Impact of battery electric vehicle usage on air quality in three Chinese first-tier cities.

China, the world leader in automobile production and sales, confronts the challenge of transportation emissions, which account for roughly 10% of its total carbon emissions. This study, utilizing real-world vehicle data from three major Chinese cities, assesses the impact of Battery Electric Vehicles (BEVs) on air quality. Our analysis reveals that BEVs, when replacing gasoline vehicles in their operational phase, significantly reduce emissions, with reductions ranging from 8.72 to 85.71 kg of CO2 per vehicle monthly. The average monthly reduction rate is 9.47%, though this effect is less pronounced during winter. Advanced BEVs, characterized by higher efficiency and newer technology, exhibit greater emission reduction benefits. While private BEVs generally contribute positively to environmental outcomes, taxi BEVs, due to their intensive usage patterns, show less environmental advantage and may sometimes worsen air quality. Looking ahead, we project substantial emission reductions from the replacement of gasoline vehicles with electric alternatives over the next decade. Policymakers are urged to adopt proactive measures, focusing on promoting medium to large electric vehicles and fostering the use of private and ride-hailing electric vehicles.

IDG-SW3 Cell Culture in a Three-Dimensional Extracellular Matrix.

Osteocytes are considered to be nonproliferative cells that are terminally differentiated from osteoblasts. Osteoblasts embedded in the bone extracellular matrix (osteoid) express the Pdpn gene to form cellular dendrites and transform into preosteocytes. Later, preosteocytes express the Dmp1 gene to promote matrix mineralization and thereby transform into mature osteocytes.This process is called osteocytogenesis. IDG-SW3 is a well-known cell line for in vitro studies of osteocytogenesis. Many previous methods have used collagen I as the main or the only component of the culturing matrix. However, in addition to collagen I, the osteoid also contains a ground substance, which is an important component in promoting cellular growth, adhesion, and migration. In addition, the matrix substance is transparent, which increases the transparency of the collagen I-formed gel and, thus, aids the exploration of dendrite formation through imaging techniques. Thus, this paper details a protocol to establish a 3D gel using an extracellular matrix along with collagen I for IDG-SW3 survival. In this work, dendrite formation and gene expression were analyzed during osteocytogenesis. After 7 days of osteogenic culture, an extensive dendrite network was clearly observed under a fluorescence confocal microscope. Real-time PCR showed that the mRNA levels of Pdpn and Dmp1 continually increased for 3 weeks. At week 4, the stereomicroscope revealed an opaque gel filled with mineral particles, consistent with the X-ray fluorescence (XRF) assay. These results indicate that this culture matrix successfully facilitates the transition from osteoblasts to mature osteocytes.

Urchin-like ceria nanoparticles for enhanced gene therapy of osteoarthritis.

Osteoarthritis (OA) is the most common degenerative joint disease in the world. Gene therapy based on delivering microRNAs (miRNAs) into cells has potential for the treatment of OA. However, the effects of miRNAs are limited by the poor cellular uptake and stability. Here, we first identify a type of microRNA-224-5p (miR-224-5p) from clinical samples of patients with OA that can protect articular cartilage from degeneration and further synthesize urchin-like ceria nanoparticles (NPs) that can load miR-224-5p for enhanced gene therapy of OA. Compared with traditional sphere ceria NPs, the thorns of urchin-like ceria NPs can efficiently promote the transfection of miR-224-5p. In addition, urchin-like ceria NPs have excellent performance of scavenging reactive oxygen species (ROS), which can regulate the microenvironment of OA to further improve the gene treatment of OA. The combination of urchin-like ceria NPs and miR-224-5p not only exhibits favorable curative effect for OA but also provides a promising paradigm for translational medicine.

Vascularized polypeptide hydrogel modulates macrophage polarization for wound healing.

