Comparison of the clinical efficacy of different fixation systems for the treatment of transverse patellar fractures.

PURPOSE: This study was designed to compare the clinical efficacy of "8" and "0" wire fixation systems combined with double-head cannulated compression screws or Kirschner wires for the treatment of transverse patellar fractures. METHODS: From September 2011 to September 2018, patients with closed transverse patellar fractures treated with a double-head compression screw or Kirschner wire were included and analyzed retrospectively. Patients with patellar fractures combined with distal femoral fractures, tibial plateau fracture or preoperative lower limb dysfunction were excluded. The patients treated with the "8" tension band wire fixation system and Kirschner wire were taken as Group A; those treated with the "0" fixation system and Kirschner wire were taken as Group B; those treated with the "8" fixation system and double-head cannulated compression screw were taken as group C; and those treated with the "0" fixation system and double-head cannulated compression screw were taken as group D. Six weeks and one year after the operation and every month from the third month after the operation until the fractures healed, an X-ray examination was performed to identify fracture healing. The time of fracture healing and postoperative complications of the four groups were compared. One year after the operation, knee function was evaluated by Bostman's score. RESULTS: During the study period, 168 patients with patellar fractures were treated by operations, and 88 patients were excluded because the fracture type did not meet the requirements or because there were combined fractures of the distal femur or tibial plateau. As a result, 80 patients were included in this study, 20 in each group. All the patients were followed up for an average period of 12.2 months. Compared with Group A, patients in Group D presented less postoperative discomfort in the prepatellar region, quicker fracture healing, less fixation failure and better postoperative knee function scores (all p < 0.05). The incidence of internal fixation failure in Group (B+D) was lower than that in Group (A+C) (p > 0.05). CONCLUSION: The "0" wire fixation system combined with a double-head cannulated compression screw seems to be more beneficial than the other three fixation systems for the treatment of transverse patellar fractures.

HO-1 overexpression alleviates senescence by inducing autophagy via the mitochondrial route in human nucleus pulposus cells.

Intervertebral disc degeneration (IDD) is closely associated with aging. Our previous studies have confirmed that heme oxygenase-1 (HO-1) can inhibit nucleus pulposus (NP) cell apoptosis. However, whether or not HO-1 is involved in NP cell senescence and autophagy is unclear. Our results indicated that HO-1 expression was reduced in IDD tissues and replicative senescent NP cells. HO-1 overexpression using a lentiviral vector reduced the NP cell senescence level, protected mitochondrial function, and promoted NP cell autophagy through the mitochondrial pathway. Autophagy inhibitor 3-MA pretreatment reversed the anti-senescent and protective effects on the mitochondrial function of HO-1, which promoted the degradation of the extracellular matrix (ECM) in the intervertebral disc. In vivo, HO-1 overexpression inhibited IDD and enhanced autophagy. In summary, these results suggested that HO-1 overexpression alleviates NP cell senescence by inducing autophagy via the mitochondrial route.

Propionibacterium acnes induces intervertebral disc degeneration by promoting nucleus pulposus cell pyroptosis via NLRP3-dependent pathway.

