This study investigates the mechanism of cell death induced by cadmium (Cd) in Chinese hamster ovary (CHO) cells. Cells exposed to 4 microM Cd for 24 h did not show signs of apoptosis, such as DNA fragmentation and caspase-3 activation. The pro-apoptotic (Bax) or anti-apoptotic (Bcl-2 and Bcl-xL) protein levels in the Bcl-2 family were not altered. However, an increase in propidium iodide uptake and depletion of ATP, characteristics of necrotic cell death, were observed. Cd treatment increased the intracellular calcium (Ca2+) level. Removal of the Ca2+ by a chelator, BAPTA-AM, efficiently inhibited Cd-induced necrosis. The increased Ca2+ subsequently mediated calpain activation and intracellular ROS production. Calpains then triggered mitochondrial depolarization resulting in cell necrosis. Cyclosporin A, an inhibitor of mitochondrial permeability transition, recovered the membrane potential and reduced the necrotic effect. The generated ROS reduced basal NF-kappaB activity and led cells to necrosis. An increase of NF-kappaB activity by its activator, PMA, attenuated Cd-induced necrosis. Calpains and ROS act cooperatively in this process. The calpain inhibitor and the ROS scavenger synergistically inhibited Cd-induced necrosis. Results in this study suggest that Cd stimulates Ca2+-dependent necrosis in CHO cells through two separate pathways. It reduces mitochondrial membrane potential by activating calpain and inhibits NF-kappaB activity by increasing the ROS level.

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Aging is associated with deteriorated sinoatrial (SA) node function. The pacemaker current (If) carried by hyperpolarization-activated, cyclic nucleotide-gated cation (HCN) channels plays a key role in the generation of spontaneous activity of the SA node cells. In the present study, the SA node cells were identified and isolated using the laser capture microdissection (LCM) technique for quantitative analysis of the HCN channel isoforms HCN1-HCN4 transcripts. Using real-time quantitative reverse transcription- polymerase chain reaction (RT-PCR), marked down-regulated transcriptions of HCN2 and HCN4 were observed in the SA node from young (1-month-old) to adult (4-month-old) and further to aged (30- month-old) rats. However, neither the HCN1 nor HCN3 transcript was detectable throughout the lifespan of the rat. Consistently, the effect of 2 mM Cs+ to selectively block the HCN channels, on pacemaking was also lessened with age. Our findings raise the possibility that the down-regulated transcription and relative function of HCN channels may contribute to the decline of the SA node function in aged rats.

Polyetheretherketone (PEEK) has been becoming a popular implant material in orthopaedic applications. The lack of bioactivity affects PEEK’s long-term lifetime, and appropriate surface modification is an effective way to enhance its bioactivity. Sulfonation of PEEK can endow PEEK with a 3 D porous network surface and improve its bioactivity. This study is aimed at exploring an optimal sulfonation time and a post-treatment method of PEEK sulfonation. PEEK was immersed into concentrated sulfuric acid for different sulfonation times and experienced different post-treatment methods to turn into sulfonated PEEK (SPEEK). The immersion times were 0.5 min (SPEEK0.5), 1 min (SPEEK1), 3 min (SPEEK3), 5 min (SPEEK5) and 7 min (SPEEK7), and the post-treatment methods were acetone rinsing (SPEEK-T1), hydrothermal treatment (SPEEK-T2) and NaOH immersion (SPEEK-T3). Scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), Fourier transform infrared spectroscopy, hydrophilic property, ion release and cell viability evaluations were performed to optimize the sulfonation time, and the SEM, EDS, ion release and cell viability were analysed to optimize the post-treatment method. The results showed a porous network structure was formed on all samples of SPEEK, and the porous structure became more obvious and the S concentration increased with increasing sulfonation time. However, too long of an immersion time (SPEEK7) tended to damage the superficial porous structure and left a higher content of sulfuric acid, which could inhibit the growth of MC3T3E1 cells on its surface. In addition, the surface morphology, residual sulfuric acid and cytocompatibility of SPEEK-T1, SPEEK-T2 and SPEEK-T3 were not distinctly different. In conclusion, a 5-min sulfonation time was considered to be the optimal selection, and acetone rinsing, hydrothermal treatment and NaOH immersion showed the same effect in removing the residual sulfuric acid. The understanding of optimal sulfonation time and post-treatment method can provide a theoretical basis in preparing SPEEK for orthopaedic applications.