Wound repair involves a sophisticated process that includes angiogenesis, immunoregulation and collagen deposition. However, weak revascularization performance and the lack of biochemical cues to trigger immunomodulatory function currently limit biomaterial applications for skin regeneration and tissue engineering. Herein, we fabricate a new bioactive polypeptide hydrogel (QK-SF) constituted by silk fibroin (SF) and a vascular endothelial growth factor mimetic peptide KLTWQELYQLKYKGI (QK) for tissue regeneration by simultaneously promoting vascularization and macrophage polarization. Our results showed that this QK-SF hydrogel can be prepared via an easy manufacturing process, and exhibited good gel stability and low cytotoxicity to cultured human umbilical vein endothelial cells (HUVECs) via both live/dead and cell counting kit-8 assays. Importantly, this QK-SF hydrogel triggered macrophage polarization from M1 into M2, as exemplified by the enhanced expression of the M2 marker and decreased expression of the M1 marker in RAW264.7 cells. Furthermore, the QK-SF hydrogel showed high capacity for inducing endothelial growth, migration and angiogenesis, which were proved by increased expression of angiogenesis-related genes in HUVECs. Consistent with in vitro findings, in vivo data show that the QK-SF hydrogel promoted M2 polarization, keratinocyte differentiation, and collagen deposition in the mouse skin wound model in immunohistochemistry assay. Furthermore, this QK-SF hydrogel can reduce inflammation, induce angiogenesis and promote wound healing as exemplified by the increased vessel formation and decreased wound area in the mouse skin wound model. Altogether, these results indicate that the bioactive QK-SF hydrogel plays dual functional roles in promoting angiogenesis and immunoregulation for tissue regeneration. STATEMENT OF SIGNIFICANCE: The QK-SF hydrogel plays dual functional roles in promoting angiogenesis and immunoregulation for tissue repair and wound healing. The QK-SF hydrogel can be prepared via an easy manufacturing process, and exhibited good gel stability and low cytotoxicity to cultured HUVECs. The QK-SF hydrogel triggered macrophage polarization from M1 into M2. The QK-SF hydrogel showed high capacity for inducing endothelial growth, migration and angiogenesis. The QK-SF hydrogel promoted M2 polarization, keratinocyte differentiation, and collagen deposition.

DNA-Grafted Hyaluronic Acid System with Enhanced Injectability and Biostability for Photo-Controlled Osteoarthritis Gene Therapy.

Gene therapy is identified as a powerful strategy to overcome the limitations of traditional therapeutics to achieve satisfactory effects. However, various challenges related to the dosage form, delivery method, and, especially, application value, hampered the clinical transition of gene therapy. Here, aiming to regulate the cartilage inflammation and degeneration related abnormal IL-1ß mRNA expression in osteoarthritis (OA), the interference oligonucleotides is integrated with the Au nanorods to fabricate the spherical nucleic acids (SNAs), to promote the stability and cell internalization efficiency. Furthermore, the complementary oligonucleotides are grafted onto hyaluronic acid (HA) to obtained DNA-grafted HA (DNAHA) for SNAs delivery by base pairing, resulting in significantly improved injectability and bio-stability of the system. After loading SNAs, the constructed DNAHA-SNAs system (HA-SNAs) performs a reversible NIR-triggered on-demand release of SNAs by photo-thermal induced DNA dehybridization and followed by post-NIR in situ hybridization. The in vitro and in vivo experiments showed that this system down-regulated catabolic proteases and up-regulated anabolic components in cartilage over extended periods of time, to safeguard the chondrocytes against degenerative changes and impede the continual advancement of OA.

Baicalein alleviates osteoarthritis by protecting subchondral bone, inhibiting angiogenesis and synovial proliferation.

Osteoarthritis (OA) is one of the most frequent chronic joint diseases with the increasing life expectancy. The main characteristics of the disease are loss of articular cartilage, subchondral bone sclerosis and synovium inflammation. Physical measures, drug therapy and surgery are the mainstay of treatments for OA, whereas drug therapies are mainly limited to analgesics, glucocorticoids, hyaluronic acids and some alternative therapies because of single therapeutic target of OA joints. Baicalein, a traditional Chinese medicine extracted from Scutellaria baicalensis Georgi, has been widely used in anti-inflammatory therapies. Previous studies revealed that baicalein could alleviate cartilage degeneration effectively by acting on articular chondrocytes. However, the mechanisms involved in baicalein-mediated protection of the OA are not completely understood in consideration of integrality of arthrosis. In this study, we found that intra-articular injection of baicalein ameliorated subchondral bone remodelling. Further studies showed that baicalein could decrease the number of differentiated osteoblasts by inhibiting pre-osteoblasts proliferation and promoting pre-osteoblasts apoptosis. In addition, baicalein impaired angiogenesis of endothelial cells and inhibited proliferation of synovial cells. Taken together, these results implicated that baicalein might be an effective medicine for treating OA by regulating multiple targets.