Recent evidence suggests that Propionibacterium acnes (P. acnes) is a novel pathogenic factor promoting intervertebral disc degeneration (IVDD), however, whose mechanism remains unclear. A key component of inflammatory responses to P. acnes appears to be interleukin (IL)-1ß, which has been proved to be high expression in degenerative nucleus pulposus cells (NPCs). This study aimed to explore the inflammatory mechanism driving the host response to P. acnes infection in IVDD. Our data demonstrated that the number of nod-like receptor protein 3 (NLRP3)-positive cells was significantly increased in the P. acnes-infected nucleus pulposus (NP) tissue. Meanwhile, the up-regulated expressions of NLRP3, caspase-1, caspase-5, IL-1ß, IL-18, Gasdermin D (GSDMD) were observed in NPCs after co-culturing with P. acnes, which suggested NPCs pyroptosis activation induced by P. acnes. To further investigate the underlying mechanisms, NLRP3 inflammasome inhibitor MCC950 and thioredoxin binding protein (TXNIP)-siRNA were used. With the addition of MCC950 to NPCs co-cultured with P. acnes in vitro, the secretions of mature IL-1ß and IL-18 were reduced. Moreover, these MCC950-mediated effects were repeated by siRNA-transfected TXNIP knockdown. These results implied P. acnes activated inflammatory response by the TXNIP-NLRP3 pathway. To further reveal the anti-degeneration role of MCC950 in vivo, MCC950 was injected into the rabbit IVDD models infected by P. acnes. The MRI and histological detection provided more solid evidence that MCC950 treatment effectively retarded the degenerative process of the intervertebral discs in vivo. In summary, these results suggest that P. acnes-induced NPCs pyroptosis activation via the NLRP3-dependent pathway is likely responsible for the inflammatory pathology of IVDD. MCC950 can alleviate inflammatory injury and NPCs pyroptosis under P. acnes infection and may delay the progression of disc degeneration, which provides a new direction for the treatment of IVDD.

PINK1 protects against oxidative stress induced senescence of human nucleus pulposus cells via regulating mitophagy.

Intervertebral disc degeneration (IDD) is closely related with aging, whereas mitochondrial dysfunction is a common feature of aging in which results cell senescence. Phosphatase and tensin homolog (PTEN)-induced putative kinase protein 1 (PINK1) is a mitochondrial-targeted serine/threonine kinase, which plays a protective role against mitochondrial dysfunction with mitochondrial quality control by activating PINK1/Parkin mediated mitophagy. This study aimed to investigate the protective role of PINK1 against mitochondrial dysfunction and human nucleus pulposus cell (NPC) senescence. We found that mitochondrial dysfunction and NPC senescence could be induced under sublethal oxidative stress by 150 µM H2O2. Moreover, down-regulation of PINK1 tended to aggravate NPC senescence under oxidative stress. Therefore, mitophagy was evaluated in NPCs to further reveal the underlying mechanism. Results showed that sublethal oxidative stress induced mitochondria dysfunction and mitophagy in NPCs. Furthermore, depletion of PINK1 utilizing short hairpin RNA targeting PINK1 (PINK1-shRNA) impaired mitophagy, and exasperated NPC senescence under oxidative stress. In summary, these results suggested that PINK1 played as a protective role in clearance of damaged mitochondrial and alleviating cell senescence under oxidative stress, whose mechanism is associated with regulating mitophagy. These findings may provide a better understanding in pathomechanism of IDD and potential therapeutic approaches for IDD treatment.

Anatomical evidence for the anterior plate fixation of sacroiliac joint.

BACKGROUND: The iatrogenic injuries to the lumbar nerves during the fixation the sacroiliac (SI) joint fractures with anterior plates were often reported. No specific method had been reported to avoid it. This study was done to find a safer way of placing the anterior plates and screws for treating the sacroiliac (SI) joint fracture and/or dislocation. METHODS: The research was performed using 8 male and 7 female normal corpse pelvic specimens preserved by 10% formalin solution. Try by measuring the horizontal distance from L4, L5 nerve roots to the sacroiliac joint and perpendicular distance from L4, L5 nerve roots to the ala sacralis, the length of L4, L5 nerve roots from intervertebral foramen to the edge of true pelvis, the diameter of L4, L5 nerve roots. The angles between the sacroiliac joint and sagittal plane were measured on the CT images. RESULTS: The horizontal distance between the lateral side of the anterior branches of L4, L5 nerve roots and the sacroiliac joint decreased gradually from the top to the bottom. The widest distances for L4,5 were 2.1 cm (range, 1.74-2.40) and 2.7 cm (range, 2.34-3.02 cm), respectively. The smallest distances for L4, 5 were 1.2 cm (range, 0.82-1.48 cm) and 1.5 cm (range, 1.08-1.74 cm), respectively. On CT images, the angle between the sacroiliac joint and sagittal plane was about 30°. CONCLUSIONS: If we use two anterior plates to fix the sacroiliac joint, It is recommended to place one plate on the superior one third part of the joint, with exposing medially no more than 2.5 cm and the other in the middle one third part of the joint, with elevating periosteum medially no more than 1.5 cm. The screws in the sacrum are advised to incline medially about 30° directing to the true pelvis.