Background Hemarthrosis after anterior cruciate ligament (ACL) reconstruction can create many adverse joint effects. Tranexamic acid (TXA) can be used to minimize hemarthrosis and associated pain after ACL reconstruction. We aimed to compare the efficacies of intravenous (IV) administration and intra-articular (IA) injection of TXA during ACL reconstruction for reducing postoperative hemarthrosis. Methods A total of 120 patients who underwent arthroscopic ACL reconstruction were included in this prospective and randomized study. All patients were randomized into three groups: IV group, IA group and placebo group. Patients in the IV group received intravenously administered TXA (15 mg/kg in 100 mL of saline solution) 10 min before tourniquet release; patients in the IA group received intra-articular TXA (15 mg/kg in 100 mL of saline solution) injected via the drainage tube; and patients in the placebo group received an equivalent volume of normal saline administered into the knee joint cavity and intravenously. Drainage tubes were removed 24 h after surgery, and all enrolled patients experienced a 4-week follow-up period. The drain output volume, visual analogue scale (VAS) score, patellar circumference, hemarthrosis grade and Lysholm score of all patients were recorded. Results Both the IV group and the IA group had significantly lower drain output volumes at day 1, lower VAS scores at weeks 1 and 2, smaller patellar circumferences at weeks 1 and 2, and lower hemarthrosis grades at weeks 1 and 2 than the placebo group (p < 0.05). There were no significant differences in drain output volume, VAS score, patellar circumference or hemarthrosis grade between the IV group and the IA group at any time point (p > 0.05). No obvious differences in Lysholm score were observed between any pair of groups at week 4 (p > 0.05)). Neither infection nor deep vein thrombosis occurred in any group. Conclusions Both intravenous administration and intra-articular injection can reduce intra-articular hemarthrosis, joint pain and swelling during ACL reconstruction. No significant difference in the efficacies of reducing hemarthrosis, joint pain and swelling was found between intravenous administration and intra-articular injection. Trial registration The study was registered by the Chinese Clinical Trial Registry (The comparative efficacies of intravenous administration and intra-articular injection of tranexamic acid during anterior cruciate ligament reconstruction; ChiCTR-INR-17012217; August 1, 2017).

Lymph node (LN) metastasis at an early stage of cervical cancer is often an indicator of poor prognosis and is critical for subsequent adjuvant therapy. The current study aimed to identify aberrant gene signatures and biomarkers of metastasis for patients with cervical cancer. RNA-sequencing data of 132 LN negative (N0) and 60 LN positive (N1) cervical cancer samples obtained from The Cancer Genome Atlas database were analyzed. Differentially expressed genes were identified using R packages 'edgeR' and 'limma'. Kyoto Encyclopedia of Genes and Genomes pathway enrichment and Gene Set Enrichment Analysis (GSEA) were conducted. The GSE9750 dataset obtained from Gene Expression Omnibus was analyzed to identify genes that are persistently aberrantly expressed during the development of cervical cancer. The peroxisome proliferator-activated receptor (PPAR) signaling pathway was screened out to be significant during LN metastasis. In the two analyzed datasets, 11 genes were aberrantly expressed, while matrix metalloproteinase 1 (MMP1) was the only gene that was persistently overexpressed. Cell viability, wound healing and Transwell assays were performed to evaluate the effects of MMP1 knockdown in cervical cancer cell lines, and the expression of epithelial mesenchymal transition (EMT) markers was detected. Finally, the clinical significance of MMP1 was investigated. The current study identified that MMP1 was overexpressed and the PPAR signaling pathway was associated LN metastasis in patients with cervical cancer. Following knockdown of MMP1, the proliferation, migration and invasion of cervical cancer cell lines were weakened, the expression of epithelial marker E-cadherin was increased, and the expression of metastasis-associated gene vimentin was decreased. MMP1 was an independent prognostic factor for cervical cancer. The current study indicated that MMP1 has a key role in the regulation of cervical tumor growth and LN metastasis via EMT to a certain extent. The results suggest that MMP1 may be a biomarker for LN metastasis of cervical cancer, and further validation should be performed.

Accumulating evidence indicates that dysregulation of miRNAs could contribute to tumor growth and metastasis of chondrosarcoma by infuencing cell proliferation and invasion. In the current study, we are interested to examine the role of miRNAs in the carcinogenesis and progression of chondrosarcoma. Here, using comparative miRNA profiling of tissues and cells of chondrosarcoma and cartilage, we identified miR-494 as a commonly downregulated miRNA in the tissues of patients with chondrosarcoma and chondrosarcoma cancer cell line, and upregulation of miR-494 could inhibit proliferation and invasion of chondrosarcoma cancer cells in vivo and in vitro. Moreover, our data demonstrated that SOX9, the essential regulator of the process of cartilage differentiation, was the direct target and functional mediator of miR-494 in chondrosarcoma cells. And downregulation of SOX9 could also inhibit migration and invasion of chondrosarcoma cells. In the last, we identified low expression of miR-494 was significantly correlated with poor overall survival and prognosis of chondrosarcoma patients. Thus, miR-494 may be a new common therapeutic target and prognosis biomarker for chondrosarcoma.

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