Osteopontin activates retinal microglia causing retinal ganglion cells loss via p38 MAPK signaling pathway in glaucoma.

Microglia activation and release of pro-inflammatory cytokines have been closely linked to glaucoma. However, the mechanisms that initiate these pathways remain unclear. Here, we investigated the role of a pro-inflammatory cytokine--osteopontin (OPN), in retinal microglia activation process along with the underlying mechanisms in glaucoma. A rat chronic ocular hypertension (COH) model was established presenting an increase in retinal OPN level and activation of microglia. Primary microglia cells were isolated and cultured under a pressure culture system showing heightened expressions of microglia-derived OPN with changes in inflammatory factors (TNF-α, IL-1ß, and IL-6). OPN and OPN neutralizing antibody (Anti-OPN) interventions were both applied systems for comparison, and cross-referenced with OPN knockdown in vitro. JAK/STAT, NF-κB, ERK1/2, and p38 MAPK, recognized as the primary signaling pathways related to microglia activation, were then screened on whether they can facilitate OPN to act on microglia and their impact on specific inhibitors. Thereafter, retrograde labeling of retinal ganglion cells (RGCs) and flash visual evoked potentials (F-VEP) were used to investigate neuron protection in context of each blockade. Results suggest that OPN is able to enhance the proliferation and activation of retinal microglia in experimental glaucoma which may play a role in the glaucomatous optic neuropathy, and contribute to the eventual RGCs loss and vision function impairment. Such effect may be mediated through the regulation of p38 MAPK signaling pathway.

Malalignment and distal contact of short tapered stems could be associated with postoperative thigh pain in primary total hip arthroplasty.

PURPOSE: Short tapered stem placement has been extensively employed in total hip arthroplasty (THA). Suboptimal fixation tends to cause postoperative complications, such as thigh pain. However, it remains unclear whether poor seating/alignment of short tapered stems contributes to thigh pain. In this study, we retrospectively examined the factors that might be associated with thigh pain. METHODS: Medical records of 230 patients who had undergone THAs at our hospital were reviewed retrospectively. All patients received the same mediolateral (ML) short tapered femoral stems. The association between thigh pain and patients' demographics, radiographic findings, or the type of fitting of the femoral stems was investigated. RESULTS: In our cohort, 68 patients (27.8%) presented with thigh pain. Among 203 type I fit patients, 62 (30.5%) developed thigh pain, while only 6 out of 43 (12.2%) type II fit patients had thigh pain, with the differences being statistically significant (x2 = 6.706, p = 0.01). In addition, hip anteroposterior radiographs exhibited that the stem angulation (mean 2.52°), the variation in angulation (mean 1.32°), and the extent of femoral stem subsidence (mean 0.29 cm) were greater in patients with thigh pain than in their counterparts without thigh pain (all p < 0.05). CONCLUSION: Malalignment and improper seating of short tapered stems could be at least one of the reasons for post-THA thigh pain. The distal contact between the stem tip and the medial femoral cortex might result in thigh pain. Our study suggested that distal implant contact should be avoided, and stem alignment should be meticulously performed in the placement of ML short tapered femoral stems for THA.

Effects of posterior tibial slope on the mid-term results of medial unicompartmental knee arthroplasty.