Immobilizing c(RGDfc) on the surface of metal-phenolic networks by thiol-click reaction for accelerating osteointegration of implant.

The limited osteointegration often leads to the failure of implant, which can be improved by fixing bioactive molecules onto the surface, such as arginyl-glycyl-aspartic acid (RGD): a cell adhesion motif. Metal-Phenolic Networks (MPNs) have garnered increasing attention from different disciplines in recent years due to their simple and rapid process for depositing on various substrates or particles with different shapes. However, the lack of cellular binding sites on MPNs greatly blocks its application in tissue engineering. In this study, we present a facile and efficient approach for producing PC/Fe@c(RGDfc) composite coatings through the conjugation of c(RGDfc) peptides onto the surface of PC/Fe-MPNs utilizing thiol-click reaction. By combined various techniques (ellipsometry, X-ray photoelectron spectroscopy, Liquid Chromatography-Mass Spectrometry, water contact angle, scanning electronic microscopy, atomic force microscopy) the physicochemical properties (composition, coating mechanism and process, modulus and hydrophilicity) of PC/Fe@c(RGDfc) surface were characterized in detail. In addition, the PC/Fe@c(RGDfc) coating exhibits the remarkable ability to positively modulate cellular attachment, proliferation, migration and promoted bone-implant integration in vivo, maintaining the inherent features of MPNs: anti-inflammatory, anti-oxidative properties, as well as multiple substrate deposition. This work contributes to engineering MPNs-based coatings with bioactive molecules by a facile and efficient thiol-click reaction, as an innovative perspective for future development of surface modification of implant materials.

Machine learning-mediated identification of ferroptosis-related genes in osteonecrosis of the femoral head.

Osteonecrosis of the femoral head (ONFH) is a condition caused by a disruption or damage to the femoral head's blood supply, which causes the death of bone cells and bone marrow components and prevents future regeneration. Ferroptosis, a type of controlled cell death, is caused by iron-dependent lipid peroxidation. Here, we identified ferroptosis-related genes and infiltrating immune cells involved in ONFH and predicted the underlying molecular mechanisms. The GSE123568 dataset was subjected to differential expression analysis to identify genes related to ferroptosis. Subsequently, GO and KEGG pathway enrichment analyses, as well as protein-protein interaction (PPI) network analysis, were conducted. Hub genes involved in ferroptosis were identified using machine learning and other techniques. Additionally, immune infiltration analysis and lncRNA-miRNA-mRNA network prediction analysis were performed. Finally, we determined whether ferroptosis occurred by measuring iron content. The hub genes were validated by ROC curve analysis and qRT-PCR. Four ferroptosis-related hub genes (MAPK3, PTGS2, STK11, and SLC2A1) were identified. Additionally, immune infiltration analysis revealed a strong correlation among ONFH, hub genes, and various immune cells. Finally, we predicted the network relationship between differentially expressed lncRNAs and hub genes in the lncRNA-miRNA-mRNA network. MAPK3, PTGS2, STK11, and SLC2A1 have been identified as potential ferroptosis-related biomarkers and drug targets for the diagnosis and prognosis of ONFH, while some immune cells, as well as the interaction between lncRNA, miRNA, and mRNA, have also been identified as potential pathogenesis markers and therapeutic targets.

Engineering tunable dual peptide hybrid coatings promote osseointegration of implants.

