BACKGROUND:When the intervertebral disc is under stress, the hydraulic pressure generated inside the nucleus pulposus makes the annulus fibrosus extend outward and expand, and the annulus colagen fibers are stretched so that the extracelular matrix of annulus fibrosus cels is also under the pressure. In the intervertebral disc, aggrecan is the main component of proteoglycans, matrix metaloproteinase-2 is a major enzyme for extracelular matrix degradation, and tissue inhibitor of metaloproteinase is a multifunctional specific inhibition factor for matrix metaloproteinase activity. There is a mutual regulation between the latter two to keep the homeostasis between them.
OBJECTIVE: To investigate the mechanism of cyclic tensile strain in the metabolism of intervertebral disc annulus matrix.
METHODS:Rat anulus fibrosus cels were subjected to 2% or 10% cyclic tensile strain at 1.0 Hz for 2 and 12 hours using Flexcel4000 tension system. Then cels were colected and cultured in conditioned medium for gene and protein detection. Real-time quantitative PCR was used to detect mRNA expression of aggrecan, matrix metaloproteinases-2 and tissue inhibitor of metaloproteinase-2. Gelatin zymography was used to detect matrix metaloproteinases-2 activity.
RESULTS AND CONCLUSION:The use of 2% cyclic tensile strain had no obvious effect on the stress fiber of actin cytoskeleton, whereas actin cytoskeleton was depolymerized in response to 10% cyclic tensile strain. The 2% cyclic tensile strain raised the expression of Aggrecan at 12 hours; whereas raised the matrix metaloproteinases-2 and tissue inhibitor of metaloproteinase-2 at 2 hours, both of which were in homeostasis; matrix metaloproteinases-2 activity had no significant changes. 10% cyclic tensile strain had no effect on the mRNA expression of Aggrecan. No matter stretching 2 or 12 hours, the matrix metaloproteinases-2 was up-regulated, and the tissue inhibitor of metaloproteinase-2 was down-regulated, both of which were not in balance. Moreover, the matrix metaloproteinases-2 activity was not significantly changed. These findings indicate that the mRNA expressions of Aggrecan, matrix metaloproteinases-2 and tissue inhibitor of metaloproteinase-2 alter in response to cyclic tensile strain in rat anulus fibrosus cels, and the tensile strain induces different mechano-responses in the actin cytoskeleton.

AIM: To investigate the effect of c-Myc inhibitor 10058-F4 on human chronic myeloid leukemia ( CML) K562 cells and imatinib-resistant K562/G cells.METHODS: The protein expression of c-Myc was detected by Western blotting .Cell proliferation was evaluated by MTT assay and colony formation assay .PI staining was used to deter-mine the cell cycle distribution .Annexin V-PI staining was applied for apoptosis detection .RESULTS:Imatinib-resistant K562/G cells displayed lower sensitivity to imatinib than K 562 cells with high expression of c-Myc.Treatment with specific c-Myc inhibitor 10058-F4 inhibited the cell proliferation in a dose-and time-dependent manner , and K562/G displayed more sensitivity to 10058-F4 than K562 cells.10058-F4 also induced cell cycle arrest in G 0/G1 phase and induced apoptot-ic cell death in the 2 cells.Importantly, 10058-F4 suppressed the colony formation ability in K 562 and K562/G cells. CONCLUSION:c-Myc is a novel target to overcome imatinib-induced drug resistance , and c-Myc inhibitor provides a new approach in CML therapy .

Aim To study the modulation of KCNQ2/3 potassium cha nn els by extracellular pH.Methods In vitro transcription was used to synthesize cRNA of KCNQ2/3 potassium channels.The cRNA was injected into Xenopus oocytes to express the KCNQ2/3 channel.The modulation of KCNQ2/3 potass ium channels by extracellular pH was studied by two electrodes voltage clamp tec hniques.Results KCNQ2/3 currents were inhibited and current-vo ltage relationship of activation were shifted to the right with decreased extrac ellular pH. pH modulation of KCNQ2/3 currents was voltage dependent,with a more pronounced effect at more negative potentials above the activation threshold (-60 mV). Extracelluar pH also decreased activation and deactivation kinetics of KCNQ2/3 currents.Conclusion KCNQ2/3 channels, known to contr ibute to neuronal excitability, were modulated by extracelluar pH. The profound effects of the extracelluar pH exerted on KCNQ2/3 channel may play an important role during physiology neuronal activity and pathological events such a s epileptic seizures, cerebral ischemia and shock etc.