OBJECTIVE: To evaluate the effect of medial posterior tibial slope (PTS) on mid-term postoperative range of motion (ROM) and functional improvement of the knee after medial unicompartmental knee arthroplasty (UKA). METHODS: Medical records of 113 patients who had undergone 124 medial UKAs between April 2009 through April 2014 were reviewed retrospectively. The mean follow-up lasted 7.6 years (range, 6.2-11.2 years). Collected were demographic data, including gender, age, height, weight of the patients. Anteroposterior (AP) and lateral knee radiographs of the operated knees were available in all patients. The knee function was evaluated during office follow-up or hospital stay. Meanwhile, postoperative PTS, ROM, maximal knee flexion and Hospital for Special Surgery (HSS) knee score (pre-/postoperative) of the operated side were measured and assessed. According to the size of the PTS, patients were divided into 3 groups: group 1 (<4°), group 2 (4° ~ 7°) and group 3 (>7°). The association between PTS and the knee function was investigated. RESULTS: In our cohort, the average PTS was 2.7° ± 0.6° in group 1, 5.6° ± 0.9° in group 2 and 8.7° ± 1.2° in group 3. Pairwise comparisons showed significant differences among them (p < 0.01). The average maximal flexion range of postoperative knees in each group was 112.4° ± 5.6°, 116.4° ± 7.2°, and 117.5° ± 6.1°, respectively, with significant difference found between group 1 and group 2 (p < 0.05), and between group 1 and group 3 (p < 0.05). However, the gender, age, and body mass index (BMI) did not differ between three groups and there was no significant difference between groups in terms of pre-/postoperative HSS scores or postoperative knee ROM. CONCLUSION: A mid-term follow-up showed that an appropriate PTS (4° ~ 7°) can help improve the postoperative flexion of knee. On the other hand, too small a PTS could lead to limited postoperative knee flexion. Therefore, the PTS less than 4° should be avoided during medial UKA.

Osteocytic HIF-1α Pathway Manipulates Bone Micro-structure and Remodeling via Regulating Osteocyte Terminal Differentiation.

The activation of hypoxia-inducible factor 1α (HIF-1α) signaling has promising implications for the treatment of bone diseases such as osteoporosis and skeletal fractures. However, the effects of manipulating HIF-1α pathway on bone micro-structure and remodeling should be fully studied before the clinical application of therapeutics that interfere with the HIF-1α pathway. In this study, we found that osteocyte-specific HIF-1α pathway had critical role in manipulating bone mass accrual, bone material properties and micro-structures, including bone mineralization, bone collagen fiber formation, osteocyte/canalicular network, and bone remodeling. In addition, our results suggest that osteocyte-specific HIF-1α pathway regulates bone micro-structure and remodeling via impairing osteocyte differentiation and maturation.

High Mineralization Capacity of IDG-SW3 Cells in 3D Collagen Hydrogel for Bone Healing in Estrogen-Deficient Mice.

Tissue engineering with 3D scaffold is a simple and effective method for bone healing after large-scale bone loss. So far, bone marrow-derived mesenchymal stem cells (BMSCs) are mostly used in the treatment of bone healing in animal models due to their self-renewal capability and osteogenic potential. Due to the fact that the main functional cells in promoting osteoid mineralization and bone remodeling were osteocytes, we chose an osteoblast-to-osteocyte transition cell line, IDG-SW3, which are not proliferative under physiological conditions, and compared the healing capability of these cells to that of BMSCs in bone defect. In vitro, IDG-SW3 cells revealed a stronger mineralization capacity when grown in 3D collagen gel, compared to that of BMSCs. Although both BMSC and IDG-SW3 can generate stable calcium-phosphate crystal similar to hydroxyapatite (HA), the content was much more enriched in IDG-SW3-mixed collagen gel. Moreover, the osteoclasts co-cultured with IDG-SW3-mixed collagen gel were easier to be activated, indicating that the IDG-SW3 grafting could promote the bone remodeling more efficiently in vivo. Last, in order to reduce the self-healing capability, we assessed the healing capability between the IDG-SW3 cells and BMSCs in osteoporotic mice. We found that the collagen hydrogel mixed with IDG-SW3 cells has a better healing pattern than what was seen in hydrogel mixed with BMSCs. Therefore, these results demonstrated that by promoting osteoblast-to-osteocyte transition, the therapeutic effect of BMSCs in bone defect repair could be improved.

Up-regulated microRNA-411 or declined RIPK1 inhibits proliferation and promotes apoptosis of synoviocytes in rheumatoid arthritis mice via decreased NF-κB pathway.

