Mitomycin C induces apoptosis in rheumatoid arthritis fibroblast-like synoviocytes via a mitochondrial-mediated pathway.

BACKGROUND/AIMS: Rheumatoid arthritis (RA) is a systemic chronic inflammatory disease characterised by prominent synoviocyte hyperplasia and a potential imbalance between the growth and death of fibroblast-like synoviocytes (FLS). Mitomycin C (MMC) has previously been demonstrated to inhibit fibroblast proliferation and to induce fibroblast apoptosis. However, the effects of MMC on the proliferation and apoptosis of human RA FLS and the potential mechanisms underlying its effects remain unknown. METHODS: Cell viability was determined using the Cell Counting Kit-8 assay. Apoptotic cell death was analysed via Annexin V-FITC/PI double staining and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick-end labelling. The production of intracellular reactive oxygen species (ROS) was assessed via flow cytometry, and the changes in mitochondrial membrane potential (ΔΨm) were visualized based on JC-1 staining via fluorescence microscopy. The expression of apoptosis-related proteins was determined via Western blot. RESULTS: Treatment with MMC significantly reduced cell viability and induced apoptosis in RA FLS. Furthermore, MMC exposure was found to stimulate the production of ROS and to disrupt the ΔΨm compared to the control treatment. Moreover, MMC increased the release of mitochondrial cytochrome c, the ratio of Bax/Bcl-2, the activation of caspase-9 and caspase-3, and the subsequent cleavage of poly(ADP-ribose) polymerase. CONCLUSION: Our findings suggest that MMC inhibits cell proliferation and induces apoptosis in RA FLS, and the mechanism underlying this MMC-induced apoptosis may involve a mitochondrial signalling pathway.

Sustained static stress-induced chondrocyte apoptosis in the rat cervical vertebral growth plate and its signal transduction mechanisms.

Apoptosis of the vertebral growth plate chondrocytes plays an important role in the pathogenesis of intervertebral disk degeneration. In this paper, we have successfully established an experimental model induced by static stress and provided a useful method to study the mechanisms of chondrocyte apoptosis.A sustained static load of C0.2 MPa over at least 12 h was observed to induce chondrocyte apoptosis, up-regulation of bax and caspase-3 expression, and down-regulation of bcl-2 expression.

Sustained static stress-induced chondrocyte apoptosis in the rat cervical vertebral growth plate and its signal transduction mechanisms.

Apoptosis of the vertebral growth plate chondrocytes plays an important role in the pathogenesis of intervertebral disk degeneration. In this paper, we have successfully established an experimental model induced by static stress and provided a useful method to study the mechanisms of chondrocyte apoptosis. A sustained static load of ≥0.2 MPa over at least 12 h was observed to induce chondrocyte apoptosis, up-regulation of bax and caspase-3 expression, and down-regulation of bcl-2 expression.

Apoptosis of endplate chondrocytes in post-laminectomy cervical kyphotic deformity. An in vivo animal model in sheep.

PURPOSE: The present study was performed to establish an animal model of cervical kyphosis after laminectomy (C2-C5), and to determine the role of endplate chondrocytes apoptosis in cervical kyphosis after laminectomy. METHODS: Twenty-four 3-month-old sheep were randomly divided into two groups: the laminectomy group (n = 12), and the control group (n = 12). The cervical spine alignment was evaluated on a lateral cervical spine X-ray using Harrison's posterior tangent method before surgery and at follow-up. Cartilaginous endplate chondrocyte apoptosis was confirmed using transmission electron microscopy and terminal deoxyribonucleotidyl transferase (TdT)-mediated dUTP nick-end labelling. RESULTS: The mean preoperative cervical curvature (C2-5) in the surgery group was -15.8°. The cervical curvature was 19.1° at 3 months post-operation and decreased to 20.2° at the final follow-up postoperatively. The cervical curvature was significantly decreased in the laminectomy group compared with the control group at the last follow-up (P < 0.001), which was a direct indication of kyphotic change. The incidence of apoptotic cells in the surgery group was significantly higher at the 3- and 6-month follow-up than the incidence in the control group. CONCLUSIONS: The frequency of endplate chondrocyte apoptosis in the laminectomy group was significantly higher than in the control group, indicating that chondrocyte apoptosis may play a pivotal role in the progress of post-laminectomy cervical kyphosis.

Diagnostic value of intraoperative tap test for acute deltoid ligament injury.

