Effects of SIRT1 gene knock-out via activation of SREBP2 protein-mediated PI3K/AKT signaling on osteoarthritis in mice / 华中科技大学学报（医学）（英德文版）

This study investigated the effects of SIRT1 gene knock-out on osteoarthritis in mice, and the possible roles of SREBP2 protein and the PI3K/AKT signaling pathway in the effects. Mice were randomly divided into a normal group and a SIRT1 gene knock-out group (6 mice in each group). In these groups, one side of the knee anterior cruciate ligament was traversed, and the ipsilateral medial meniscus was cut to establish an osteoarthritis model of knee joint. The countralateral synovial bursa was cut out, serving as controls. The knee joint specimens were then divided into four groups: SIRT1control group (group A, n=6); SIRT1osteoarthritis group (group B, n=6); SIRT1control group (group C, n=6); SIRT1osteoarthritis group (group D, n=6). HE staining, Masson staining, Safranin O-Fast Green staining and Van Gieson staining were used to observe the morphological changes in the articular cartilage of the knee. Immunohistochemical staining was employed to detect the expression of SIRT1, SREBP2, VEGF, AKT, HMGCR and type II collagen proteins. SA-β-gal staining was utilized to evaluate chondrocyte aging. The results showed clear knee joint cartilage destruction and degeneration in the SIRT1osteoarthritis group. The tidal line was twisted and displaced anteriorly. Type II collagen was destroyed and distributed unevenly. Compared with the SIRT1osteoarthritis group and SIRT1control group, SIRT1 protein expression was not obviously changed in the SIRT1osteoarthritis group (P>0.05), while the expression levels of the SREBP2, VEGF and HMGCR proteins were significantly increased (P<0.05) and the levels of AKT and type II collagen proteins were significantly decreased (P<0.05). SIRT1 gene knock-out may aggravate cartilage degeneration in osteoarthritis by activating the SREBP2 protein-mediated PI3K/AKT signalling pathway, suggesting that SIRT1 gene may play a protective role against osteoarthritis.

Inhibitory effects of SRT1720 on the apoptosis of rabbit chondrocytes by activating SIRT1 via p53/bax and NF-κB/PGC-1α pathways / 华中科技大学学报（医学）（英德文版）

SRT1720, a new discovered drug, was reported to activate silent information regulator 1 (SIRT1) and inhibit the chondrocyte apoptosis. However, the underlying mechanism remains elusive. In the present study, the chondrocytes were extracted from the cartilage tissues of New Zealand white rabbits, cultured in the presence of sodium nitroprusside (SNP) (2.5 mmol/L) and divided into five groups: 1, 5, 10, and 20 μmol/L SRT1720 groups and blank control group (0 μmol/L SRT1720). MTT assay was used to detect the chondrocyte viability and proliferation, and DAPI staining and flow cytometry to measure the chondrocyte apoptosis. The expression levels of SIRT1, p53, NF-κB/p65, Bax, and peroxisome proliferator-activated receptor gamma coactivator 1-α (PGC-1α) were detected by Western blotting and the expression levels of SIRT1, type II collagen, and aggrecan mRNA by RT-PCR. The results showed that in the SRT1720-treated groups, the nuclei of chondrocytes were morphologically intact and had uniform chromatin. In the blank control group, nuclear rupture into debris was observed in chondrocytes. With the SRT1720 concentration increasing, the chondrocyte viability increased, the apoptosis rate decreased, the protein expression levels of SIRT1 and PGC-1α and the mRNA expression levels of type II collagen and aggrecan increased ({ptP}<0.05), and the expression levels of p53, NF-κB and bax decreased (P<0.05). It was suggested that SRT1720 inhibits chondrocyte apoptosis by activating the expression of SIRT1 via p53/bax and NF-κB/PGC-1α pathways.