Rheumatoid arthritis (RA) is a chronic and inflammatory synovitis systemic disease. Due to the unknown pathogenesis, this study was to investigate the effect of microRNA (miR)-411 on apoptosis and joint function of synoviocytes in RA mice via RIPK1-mediated NF-κB signaling pathway. The collagen-induced arthritis model mice were induced via collagen type II and Freund's adjuvant. The mice were injected with miR-411 mimics, si-RIPK1 or miR-411 mimics + oe-RIPK1 to figure out their roles in cell apoptosis and inflammation of synovial tissues. Synoviocytes were grouped as in animal experiments. Proliferation and apoptosis of synoviocytes were detected upon treatment with overexpressed miR-411 and silenced RIPK1. The expression of miR-411, RIPK1 and NF-κB in synovial tissues and synoviocytes of RA mice was detected by RT-qPCR and Western blot analysis. Poorly expressed miR-411, and highly expressed NF-κB and RIPK1 existed in synovial tissue and synoviocytes of RA. Additionally, it was found that si-RIPK1 decreased NF-κB expression, and miR-411 mimics decreased both RIPK1 and NF-κB. MiR-411 had a targeted relationship with RIPK1. si-RIPK1 or miR-411 mimics promoted cell apoptosis and strained inflammation in synovial tissues of mice with RA. Overexpressed miR-411 or silencing RIPK1 inhibited the proliferation and promoted apoptosis of synoviocytes of RA mice. Up-regulation of miR-411 or down-regulation of RIPK1 had a certain inhibitory effect on RA. This study suggests that up-regulated miR-411 or down-regulated RIPK1 promoted apoptosis and inhibited proliferation of synoviocytes of RA mice, which may be related to the inhibition of NF-κB activation.

Differential Expression Profiles and Functional Predication of Circular Ribonucleic Acid in Traumatic Spinal Cord Injury of Rats.

Recent studies indicate that circular ribonucleic acids (circRNAs) are involved in a variety of human diseases. The roles of circRNAs in traumatic spinal cord injury (SCI) remain unknown, however. We performed RNA-seq to analyze the circRNA expression profile in rat spinal cord after SCI and to investigate the relevant mechanisms. In all, 150 circRNAs were significantly differentially expressed in rat spinal cord after SCI by a fold-change ≥2 and p value ≤0.05. Among these, 99 circRNAs were upregulated, while 51 were downregulated. Gene ontology, Kyoto Encyclopedia of Genes and Genomes pathway analyses, and circRNA/miocroRNA (miRNA) interaction networks were conducted to predict the potential roles of circRNAs in the process of SCI. In addition, the expression levels of six selected circRNAs were verified successfully by quantitative real-time polymerase chain reaction. Further study identified circRNA_07079 and circRNA_01282 as being associated with SCI, and they may participate in the pathophysiology of SCI through circRNA-targeted miRNA-messenger RNA axis. In summary, the results of our study revealed the expression profiles and potential functions of differentially expressed circRNAs in traumatic SCI in rats; this may provide new clues for studying the mechanisms underlying SCI and also present novel molecular targets for clinical therapy of SCI.

TRAF6 neddylation drives inflammatory arthritis by increasing NF-κB activation.

Neddylation is a process similar to ubiquitination, and is critical in various inflammatory diseases; however, its importance in the pathogenesis of inflammatory arthritis is not well understood. Here, we investigated the role of neddylation in collagen-induced arthritis (CIA) and its clinical relevance. We showed that neddylation-related genes, including NEDD8 and CULLIN-1, were significantly upregulated in inflamed arthritic synovia. Functionally, neddylation activation was crucial for synovitis of CIA, as the inhibition of neddylation by MLN4924 significantly suppressed synovial cell proliferation and inflammatory responses. Mechanistically, neddylation mediated inflammatory arthritis by regulating NF-κB activation in fibroblast-like synovial cells (FLSs). Furthermore, TNF receptor-associated factor 6 (TRAF6) neddylation at Lys124 was essential for IL-17A-induced NF-κB activation. Replacing the Lys-124 residue with Arg (K124R) resulted in significantly impaired conjugation of NEDD8 to TRAF6, as well as markedly attenuated IL-17A-induced NF-κB activity. Therefore, the pathogenic role of neddylation in CIA as well as its mechanism of action demonstrated here provides a new insight into understanding the role of post-transcriptional modifications in the arthritis inflammatory response.

Enhanced Osteogenesis of Bone Marrow-Derived Mesenchymal Stem Cells by a Functionalized Silk Fibroin Hydrogel for Bone Defect Repair.