Objective:To construct the eukaryotic expression plasmid carrying hTERT-P2A-EGFP, and to explore its expression and transfection efficiency in the HEK293FT cells.Methods:The recombinant plasmid was constructed by using pBABE-puro-hTERT and pRRLSIN-cPPT-MSCV-EGFP plasmids.The hTERT,P2A,and EGFP genes were obtained using pBABE-puro-hTERT as template by PCR.And the correct hTERT was inserted into pRRLSIN-cPPT-MSCV-EGFP vector.Then the recombinant plasmid containing hTERT-P2A-EGFP gene was obtained and identified.The HEK293FT cells were transfected by the recombinant plasmid, and the expression of green fluorescence protein(GFP) was observed by fluorescence microscope.Results:The PCR results showed that the fragments of hTERT, P2A, and EGFP were 3 400, 110 and 720 bp.And the length of gene fragment(hTERT-P2A-EGFP)was 4 300 bp by enzyme digestion.The results of sequencing showed that the 1 547 site of the target gene was mutated.Using site-directed mutagenesis, the 1 547 site was successfully mutated.And the target gene sequence was completely identical with the sequence published in GenBank.The recombinant plasmid was transfected into the HEK293FT cells, and GFP was observed in the cells.The results of flow cytometry showed that the transfection efficiency of recombinant plasmid was 44.8%.Conclusion:The recombinant plasmid carrying hTERT-P2A-EGFP gene is successfully constructed, and it can be used for cell transfection.

To investigate the effect of MMP-26 on human glioma angiogenesis and the possible mechanism.Methods The MMP-26 plasmid and empty plasmid pcDNA3.1 were stably transfected into U251 cells to establish a nude mice xenograft model,and then an in vitro human tumor tissue-based three-dimensional angiagenic model.Tissue disks were visually assessed over time to determine the percentage of wells that developed an angiogenic response(I％) and the density and length of neovessel growth were graded at intervals using a semiquantitative visual growth-rating scheme (angiogenic index,AI,0-16scale) in groups of MMP-26 transfected U251 cells (U251-MMP-26),pcDNA3.1 vector-transfected U251 cells (U251-pcDNA3.1) and non-transfected U251 cells (U251).RT-PCR and immunohistochemistry were used to detect the expression of mRNA and protein of MMP-26 and VEGF in groups of U251-MMP-26,U251-pcDNA3.1 and U251.Immunohistochemical localization of CD31 was determined in the endothelial tubes invading the fibrin-thrombin clot matrix.Results Immunohistochemical endothelial cell markers CD31 was positive in the vascular tubes invading the fibrin-thrombin clot matrix,confirming their endothelial origin.The angiogenesis results showed that difference of length of micro capillaries,density of branches,and the area occupied between U251-MMP-26 groups and control groups were significant.The percentage of tumor implants that developed invasion (I％) and the angiogenic index AI in U251-MMP-26 group on day 14 were higher than those of U251-pcDNA3.1 group and U251 group (P ＜ 0.05).The trends of I％ and AI in 14 days were significant compared with those in control groups.The expression of mRNA and protein of MMP-26and VEGF in U251-MMP-26 group was significantly higher in U251-MMP-26 group than those in U251-pcDNA3.1 group and U251 group(P ＜0.01).Conclusion The effect of MMP-26 on promoting glioma angiogenesis may be related to the increased expression of VEGF,which can be used as targets for anti-tumor therapy.

Objective To investigate the role of renin angiotensin system (RAS) in pathogenesis of nonalcoholic fatty liver disease (NAFLD).Methods Twenty-four Wistar rats were evenly divided into control group and model group.The rats of control group were fed with normal diet,and model group were with high-fat diet.Rats were killed at the eighth week and serum liver function,blood lipid,glucose and insulin were tested.The liver tissues were stained with HE and Picro acid-Sirius red for pathological observation.The liver tissue concentration of angiotensin Ⅱ was determined by ELISA method and the expression of TGF-β1 in liver tissue was examined by immunohistochemistry.Results After eight weeks high fat feeding,weight,liver index,liver function,blood lipids and serum insulin of model group were significantly higher than those of control group (weight:(463.50±22.72) g vs.(404.29±10.32) g; liver index:(3.75±0.21) g vs.(2.66±0.15) g; ALT:(79.8±8.6) U/L vs.(58.8±11.6) U/L; AST:(200.01±51.72) U/L vs.(150.30±37.27) U/L; total cholesterol:(3.67±0.48) mmol/L vs.(1.50±0.23) mmol/L; triglycerides:(2.06±0.40) mmol/L vs.(0.71±0.34) mmol/L; insulin:(17.37±2.89) pmol/L vs.(11.08±2.12) pmol/L),and all the differences were statistically significant (P＜0.01).The histopathological results of model group indicated liver steatosis,inflammatory reaction in part of lobule and portal area and significant fibrosis in part of liver tissue.The liver tissue angiotonin Ⅱ concentration of model group [(32.80 ± 2.81)pg/ml] was higher than that of control group [(22.83 ± 1.75) pg/ml,t =9.559,P＜0.01].The immunohistochemistry results showed that the expression of TGF-β1 of model group was obviously higher than that of control group (Z=-2.540,P =0.011 ).Spearman correlation analysis revealed that the increasing degree of angiotensin Ⅱ concentration was positively correlated with liver steatosis scores (r=0.644,P=0.002) and the expression of TGF-β1 (r=0.470,P=0.037).Conclusion The concentration of angiotensin Ⅱ and TGF-β1 increased in the livers of model rats,which indicated that RAS may participate in the pathogenesis and progress of NAFLD.