Influences of IL-6R antibody on PMMA bone cement-mediated expression of OPG and RANKL in synovial fibroblasts / 华中科技大学学报（医学）（英德文版）

Effect of interleukin-6 receptor (IL-6R) antibody on polymethyl methacrylate (PMMA) bone cement-mediated expression of osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB ligand (RANKL) in synovial fibroblasts was investigated. Synovial tissue obtained from total knee arthroplasty was digested and cultured. Inverted microscope was employed to observe the synovial cells and immunocytochemistry (SABC method) staining was used to identify synovial fibroblasts. This experiment was divided into three groups according to different culture media: PMMA group (75 μg/mL PMMA bone cement particles), IL-6R antibody group (10 ng/mL IL-6R antibody+75 μg/mL PMMA bone cement particles), and control group (no IL-6R antibody or PMMA bone cement particles). Influence of IL-6R antibody and PMMA on proliferation of synovial fibroblasts was measured by cell counting kit-8 (CCK-8). ELISA method was used to measure OPG and RANKL levels in culture solution. Fluorescence quantitative real-time PCR (FQ-PCR) was used to detect the expression of OPG and RANKL mRNA. After three consecutive passages, more than 95% of the primary synovial cells became long spindle fibroblast-like cells. SABC staining results showed that the fibroblast-like cells were negative for anti-CD68 antibody and positive for anti-vimentin antibody, with brown madder stained. CCK-8 test demonstrated that the absorbance (A) value at 450 nm was significantly lower in IL-6R antibody group than in PMMA group and control group (P0.05). Results of ELISA indicated that the expression of OPG was significantly higher in IL-6R antibody group than in PMMA group and control group (P0.05), but the expression of RANKL was higher in PMMA group than in control group (P0.05). IL-6R antibody could significantly increase the expression of OPG, but inhibit the expression of RANKL, which might provide a theoretical basis of molecular biology for the prevention and treatment of aseptic loosening of prosthesis.

Influences of IL-6R antibody on PMMA bone cement-mediated expression of OPG and RANKL in synovial fibroblasts / 华中科技大学学报（医学）（英德文版）

Effect of interleukin-6 receptor (IL-6R) antibody on polymethyl methacrylate (PMMA) bone cement-mediated expression of osteoprotegerin (OPG) and receptor activator of nuclear factor-kappaB ligand (RANKL) in synovial fibroblasts was investigated. Synovial tissue obtained from total knee arthroplasty was digested and cultured. Inverted microscope was employed to observe the synovial cells and immunocytochemistry (SABC method) staining was used to identify synovial fibroblasts. This experiment was divided into three groups according to different culture media: PMMA group (75 μg/mL PMMA bone cement particles), IL-6R antibody group (10 ng/mL IL-6R antibody+75 μg/mL PMMA bone cement particles), and control group (no IL-6R antibody or PMMA bone cement particles). Influence of IL-6R antibody and PMMA on proliferation of synovial fibroblasts was measured by cell counting kit-8 (CCK-8). ELISA method was used to measure OPG and RANKL levels in culture solution. Fluorescence quantitative real-time PCR (FQ-PCR) was used to detect the expression of OPG and RANKL mRNA. After three consecutive passages, more than 95% of the primary synovial cells became long spindle fibroblast-like cells. SABC staining results showed that the fibroblast-like cells were negative for anti-CD68 antibody and positive for anti-vimentin antibody, with brown madder stained. CCK-8 test demonstrated that the absorbance (A) value at 450 nm was significantly lower in IL-6R antibody group than in PMMA group and control group (P<0.01), but there was no statistically significant difference in A value at 450 nm between the control group and PMMA group (P>0.05). Results of ELISA indicated that the expression of OPG was significantly higher in IL-6R antibody group than in PMMA group and control group (P<0.01). The expression of RANKL was inhibited (P<0.05), and the ratio of OPG/RANKL was significantly increased in IL-6R antibody group as compared with PMMA group and control group. There was no significant difference in the expression of OPG between control group and PMMA group (P>0.05), but the expression of RANKL was higher in PMMA group than in control group (P<0.05), and there was a significant difference in the ratio of OPG/RANKL between them (P<0.05). Results of FQ-PCR revealed the expression of RANKL mRNA was significantly inhibited (P<0.01) and the expression of OPG mRNA was significantly increased (P<0.01) in IL-6R antibody group as compared with PMMA group and control group. The expression of RANKL mRNA was higher in PMMA group than in control group (P<0.05), but the expression of OPG mRNA had no significant difference between them (P>0.05). IL-6R antibody could significantly increase the expression of OPG, but inhibit the expression of RANKL, which might provide a theoretical basis of molecular biology for the prevention and treatment of aseptic loosening of prosthesis.