Utilizing complementary bioactive peptides is a promising surface engineering strategy for bone regeneration on osteogenesis. In this study, we designed block peptides, (Lysine)6-capped RGD (K6-(linker-RGD)3) and OGP (K6-linker-(YGFGG)2), which were mildly grafted onto PC/Fe-MPNs through supramolecular interactions between K6 and PC residues on the MPNs surface to form a dual peptide coating, named PC/Fe@K6-RGD/OGP. The properties of the block peptides coating, including mechanics, hydrophilicity, chemical composition, etc., were detailly characterized by various techniques (ellipsometry, quartz crystal microbalance, X-ray photoelectron spectroscopy, water contact angle, scanning electronic microscopy and atomic force microscopy). Importantly, the RGD/OGP ratio can be well adjusted, which allowed optimizing the RGD/OGP ratio to endow significantly enhanced osteogenic activity of MC3T3-E1 cells through the Wnt/ß-catenin pathway, while also promoting cell adhesion, immune regulation, inhibiting osteoclast differentiation and oxidative stress reduction. In vivo, the optimized RGD/OGP coatings promoted bone regeneration and osseointegration around implants in rats with bone defects. In conclusion, rationally designed PC/Fe@K6-RGD/OGP coating integrated RGD and OGP bioactivities, providing a convenient approach to enhance bioinert implant surfaces for bone regeneration.

Melatonin protects human nucleus pulposus cells from pyroptosis by regulating Nrf2 via melatonin membrane receptors.

This study was performed to explore the effect of melatonin on pyroptosis in nucleus pulposus cells (NPCs) and the underlying mechanism of that effect. This experiment included three patients diagnosed with lumbar disc herniation who failed conservative treatment. Nucleus pulposus tissue was isolated from these patients when they underwent surgical intervention, and primary NPCs were isolated and cultured. Western blotting, reverse transcription polymerase chain reaction, fluorescence staining, and other methods were used to detect changes in related signalling pathways and the ability of cells to resist pyroptosis. Western blot analysis confirmed the expression of cleaved CASP-1 and melatonin receptor (MT-1A-R) in NPCs. The cultured NPCs were identified by detecting the expression of CD24, collagen type II, and aggrecan. After treatment with hydrogen peroxide, the pyroptosis-related proteins NLR family pyrin domain containing 3 (NLRP3), cleaved CASP-1, N-terminal fragment of gasdermin D (GSDMD-N), interleukin (IL)-18, and IL-1ß in NPCs were upregulated, and the number of propidium iodide (PI)-positive cells was also increased, which was able to be alleviated by pretreatment with melatonin. The protective effect of melatonin on pyroptosis was blunted by both the melatonin receptor antagonist luzindole and the nuclear factor erythroid 2-related factor 2 (Nrf2) inhibitor ML385. In addition, the expression of the transcription factor Nrf2 was up- or downregulated when the melatonin receptor was activated or blocked by melatonin or luzindole, respectively. Melatonin protects NPCs against reactive oxygen species-induced pyroptosis by upregulating the transcription factor Nrf2 via melatonin receptors.

Layer-by-layer assembly of procyanidin and collagen promotes mesenchymal stem cell proliferation and osteogenic differentiation in vitro and in vivo.

Collagen, commonly used in tissue engineering, is widespread in various tissues. During bone tissue regeneration, collagen can stimulate the cellular response and determine the fate of cells. In this work, we integrated collagen type II with procyanidin (PC) onto an implant coating by applying a layer-by-layer technique to demonstrate that collagen and PC can participate in the construction of new biomaterials and serve as multifunctional components. The effects of PC/collagen multilayers on the viability of cocultured bone marrow mesenchymal stem cells (BMSCs) were analyzed by cell counting kit-8 analysis and phalloidin staining. The reactive oxygen species level of BMSCs was revealed through immunofluorescent staining and flow cytometry. Osteogenesis-related genes were detected, and in vivo experiment was performed to reveal the effect of newly designed material on the osteogenic differentiation of BMSCs. Our data demonstrated that in BMSCs PC/collagen multilayers accelerated the proliferation and osteogenic differentiation through Wnt/ß-catenin signaling pathway and enhanced bone generation around the implant in the bone defect model of rabbit femurs. In summary, combination of collagen and PC provided a new sight for the research and development of implant materials or coatings in the future.

