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Objective To examine whether lipoxin A4(LXA4) has an antagonistic effect on interleukin (IL)-1?-induced synthesis of IL-6 in glomerular mesangial cells, and to explore its mechanism. Methods Cultured glomerular mesangial cells (GMCs) of rat were treated with IL-1?, with or without preincubation with LXA4. Protein secretion of IL-6 in supernatants was examined analyzed by enzyme-linked immunosorbent assay (ELISA). Expression of IL-6 mRNA was determined by RT-PCR. The expression of Src homology 2 (SH2) containing protein-tyrosine phosphatase 2 (SHP-2) was assessed by immunoblotting. Activities of DNA-binding of nuclear factor-kappa B (NF-?B) were measured by electrophoretic mobility shift assay (EMSA). Results The secretion of protein and expression of mRNA of IL-6 in GMCs stimulated by IL-1? were inhibited by LXA4 in a dose-dependent manner. LXA4 reduced the phosphorylation of SHP-2 and activities of NF-?B. Pretreatmnet of GMCs with NF-?B inhibitor pyrrolidine dithio-carbamate (PDTC) blocked both the secretion of IL-6 protein and activation of NF-?B induced by IL-13- Conclusion LXA4 antagonists IL-1?-induced synthesis of IL-6 in GMCs through the pathway of SHP-2/NF-?B signal transduction.
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Objective To examine whether lipoxin A4(LXA4) induces apoptosis of rat renal interstitial fibroblasts and explore the mechanism concerned.Methods Rat renal interstitial fibroblasts (NRK 49F cells)were incubated in RPMI 1640 medium supplemented with 5%fetal calf serum and exposed to LXA4 at the concentration of 10 nmol/L, 100 nmol/L or 1 ?mol/L for 24 hours. Prior to experiment,some NRK 49F cells were transfected with Smac antisense oligodeoxynucleotide. Apoptosis of NRK 49F cells was recognized by double staining using fluorescent dye acridine orange and ethidium bromide,and observed under laser scanning confocal microscopy and counted by flow cytometry following propidium iodide and annexin staining. Activity of caspase 3 was measured by colorimetric assay. The expression of Smac was determined by Western blotting analysis.Results LXA4 at the concentration of 100 nmol/L or 1 ?mol/L induced apoptosis of 9 83%or 33 82%of NRK 49F cells respectively, and reduced the cells of S and G2～M phase and increased the cells of G0～G1 phase in a dose dependent manner. Treatment of NRK 49F cells with LXA4 up regulated the expression of Smac protein and increased the activity of caspase 3. The transfection with Smac antisense oligodeoxynucleotide inhibited the LXA4 induced apoptosis and expression of Smac in NRK 49F cells. Conclusion LXA4 at high concentration can induce apoptosis of rat renal interstitial fibroblasts via the up regulation of Smac expression.
RESUMO
In order to understand the effect of oxidant and antioxidant on proteinuriaformation of rats with passive Heymann nephritis (PHN), vitamin E (VitE), malondialde-hyde (MDA), xanthine oxidase (XOD) in serum and urine, and 24 hours protein excretionin urine were measured. The results showed that in both rats of heterologous phase (day7) and autologous phase (day 14), MDA in serum and urine, VitE and, 24 h pro-tein excretion in urine were all markedly increased, while VitE in serum was significantlydecreased, however the XOD level in serum and urine were not much altered. Correlationanalysis revealed that there were positive correlation between the amount of urinary pro-tein and that of MDA in serum and urine, and also between that of urinary protein andVitE in urine. A negative correlation existed between the amount of urinaryprotein andVitE level in serum. These results suggested that in rats with PHN there be an hyper-lipidperoxchtion with an pypo-anti-oxidation.