PURPOSE: Deltoid ligament injuries appear with isolated or even no displacement of the lateral malleolus fracture which could easily lead to misdiagnosis, which frequently brings about ankle medial instability and talus shift that eventually lead to the occurrence of ankle osteoarthritis. This study is aimed to investigate the value of the tap test for assessing the integrity of the deltoid ligament intraoperatively. METHODS: Ninety-two patients with malleolar fractures and possible acute deltoid ligament injury treated in our hospital from March 2013 to May 2016 were enrolled in this prospective study. The gravity stress test and tap test were performed preoperatively by three physicians independently before and after fixation of the fibula. The sensitivity, specificity, positive and negative predictive values, and false-positive and false-negative rates of both tests were determined based on medial malleolus exploration for the integrity of the deltoid ligament. The inter-observer consistency was also analyzed. RESULTS: Forty seven (51.1%) versus fifty two (56.5%) of the 92 patients tested positive for deltoid ligament injury according to the preoperative gravity stress test or the subsequent tap test. Forty-eight cases (52.2%) were confirmed during surgery. The sensitivity of gravity stress test was lower than that of tap test (95.8% vs 100%), and specificity of gravity stress test was the same as tap test (97.7% vs 97.7%). Between gravity stress test and tap test, the positive and negative predictive values were 97.9% vs 92.3% and 95.6% vs 100%, and the false-positive and false-negative rates were 2.3% vs 9.09% and 4.2% vs 0%, respectively. Between the two tests results, the percentage of inter-observer agreement was > 90% (kappa coefficient > 0.80). CONCLUSION: The tap test has the advantages of high sensitivity, simple operation, and less radiation exposure, suggesting that it is of high diagnostic value for assessing the integrity of the acute deltoid ligament.

Xanthohumol Inhibited Mechanical Stimulation-Induced Articular ECM Degradation by Mediating lncRNA GAS5/miR-27a Axis.

Osteoarthritis (OA) is histopathologically marked by extracellular matrix (ECM) degradation in joint cartilage. Abnormal mechanical stimulation on joint cartilage may result in ECM degeneration and OA development. Matrix metalloproteinase 13 (MMP-13) is one of the catabolic enzymes contributing to the degradation of ECM, and it has become the potential biomarker for the therapeutic management of OA. Xanthohumol (XH), a naturally occurring prenylflavonoid derived from hops and beer, shows the protective activity against OA development. However, the potential mechanisms still need great effort. In this article, mechanical stimulation could significantly increase the expression of MMP-13 and lncRNA GAS5 (GAS5) and promoting ECM degradation. These could be effectively reversed by XH administration. Suppressed expression GAS5 ameliorated mechanical stimulation-induced MMP-13 expression. MiR-27a was predicted and verified as a target of GAS5, and overexpression of miR-27a down regulated the expression of MMP-13. Collectively, XH exhibited protective effects against mechanical stimulation-induced ECM degradation by mediating the GAS5/miR-27a signaling pathway in OA chondrocytes.

Bimetallic phosphide decorated Mo-BiVO4 for significantly improved photoelectrochemical activity and stability.

Bismuth vanadate photoanode has shown great potential for photoelectrochemical (PEC) catalysis, but it needs to be further modified because of its relatively low charge-separation efficiency and poor stability. Herein, the bimetallic phosphide NiCoP decorated Mo-BiVO4 is fabricated through the electrodeposition and drop-casting method, which significantly improves the charge separation and surface oxidation reaction. Therefore, the fabricated NiCoP/Mo-BiVO4 photoanode exhibits a low onset potential of 0.21 V (vs. RHE) and high photocurrent of 3.21 mA cm-2 at 1.23 V (vs. RHE), which is 3.12 times higher than that of pure BiVO4. Importantly, the decoration of NiCoP significantly improve the stability of BiVO4 photoanode.

[Immobilization impact of different fixatives on heavy metals contaminated soil].

Four kinds of amendments including humus, ammonium sulfate, lime, superphosphate and their complex combination were added to rapid immobilize the heavy metals in contaminated soils. The best material was chosen according to the heavy metals' immobilization efficiency and the Capacity Values of the fixative in stabilizing soil heavy metals. The redistributions of heavy metals were determined by the European Communities Bureau of Referent(BCR) fraction distribution experiment before and after treatment. The results were as follows: (1) In the single material treatment, lime worked best with the dosage of 2% compared to the control group. In the compound amendment treatments, 2% humus combined with 2% lime worked best, and the immobilization efficiency of Pb, Cu, Cd, Zn reached 98.49%, 99.40%, 95.86%, 99.21%, respectively. (2) The order of Capacity Values was lime > humus + lime > ammonium sulfate + lime > superphosphate > ammonium sulfate + superphosphate > humus + superphosphate > humus > superphosphate. (3) BCR sequential extraction procedure results indicated that 2% humus combined with 2% lime treatment were very effective in immobilizing heavy metals, better than 2% lime treatment alone. Besides, Cd was activated firstly by 2% humus treatment then it could be easily changed into the organic fraction and residual fraction after the subsequent addition of 2% lime.

Position and complications of pedicle screw insertion with or without image-navigation techniques in the thoracolumbar spine: a meta-analysis of comparative studies.