Identification of basement membrane-related biomarkers associated with the diagnosis of osteoarthritis based on machine learning.

BACKGROUND: Osteoarthritis is a very common clinical disease in middle-aged and elderly individuals, and with the advent of ageing, the incidence of this disease is gradually increasing. There are few studies on the role of basement membrane (BM)-related genes in OA. METHOD: We used bioinformatics and machine learning methods to identify important genes related to BMs in OA patients and performed immune infiltration analysis, lncRNA‒miRNA-mRNA network prediction, ROC analysis, and qRT‒PCR. RESULT: Based on the results of machine learning, we determined that LAMA2 and NID2 were the key diagnostic genes of OA, which were confirmed by ROC and qRT‒PCR analyses. Immune analysis showed that LAMA2 and NID2 were closely related to resting memory CD4 T cells, mast cells and plasma cells. Two lncRNAs, XIST and TTTY15, were simultaneously identified, and lncRNA‒miRNA‒mRNA network prediction was performed. CONCLUSION: LAMA2 and NID2 are important potential targets for the diagnosis and treatment of OA.

Engineering a mucin coating to promote osteogenic differentiation of BMSCs in vitro and bone formation in vivo through the Wnt/ß-catenin pathway.

Mucin, a family of glycoproteins, is widespread in the inner linings of various lumen organs and plays key roles in protecting epithelial cells from invasion by foreign species and communicating with the external environment. Here, we demonstrated that Mucin could be engineered as a promising building block in biomaterials with unexpected multifunctionalities by codepositing with procyanidin (PC, a kind of flavanol polyphenol) through a layer-by-layer technique. The process of generating PC/Mucin multilayers was well characterized and monitored, which was controllable by the assembly conditions. The behaviors of bone marrow mesenchymal stem cells (BMSCs), including proliferation, antioxidant ability, and expression of vinculin, were investigated to reveal the role of PC/Mucin multilayers on the osteogenic differentiation of BMSCs. Our data showed that PC/Mucin multilayers promoted osteogenesis-related genes (Col1, ON, OCN and RUNX2) in BMSCs in vitro and bone generation in vivo by activating the Wnt/ß-catenin pathway. These findings demonstrate that engineering Mucin might be a new route in the future to implant materials or coatings for bone regeneration.

Macrophage migration inhibitory factor protects bone marrow mesenchymal stem cells from hypoxia/ischemia-induced apoptosis by regulating lncRNA MEG3.

OBJECTIVES: This research was performed to explore the effect of macrophage migration inhibitory factor (MIF) on the apoptosis of bone marrow mesenchymal stem cells (BMSCs) in ischemia and hypoxia environments. METHODS: The cell viability of BMSCs incubated under hypoxia/ischemia (H/I) conditions with or without pretreatment with MIF or triglycidyl isocyanurate (TGIC) was detected using cell counting kit-8 (CCK-8) analysis. Plasmids containing long noncoding RNA (lncRNA) maternally expressed gene 3 (MEG3) or ß-catenin small interfering RNA (siRNA) were used to overexpress or downregulate the corresponding gene, and the p53 signaling pathway was activated by pretreatment with TGIC. The influences of MIF, overexpression of lncRNA MEG3, activation of the p53 signaling pathway, and silencing of ß-catenin on H/I-induced apoptosis of BMSCs were revealed by western blotting, flow cytometry, and terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) staining. RESULTS: From the results of CCK-8 assay, western blotting, and flow cytometry, pretreatment with MIF significantly decreased the H/I-induced apoptosis of BMSCs. This effect was inhibited when lncRNA MEG3 was overexpressed by plasmids containing MEG3. The p53 signaling pathway was activated by TGIC, and ß-catenin was silenced by siRNA. From western blot results, the expression levels of ß-catenin in the nucleus and phosphorylated p53 (p-p53) were downregulated and upregulated, respectively, when the lncRNA MEG3 was overexpressed. Through flow cytometry, MIF was also shown to significantly alleviate the increased reactive oxygen species (ROS) level of BMSCs caused by H/I. CONCLUSIONS: In summary, we conclude that MIF protected BMSCs from H/I-induced apoptosis by downregulating the lncRNA MEG3/p53 signaling pathway, activating the Wnt/ß-catenin signaling pathway, and decreasing ROS levels.

