like structures with a mean diameter of ∼145 nm. Five miRNAs that showed gradual increases in the model rats were selected for further analysis; those miRNAs included miR-127-3p, miR-132-3p, miR-141-3p, miR-345-5p, and miR-382-5p. miR-382-5p was found to reduce the viability and proliferation and promote the apoptosis of LPS-induced HSCs. Moreover, phosphatase and tensin homolog deleted on chromosome 10 (PTEN) was negatively regulated by miR-382-5p. Our findings revealed that EVs produced by the OA rats contained miR-382-5p, which might reduce cell viability and proliferation, and promote cell apoptosis by targeting PTEN. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effect of transverse tibial bone transport on the treatment of Wagner Stage 4 diabetic foot. Methods: From January 2017 to October 2019, a total of 19 patients with Wagner Stage 4 diabetic foot ulcers were recruited. All patients were treated with transverse tibial bone transport. A detailed follow‐up was carried out at 1 week, 1 month, 3 months, 6 months, and 1 year after surgery. The wound healing rate and the limb salvage rate at 1 year after the surgery were evaluated. Preoperative and 3‐month postoperative digital subtraction angiography (DSA) were obtained. The level of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), epidermal growth factor (EGF) and platelet‐derived growth factor (PDGF) before surgery and on 1st, 4th, 11th, 18th, 28th, and 35th days after surgery were measured. Operation time, intraoperative blood loss, postoperative complications, visual analog scale (VAS) pain score, skin temperature, Semmes‐weinstein monofilament (SWM), and ankle brachial index (ABI) were also assessed. Results: The wound healing rate and the limb salvage rate were both 94.74% in the patients at 1 year after the surgery. DSA showed the thickening of the calf and foot arteries, clear visualization, and a rich vascular network. The levels of VEGF, bFGF, and PDGF on the 11th, 18th, 28th, and 35th days after surgery were significantly higher than those before surgery (p < 0.05). The EGF level on the 18th, 28th, and 35th days after surgery was significantly higher than that before surgery (p < 0.05). Superficial wound complications occurred in one patient during the hospitalization. There was no movement area infection, skin flap necrosis, tibial fracture, loosening of the external fixator, or rupture in study. Conclusion: Transverse tibial bone transport can improve the blood circulation of the affected limbs, promote the healing of diabetic foot wounds, and reduce the amputation rate of the affected limbs. Transverse tibial bone transport can promote the healing of Wagner Stage 4 diabetic foot. [ABSTRACT FROM AUTHOR]