Silk fibroin (SF) from Bombyx mori is a promising natural material for the synthesis of biocompatible and biodegradable hydrogels for use in biomedical applications from tissue engineering to drug delivery. However, weak gelation performance and the lack of biochemical cues to trigger cell proliferation and differentiation currently significantly limit its application in these areas. Herein, a biofunctional hydrogel containing SF (2.0%) and a small peptide gelator (e.g., NapFFRGD = 1.0 wt%) is generated via cooperative molecular self-assembly. The introduction of NapFFRGD to SF is shown to significantly improve its gelation properties by lowering both its threshold gelation concentration to 2.0% and gelation time to 20 min under physiological conditions (pH = 7.4, 37 °C), as well as functionalizing the SF hydrogel with cell-adhesive motifs (e.g., RGD). Besides mediating cell adhesion, the RGD ligands incorporated within the SF-RGD gel promote the osteogenic differentiation of bone marrow-derived mesenchymal stem cells encapsulated within the gel matrix, leading to bone regeneration in a mouse calvarial defect model, compared with a blank SF gel (2.0%, pH = 7.4). This work suggests that SF could be easily tailored with bioactive peptide gelators to afford bioactive hydrogels with favorable microenvironments for tissue regeneration applications.

Vascularized 3D printed scaffolds for promoting bone regeneration.

3D printed scaffolds hold promising perspective for bone tissue regeneration. Inspired by process of bone development stage, 3D printed scaffolds with rapid internal vascularization ability and robust osteoinduction bioactivity will be an ideal bone substitute for clinical use. Here, we fabricated a 3D printed biodegradable scaffold that can control release deferoxamine, via surface aminolysis and layer-by-layer assembly technique, which is essential for angiogenesis and osteogenesis and match to bone development and reconstruction. Our in vitro studies show that the scaffold significantly accelerates the vascular pattern formation of human umbilical endothelial cells, boosts the mineralized matrix production, and the expression of osteogenesis-related genes during osteogenic differentiation of mesenchymal stem cells. In vivo results show that deferoxamine promotes the vascular ingrowth and enhances the bone regeneration at the defect site in a rat large bone defect model. Moreover, this 3D-printed scaffold has excellent biocompatibility that is suitable for mesenchymal stem cells grow and differentiate and possess the appropriate mechanical property that is similar to natural cancellous bone. In summary, this 3D-printed scaffold holds huge potential for clinical translation in the treatment of segmental bone defect, due to its flexibility, economical friendly and practicality.

Estrogen inhibits osteoclasts formation and bone resorption via microRNA-27a targeting PPARγ and APC.

Inhibition of osteoclasts formation and bone resorption by estrogen is very important in the etiology of postmenopausal osteoporosis. The mechanisms of this process are still not fully understood. Recent studies implicated an important role of microRNAs in estrogen-mediated responses in various cellular processes, including cell differentiation and proliferation. Thus, we hypothesized that these regulatory molecules might be implicated in the process of estrogen-decreased osteoclasts formation and bone resorption. Western blot, quantitative real-time polymerase chain reaction, tartrate-resistant acid phosphatase staining, pit formation assay and luciferase assay were used to investigate the role of microRNAs in estrogen-inhibited osteoclast differentiation and bone resorption. We found that estrogen could directly suppress receptor activator of nuclear factor B ligand/macrophage colony-stimulating factor-induced differentiation of bone marrow-derived macrophages into osteoclasts in the absence of stromal cell. MicroRNA-27a was significantly increased during the process of estrogen-decreased osteoclast differentiation. Overexpressing of microRNA-27a remarkably enhanced the inhibitory effect of estrogen on osteoclast differentiation and bone resorption, whereas which were alleviated by microRNA-27a depletion. Mechanistic studies showed that microRNA-27a inhibited peroxisome proliferator-activated receptor gamma (PPARγ) and adenomatous polyposis coli (APC) expression in osteoclasts through a microRNA-27a binding site within the 3'-untranslational region of PPARγ and APC. PPARγ and APC respectively contributed to microRNA-27a-decreased osteoclast differentiation and bone resorption. Taken together, these results showed that microRNA-27a may play a significant role in the process of estrogen-inhibited osteoclast differentiation and function.

Double-stranded RNA released from damaged articular chondrocytes promotes cartilage degeneration via Toll-like receptor 3-interleukin-33 pathway.