Overexpression of miR-338-5p in exosomes derived from mesenchymal stromal cells provides neuroprotective effects by the Cnr1/Rap1/Akt pathway after spinal cord injury in rats.

Growing evidence has shown that microRNAs (miRNAs) play crucial roles in the physiopathology of spinal cord injury (SCI). Recent studies have confirmed that miR-338-5p regulates myelination, suggesting a potential role in the treatment of SCI. However, the molecular mechanism of miR-338-5p on SCI is still unknown. Recently, exosomes have emerged as an ideal vector to deliver therapeutic molecules such as miRNAs. Here, we explored the effects of miR-338-5p-overexpressing exosomes derived from bone marrow-derived mesenchymal stromal cells (BMSCs) on SCI. In vivo, a model of contusion SCI in rats was established, and we observed that overexpression of miR-338-5p in exosomes profoundly increased the expression levels of neurofilament protein-M and growth-associated protein-43 and decreased those of myelin-associated glycoprotein and glial fibrillary acidic protein, which provided neuroprotective effects after acute SCI. In an in vitro study, we found that overexpression of miR-338-5p in exosomes repressed cell apoptosis following H2O2-induced oxidative stress injury in PC12 cells. Additionally, we confirmed that cannabinoid receptor 1 (Cnr1) was the target gene of miR-338-5p by dual-luciferase reporter assays and that Rap1 was the downstream gene by the KEGG pathway analysis. We found that miR-338-5p increased cAMP accumulation as a consequence of downregulated expression of the target gene Cnr1, and then, Rap1 was activated by cAMP. Eventually, the activation of the PI3K/Akt pathway attenuated cell apoptosis and promoted neuronal survival by cAMP-mediated Rap1 activation. In brief, these findings showed that exosomes overexpressing miR-338-5p were a promising treatment strategy for SCI.

Femoral Stress Changes after Total Hip Arthroplasty with the Ribbed Prosthesis: A Finite Element Analysis.

BACKGROUND: A total hip reconstruction is related to the stress distribution throughout the prosthesis, cement, and femur. Researches on reducing the stress in all components to minimize the risk of failure are of great significance. The objective of our study was to determine the biomechanical variation in overall femoral stress and periprosthetic femoral stress distribution after implantation with the Ribbed anatomic prosthesis. METHODS: Three-dimensional finite element models of intact femur and Ribbed prosthesis were developed according to the morphology, while the hip joint loading and the strength of related muscles were applied in the models. The overall stress changes of the intact femur before and after the implantation were analyzed, and the periprosthetic stress distribution especially in the proximal region of the femur was quantified. RESULTS: As a result, the overall stress pattern of the femur did not change after the implantation compared with the intact femur. The region of peak stress value was located in the middle and lower segments of the full length femur, but the stress value level decreased. The final prosthesis resulted in a significant decrease in the equivalent stress level of the periprosthetic bone tissue, and the most severe area appeared at the endmost posterior quadrant. The stress shielding ratio of the Ribbed prosthesis was 71.6%. The stress value level gradually increased towards the distal part of the prosthesis and recovered to physiological level at the end of the prosthesis. CONCLUSIONS: The Ribbed prosthesis can cause significant stress shielding effect in the proximal femur. These results may help optimize prosthetic design to reduce stress shielding effect and improve clinical outcomes.