Construction of eukaryotic expression vectors of basic fibroblast growth factor and transfection in rabbit bone marrow stromal cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate approach and possibility of transferring basic fibroblast growth factor (bFGF) gene into rabbit bone marrow stromal cells (BMSCs).</p><p><b>METHODS</b>The eukaryotic expression vectors harboring bFGF cDNA were constructed and transfected into rabbit BMSCs mediated by liposome. The transcription and expression of bFGF gene in the transfected BMSCs were detected by means of morphological observation, immunohistochemistry, enzyme-linked immunosorbent assay (ELISA) and RT-PCR. The changes in the biological characteristics of the transfected MSCs were also observed.</p><p><b>RESULTS</b>Stable overexpression of bFGF protein was detected in the transfected BMSCs, which showed differentiation towards chondrocyte lineage.</p><p><b>CONCLUSION</b>Stable expression of bFGF gene in transfected BMSCs can induce cell differentiation into chondrocyte lineage.</p>

Biocompatibility of polylactic-co-glycolic acid for culturing bFGF gene-transfected bone marrow stromal cells and application of the cell complex for repairing rabbit cartilage defect / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the biocompatibility of polylactic-co-glycolic acid (PLGA) for culturing bFGF gene-transfected bone marrow stromal cells (BMSCs) and assess the feasibility of this cell complex for repairing cartilage defect in rabbits using tissue engineering method.</p><p><b>METHODS</b>BMSCs transfected by bFGF gene were cultured on PLGA matrix to assess the biocompatibility of PLGA. The cell complex was then implanted into the cartilage defect in rabbits, and its effect in cartilage defect repair was evaluated by histological observation and immunohistochemical staining.</p><p><b>RESULTS</b>BMSCs transfected by bFGF gene grew normally on PLGA matrix. After implantation, the complex showed good effect for cartilage defect repair in rabbits.</p><p><b>CONCLUSION</b>PLGA has good biocompatibility with the transfected BMSCs, and the cell complex can be used for repairing rabbit cartilage defect and may potentially serve as a substitute of cartilage autograft.</p>

Role of hepatitis C virus superinfection in hepatic pathologic changes of patients with chronic hepatitis B: a retrospective short-term and long-term comparative study / 中华实验和临床病毒学杂志

<p><b>OBJECTIVE</b>To observe the effect of hepatitis C virus (HCV) superinfection on the short-term and long-term hepatic pathological changes in patients with chronic hepatitis B (CHB).</p><p><b>METHODS</b>HCV-RNA of twice corresponding period serum samples was detected via reverse transcription polymerase chain reaction assay from 230 patients with CHB for whom liver biopsy was performed at an interval of 0.5-15 years, respectively. The hepatic pathological changes of the patients with CHB who were serum HCV-RNA positive at the beginning of observation and persistently positive between the starting and ending of observation were respectively compared with those of serum HCV-RNA negative and persistently negative patients.</p><p><b>RESULTS</b>41 patients (17.83%) were positive for serum HCV-RNA at the beginning of observation. There were significant differences in the severity of hepatic inflammatory activity grade and fibrosis stage between serum HCV-RNA positive and negative patients with CHB (P < 0.05). Twenty-nine patients were persistently positive for serum HCV-RNA in the beginning and end of observation. Compared with persistently negative patients who were 116 patients selected from the above-mentioned 230 patients and they were comparable with HCV-RNA persistently positive patients in mean follow-up time, age and sex, the long-term progression of hepatic inflammatory activity grade and fibrosis stage in persistently positive patients were more speedy (P < 0.01).</p><p><b>CONCLUSION</b>HCV superinfection worsens the hepatic pathological changes of patients with CHB and speeds up its progression.</p>