Pattern recognition receptors (PRRs), including Toll-like receptor 3 (TLR3), are involved in arthritic responses; however, whether interleukin-33 (IL-33) is involved in TLR3-mediated cartilage degeneration is unknown. Here, we found that IL-33 was abundantly increased in chondrocytes of osteoarthritis, especially the chondrocytes of weight-bearing cartilage. Furthermore, double-stranded RNA (dsRNA) released from damaged articular chondrocytes induced by mechanical stretching upregulated IL-33 expression to a greater degree than IL-1ß and tumor necrosis factor-α. dsRNA induced IL-33 expression via the TLR3-p38 mitogen-activated protein kinase-nuclear factor-κB (NF-κB) pathway. In addition, formation of the p65 and peroxisome proliferator-activated receptor-γ transcriptional complex was required for dsRNA-induced IL-33 expression. IL-33, in turn, acted on chondrocytes to induce matrix metalloproteinase-1/13 and inhibit type II collagen expression. These findings reveal that dsRNA released from damaged articular chondrocytes promotes cartilage degeneration via the TLR3-IL-33 pathway.

Increased 15-lipoxygenase-1 expression in chondrocytes contributes to the pathogenesis of osteoarthritis.

15-Lipoxygenase-1 (15-LO-1) is involved in many pathological processes. The purpose of this study was to determine the potential role of 15-LO-1 in osteoarthritis (OA). The levels of 15-LO-1 expression were measured by western blotting and quantitative real-time PCR in articular cartilage from the OA rat models and OA patients. To further investigate the effects of 15-LO-1 on chondrocyte functions, such as extracellular matrix (ECM) secretion, the release of matrix-degrading enzymes, the production of reactive oxygen species (ROS), cell proliferation and apoptosis, we decreased or increased 15-LO-1 expression in chondrocytes by means of transfecting with siRNA targeting 15-LO-1 and plasmid encoding 15-LO-1, respectively. The results showed that 15-LO-1 expression was obviously increased in articular cartilage from OA rats and OA patients. It was also found that many factor-related OA, such as mechanical loading, ROS, SNP and inflammatory factor, significantly promoted 15-LO-1 expression and activity in chondrocytes. Silencing 15-LO-1 was able to markedly alleviate mechanical loading-induced cartilage ECM secretion, cartilage-degrading enzyme secretion and ROS production. Overexpression of 15-LO-1 could inhibit chondrocyte proliferation and induce chondrocyte apoptosis. In addition, reduction of 15-LO-1 in vivo significantly alleviated OA. Taken together, these results indicate that 15-LO-1 has an important role in the disease progression of OA. Thus 15-LO-1 may be a good target for developing drugs in the treatment of OA.

Poor performance of Enduron polyethylene liner in total hip arthroplasty: a minimum ten-year follow up and ultra-morphological analysis of wear particles.

PURPOSE: The aim of the present study was to investigate the long-term outcome and the wear characteristics of two distinct types of ultra-high molecular weight polyethylene (UHMWPE) liners in total hip arthroplasty (THA). METHODS: We conducted a retrospective clinical study on patients which were treated with total hip arthroplasty using either Enduron polyethylene (Enduron PE) or Trilogy polyethylene (Trilogy PE) liners based on a minimum of ten year follow up data. Morphological analyses of wear particles from tissue samples, which were harvested during revision surgeries, were also performed. RESULTS: A total of 79 THAs in the Enduron group and 55 THAs in the Trilogy group were available for analysis. Kaplan-Meier survival with revision for wear-related complications as the endpoint of the Enduron PE liners was lower than that of Trilogy PE liners at ten years (93.5 % and 100 %, P = 0.03). The Enduron group had higher mean linear wear rate than that of the Trilogy group (0.20 ± 0.09 and 0.09 ± 0.03 mm/year, P < 0.01). The incidence of osteolysis for the Enduron group was higher than that of the Trilogy group (33.3 % and 12 %, P = 0.04). Under transmission electron microscopy, the Enduron group had more than 82 % of the particles less than 1.0 µm in size and more than 57 % of the particles less than 0.5 µm. CONCLUSION: The long-term performance of Enduron liners was worse than that of Trilogy liners. Further clinical follow-up may be necessary in patients with Enduron PE liners in order to avoid catastrophic complications.