Aim To investigate the effect of Salvianol-ic acid A (Sal A)on mice with isoproterenol (ISO)-induced myocardial infraction and its possible mecha-nisms.Methods The mice were subcutaneously in-jected with ISO (8 mg·kg-1 )to induce myocardial in-farction.The myocardial protective effect of Salvianolic acid A was evaluated from mortality rate,electrocardio-gram (ECG),heart function,myocardial infarction in-dex,serum myocardial enzymes and its action mecha-nisms were explored from inflammation,anti-oxidation and cells apoptosis.Results Salvianolic acid A dose-dependently enhanced the heart function of myocardial infarction mice,reduced the heart index,inhibited the myocardial enzyme leakage,showed obvious myocardi-al protection effects.ELISA results showed that Salvi-
anolic acid A could reduce the expression of myocardial inflammatory cytokines such as IL-6(interleukin-6,IL-6),TNF-α(tumornecrosis factor-α,TNF-α).West-ern-blotting confirmed that Salvianolic acid A could in-crease the expression of anti-apoptotic proteins Bcl-2, reduce the expression of apoptosis protein Bax,and raise the phosphorylation level of PI3K and Akt.Con-clusion Salvianolic acid A displays a significant pro-tective effect against isoproterenol-induced myocardial infarction and its mechanism may be related to the in-crease of PI3K/Akt signal pathway and the inhibition of cell apoptosis and inflammatory reaction.

This study is to investigate the effect of total flavonoids of Uygur medicine bugloss (BTF) on rats with myocardial ischemia/reperfusion injury, and to explore the mechanisms by which it acts. Left anterior descending (LAD) coronary artery in rats was occluded for 30 min followed by 4 h reperfusion. Meanwhile, BTF dissolved in saline was administered intraperitoneally at dosage of 10, 30 and 50 mg x kg(-1). Electrocardiograph, infarction index, serum myocardial enzymes and heart function were determined to evaluate the effect of BTF. Some other observations were carried out to explore whether inhibiting inflammation and apoptosis is involved in the mechanisms underlying BTF. Our results showed that in ischemia/reperfusion injured rats BTF could dose-dependently reduce myocardial infarction index and myocardial enzyme leakage, and enhance heart function, indicating that it possesses significant cardio protection. ELISA analysis showed that BTF could decrease the content of myocardial inflammatory cytokines such as IL-1beta, IL-6 and TNF-alpha. Western-blotting confirmed that BTF could increase the expression of anti-apoptotic protein Bcl-2 and reduce the expression of proapoptosis protein Bax. Further more, the phosphorylation level of PI3K and Akt was upregulated by BTF treatment. BTF can protect rat against myocardial ischemia/reperfusion injury. Anti-inflammation and inhibition of apoptosis through upregulating PI3K/Akt signal pathway may contribute to the protective effect of BTF.

Objective To observe the therapeutic effect of catgut-embedding (CE) therapy based on respiration-induced reinforcing and reducing and electro-acupuncture (EA) therapy in treating simple obesity with spleen deficiency and dampness retention. Methods Sixty simlpe obesity patients with spleen deficiency and dampness retention were randomized into CE group and EA group, 30 cases in each group. The acupoints selected for the two groups were the same, and the points were Zhongwan, Shuifen, Qihai, Guanyuan, Tianshu, Liangmen, Daheng, Fujie, Quchi, Xuehai, Yinlingquan, Fenglong, and Ashi. CE group was given CE therapy with the needling for CE therapy referred to the respiration-induced reinforcing and reducing method, and EA group was given EA therapy for 2 continuous treatment courses, 4 weeks constituting one course. Body mass and body mass index (BMI) of the two groups before and after treatment were observed, and the clinical efficacy was also evaluated after treatment. Results (1) After treatment for 2 courses, body mass and BMI of the two groups were obviously decreased(P<0.05 compared with those before treatment), but the differences between the two groups were insignificant (P > 0.05). (2) The total effective rate of CE group was 90.0% and that of EA group was 86.7%, and the difference between the two groups was insignificant (P > 0.05). Conclusion The therapeutic effect of CE therapy based on respiration-induced reinforcing and reducing in treating simple obesity with spleen deficiency and dampness retention is similar to that of EA therapy, and the patients can choose anyone of them for loosing body weight according to the preference.

Dioscin chemical compositions are the main effective components in clinical commonly used Chinese medicines such as Diaoxinxuekang capsules and Xinnaoshutong capsules etc , which show distinct curative effect on cardiovascular and cerebrovascular diseases.Meanwhile, they are the important raw materials for the synthesis of steroid hormone drugs .The studies on the extraction technology exhibit important significance in the exploration of pharmacological activities of the components , which also are the external requirements for the growing demand of steroid hormone drugs market .In this paper , the relatively mature extraction methods re-searched in recent years were summarized ,and the advantages and disadvantages of the different processes were discussed in order to provide reference for the further studies and application .