Computer-navigated pedicle screw insertion is applied to the thoracic and lumbar spine to attain high insertion accuracy and a low rate of screw-related complications. However, some in vivo and in vitro studies have shown that no advantages are gained with the use of navigation techniques compared to conventional techniques. Additionally, inconsistent conclusions have been drawn in various studies due to different population characteristics and methods used to assess the accuracy of screw placement. Moreover, it is not clear whether pedicle screw insertion with navigation techniques decreases the incidence of screw-related complications. Therefore, this study was sought to perform a meta-analysis of all available prospective evidence regarding pedicle screw insertion with or without navigation techniques in human thoracic and lumbar spine. We considered in vivo comparative studies that assessed the results of pedicle screw placement with or without navigation techniques. PubMed, Ovid MEDLINE and EMBASE databases were searched. Three published randomized controlled trials (RCTs) and nine retrospective comparative studies met the inclusion criteria. These studies included a total of 732 patients in whom 4,953 screws were inserted. In conclusion, accuracy of the position of grade I, II, III and IV screws and complication rate related to pedicle screw placement were significantly increased when navigation techniques were used in comparison to conventional techniques. Future research in this area should include RCTs with well-planned methodology to limit bias and report on validated, patient-based outcome measures.

Static mechanical stress induces apoptosis in rat endplate chondrocytes through MAPK and mitochondria-dependent caspase activation signaling pathways.

Mechanical stress has detrimental effects on cartilaginous endplate chondrocytes due to apoptosis in vivo and in vitro. In this study, we investigated the possible apoptosis signaling pathways induced by mechanical stress in cultured rat cervical endplate chondrocytes. Static mechanical load significantly reduced cell viability in a time- and load-dependent manner, as demonstrated by the Cell Counting Kit-8 (CCK-8) assay. Chondrocyte apoptosis induced by mechanical stress was confirmed by annexin V/propidium iodide (PI) staining and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL). Western blot analysis revealed that static load-induced chondrocyte apoptosis was accompanied by increased phosphorylation of c-Jun N-terminal kinase (JNK), extracellular signal-regulated kinase 1/2 (ERK1/2), and p38 mitogen-activated protein kinase (MAPK). The loss of mitochondrial membrane potential (ΔΨm), increased Cytochrome c release, and activated Caspase-9 and Caspase-3, indicating that the mitochondrial pathway is involved in mechanical stress-induced chondrocyte apoptosis. Treatment with inhibitors of JNK (SP600125), p38 MAPK (SB203580), and ERK (PD98059) prior to mechanical stimulation reversed both the static load-induced chondrocyte apoptosis and the activation of JNK, p38 MAPK, and ERK. Taken together, the data presented in this study demonstrate that mechanical stress induces apoptosis in rat cervical endplate chondrocytes through the MAPK-mediated mitochondrial apoptotic pathway.

Rapid identification of spinal ventral and dorsal roots using a quartz crystal microbalance.

The fast and accurate identification of nerve tracts is critical for successful nerve anastomosis. Taking advantage of differences in acetylcholinesterase content between the spinal ventral and dorsal roots, we developed a novel quartz crystal microbalance method to distinguish between these nerves based on acetylcholinesterase antibody reactivity. The acetylcholinesterase antibody was immobilized on the electrode surface of a quartz crystal microbalance and reacted with the acetylcholinesterase in sample solution. The formed antigen and antibody complexes added to the mass of the electrode inducing a change in frequency of the electrode. The spinal ventral and dorsal roots were distinguished by the change in frequency. The ventral and dorsal roots were cut into 1 to 2-mm long segments and then soaked in 250 µL PBS. Acetylcholinesterase antibody was immobilized on the quartz crystal microbalance gold electrode surface. The results revealed that in 10 minutes, both spinal ventral and dorsal roots induced a frequency change; however, the frequency change induced by the ventral roots was notably higher than that induced by the dorsal roots. No change was induced by bovine serum albumin or PBS. These results clearly demonstrate that a quartz crystal microbalance sensor can be used as a rapid, highly sensitive and accurate detection tool for the quick identification of spinal nerve roots intraoperatively.

Tacrolimus reduces scar formation and promotes sciatic nerve regeneration.

A sciatic nerve transection and repair model was established in Sprague-Dawley rats by transecting the tendon of obturator internus muscle in the greater sciatic foramen and suturing with nylon sutures. The models were treated with tacrolimus gavage (4 mg/kg per day) for 0, 2, 4 and 6 weeks. Specimens were harvested at 6 weeks of intragastric administration. Masson staining revealed that the collagen fiber content and scar area in the nerve anastomosis of the sciatic nerve injury rats were significantly reduced after tacrolimus administration. Hematoxylin-eosin staining showed that tacrolimus significantly increased myelinated nerve fiber density, average axon diameter and myelin sheath thickness. Intragastric administration of tacrolimus also led to a significant increase in the recovery rate of gastrocnemius muscle wet weight and the sciatic functional index after sciatic nerve injury. The above indices were most significantly improved at 6 weeks after of tacrolimus gavage. The myelinated nerve fiber density in the nerve anastomosis and the sciatic nerve functions had a significant negative correlation with the scar area, as detected by Spearman's rank correlation analysis. These findings indicate that tacrolimus can promote peripheral nerve regeneration and accelerate the recovery of neurological function through the reduction of scar formation.