Antitumor effects and mechanisms of pyropheophorbide­α methyl ester­mediated photodynamic therapy on the human osteosarcoma cell line MG­63.

Photodynamic therapy (PDT) is a promising treatment for osteosarcoma, and pyropheophorbide­α methyl ester (MPPa) is a second­generation photosensitizer for tumor treatment. The present study aimed to determine the efficacy and possible mechanisms of MPPa­PDT in the treatment of osteosarcoma MG­63 cells. Flow cytometry and western blotting were used to detect cell cycle­related indicators Cyclin D1, Cyclin E, Cyclin A and Cyclin B1. Cell migration and invasion abilities were detected using wound­healing and Transwell chamber assays. Cellular endoplasmic reticulum stress (ERS), autophagy and apoptosis­related indicators were detected by flow cytometry and western blotting. The results demonstrated that MPPa­PDT blocked the MG­63 cell cycle and inhibited cell migration and invasion. Additionally, MPPa­PDT inhibited the activation of the Akt/mammalian target of rapamycin (mTOR) pathway. MG­63 cells underwent ERS­induced apoptosis following MPPa­PDT treatment. Pretreatment with the mTOR phosphorylation inhibitor rapamycin affected the autophagy of MPPa­PDT­induced osteosarcoma MG­63 cells and enhanced apoptosis through targeting mTOR.

Protective effects of autophagy and NFE2L2 on reactive oxygen species-induced pyroptosis of human nucleus pulposus cells.

Intervertebral disc degeneration (IDD) is characterized by the decrease of nucleus pulposus cells (NPCs). With the increase of the degree of degeneration, the reactive oxygen species (ROS) in nucleus pulposus tissue increases. Pyroptosis is a newly discovered form of cell death and its relationship with oxidative stress in NPCs remains unclear. This study was performed to investigate the mechanisms of pyroptosis of NPCs under oxidative stress. NPCs were isolated from IDD patients by surgical treatment. Pyroptosis related proteins like NLR family pyrin domain containing 3(NLRP3) and PYD and CARD domain containing (PYCARD) were detected by western blot, and membrane pore formation was observed by hochest33342/PI double staining or scanning electron microscope. The results showed that ROS induced the pyroptosis of NPCs and it depended on the expression of NLRP3 and PYCARD. The increased ROS level also increased transcription factor nuclear factor, erythroid 2 like 2 (NFE2L2, Nrf2) and the autophagy of NPCs, both of which attenuated the pyroptosis. In summary, ROS induces the pyroptosis of NPCs through the NLRP3/ PYCARD pathway, and establishes negative regulation by increasing autophagy and NFE2L2. These findings may provide a better understanding of the mechanism of IDD and potential therapeutic approaches for IDD treatment.

Comparison of Clinical Efficacy of Lateral and Lateral and Medial Double-plating Fixation of Distal Femoral Fractures.

The present study was performed to compare the clinical efficacy of lateral plate and lateral and medial double-plating fixation of distal femoral fractures and explore the indication of lateral and medial double-plating fixation of the distal femoral fractures. From March 2006 to April 2014, 48 and 12 cases of distal femoral fractures were treated with lateral plate (single plate) and lateral and medial plates (double plates), respectively. During the surgery, after setting the lateral plate for the distal femoral fractures, if the varus stress test of the knee was positive and the lateral collateral ligament rupture was excluded, lateral and medial double-plating fixation was used for the stability of the fragments. All the patients were followed up at an average period of 15.9 months. The average operation time, the intraoperative hemorrhage and the fracture union time of the two groups were compared. One year after operation, knee function was evaluated by the Kolmert's standard. There was no significant difference in the average operation time, intraoperative hemorrhage, fracture healing time and excellent and good rates of postoperative knee function between two groups. Positive Varus stress test during operation can be an indication for lateral and medial double-plating fixation of distal femoral fractures.