Objective To establish the models with human rheumatoid arthritis (RA) synovial fibroblasts (RASFs)-cartilage-severe combined immune deficient (SCID) mice for the study of the RASFs in the pathogenesis of RA.Methods The 4th passage RASFs were marked with 5-bromodexyuridine (5-Brdu)and injected into a cavity of inert sterile gel sponge,then with the normal human cartilage co-implanted in the back subcutaneously of SCID mice to set up a novel model of RA.Osteoarthritis synovial fibroblasts (OASFs)were injected as control group.Thirty days after the surgery,the mice were killed,the grafts and the knee joints were proceed with histological study and immunohistochemistry to detect the expression of 5-Brdu and Vimentin in synoviocytes.The serum level of interleukin (IL)-6 and matrix metalloproteinase (MMP)-3 were detected with enzyme-linked immunosorbent assay (ELISA).Results Twenty-three mice survived except for one mouse in the RASFs group died of anesthesia.① Only in one case in the RASFs group,the IL-6 was detected,the others were unable to be detected.The MMP-3 in the OASFs group was (40±17) pg/ml,but in RASFs group only one case was detected.② There were 4 and 3 implanted cartilages loss in the RASFs group and OASFs group respectively.The histological scores of cartilage invasion by synoviocytes and cartilage degradation in grafts were higher in RASFs groups than in OASFs groups (0.6±0.7 vs 0.3±0.5,2.3±0.8 vs 1.7±1.0 respectively).③ The histological scores of synovial hyperplasia and cartilage invasion in the knee joints was significantly higher in the RASFs group than in the OASFs group (3.1±0.8 vs 1.7±1.0,P＜0.01,1.6±1.7 vs 0.6±1.4,P＜0.05 respectively).④ During the grafts,a lot of 5-Brdu and Vimentin markers positive synovio-cytes were found in the mice subcutaneous tissue,but manipulus positive synoviocytes were found on the area of cartilage invasion in both groups.In knee joints,single positive synoviocytes could be detected in bone marrow and hyperplasic area of the synovial tissue in both groups.Conclusion The isolated RASFs can survival and have the ability to invade and degrade the cartilage in vivo without the limitation of immunity induced inflammations,and can also migrate to the synovial joints in distance and induce arthritis.

Objective:To investigate the role of NG2 cells in generating and maintaining neuropathic pain in rats after spinal cord injury (SCI).Methods:According to random number table method, 100 healthy adult male SD rats were divided into control group ( n=20, without any intervention), sham-operated group ( n=40, exposed T 10 segment without spinal cord impact) and SCI group ( n=40, exposed T 10 segment and constructed SCI model by improved Allen's method). One d before, and 14, 21 and 28 d after surgery, Von Frey fiber probe was used to detect the rat hindlimb mechanical withdrawal threshold (MWT); immunofluorescent staining was used to detect the proportion of NG2-positive cells in spinal dorsal horn cells; Western blotting was used to detect chondroitin sulfate proteoglycan (CSPG) expression in spinal dorsal horn of rats. Results:Fourteen, 21 and 28 d after surgery, SCI group had significantly lower hindlimb MWT, and significantly higher proportion of NG2-positive cells in spinal dorsal horn cells and CSPG expression in spinal dorsal horn than control group and sham-operated group ( P<0.05). One d before, and 14, 21 and 28 d after surgery, in SCI group, hindlimb MWT decreased firstly and increased secondly, proportion of NG2-positive cells in spinal dorsal horn cells increased firstly and decreased secondly, and CSPG expression in spinal dorsal horn increased firstly and decreased secondly. Except for those 21 and 28 d after surgery, hindlimb MWT, proportion of NG2-positive cells in spinal dorsal horn cells, and CSPG expression in spinal dorsal horn showed significant differences between each two time points ( P<0.05). In SCI group, hindlimb MWT was negatively correlated with proportion of NG2-positive cells in spinal dorsal horn cells ( r=-0.876, P<0.001), and CSPG expression was positively correlated with proportion of NG2-positive cells in spinal dorsal horn cells ( r=0.927, P<0.001). Conclusion:NG2 cell proliferation and increased CSPG expression secreted by NG2 cells in spinal cord tissues after SCI generate and maintain neuropathic pain.

Objective    To systematically evaluate the risk factors for hypoxemia after coronary artery bypass grafting (CABG). Methods    Eight electronic databases including PubMed, EMbase, CENTRAL, Web of Science, CNKI, CBM, VIP and Wanfang data were searched by computer to collect cochort and case-control studies about CABG and hypoxemia published from inception to March 2020. Two authors independently assessed the quality using the Newcastle-Ottawa Scale (NOS), and a meta-analysis was performed by RevMan 5.3 software. Results    A total of 15 studies involving 4 277 patients were included in this study and among them 1 273 patients suffered hypoxemia. Meta-analysis showed that age (OR=1.55, 95%CI 1.22 to 1.96, P=0.000 3), smoking (OR=3.22, 95%CI 2.48 to 4.17, P<0.000 01), preoperative chronic pulmonary diseases (OR=4.75, 95%CI 3.28 to 6.86, P<0.000 01), diabetes (OR=2.49, 95%CI 1.86 to 3.33, P<0.000 01), left ventricular ejection fraction (OR=3.15, 95%CI 2.19 to 4.52, P<0.000 01), number of coronary artery lesions (OR=2.20, 95%CI 1.63 to 2.97, P<0.000 1) were independent risk factors for hypoxemia after CABG; body mass index (OR=1.31, 95%CI 0.97 to 1.77, P=0.08) and cardiopulmonary bypass time (OR=3.40, 95%CI 0.72 to 15.94, P=0.12) were not associated with hypoxemia. Conclusion    Current evidence shows that age, preoperative chronic pulmonary diseases, smoking, diabetes, left ventricular ejection fraction, number of coronary artery are risk factors for hypoxemia after CABG, which can be used to identify high-risk patients and provide guidance for medical staff to develop perioperative preventive strategies to reduce the incidence of hypoxemia. The results should be validated by large-scale standard studies in the future.